English Instruction Book No. 10 Copyright © 1956 Kelvin Diesels PLC

The Running and Repairing of


 1. WHILE it is not necessary to read this instruction book right through, it is essential before starting a new engine to read those paragraphs marked thus, *, and to see that the crankcase contains oil. No subsequent adjustment or repair to the engine should be carried out without reference to the book. Any advice we can give is at your service whether you are the original purchaser of the engine or not. When writing, do not omit to quote the number of the engine stamped on the crankcase.

    *2. TOOL BOXES.--A box of tools accompanies each engine. It is closed with a lead seal, and, if delivered with the seal broken, its contents should be checked with the list to be found in the engine catalogue. Provide a dry place for the tool box and hang the finger pin which operates seacock on a convenient nail.

    3. REPLACEMENTS.--All the parts of current models are in stock, also the parts of our oldest models for which there is a regular demand. Please describe the parts which you require in the terms of the price list which is contained in the tool box. We carry in stock boxes containing a selection of spares suitable for customers in remote districts; contents and price as per price list. To England, Scotland, Northern Ireland, Isle of Man and the Channel Islands, goods not exceeding fifteen pounds (in each package) may be sent by post C.O.D. (cash on delivery). Buyers abroad may have goods sent C.O.D. if they satisfy themselves that the system is available, see par. 69.

    Authorised Kelvin Agents are restricted in the matter of Kelvin spares to parts obtained from us. Many imitation Kelvin parts are, however, on sale, and you are advised to satisfy yourself that the parts offered you were obtained from The Bergius Company. We shall disclaim responsibility for the performance of an engine as soon as we know that it contains parts which are not genuine Kelvin spares.

    *4. PARAFFIN.--We are frequently asked which is the best brand of oil for use in a paraffin engine. The question is difficult to answer because merchants sometimes sell different oils under the same brand, and the same oil under different brands. The correct fuel is usually described as vaporising oil but users in the United Kingdom are advised to write to the undermentioned, asking which of their brands is most suitable for a "Kelvin" Engine, and the name of their nearest authorised agent. Users abroad are advised to try all available brands and select the one which works with least tendency to knock.  


Shell Mex. and B.P. Ltd. Shell Mex House,Victoria Embankment. London, W.C.2.
British Petroleum Co., Ltd.. Britannic House, Finnsbury Circus, London, E.C.2.
Scottish Oils Ltd., 53 Bothwell Street, Glasgow, C.2.
Esso Petroleum Co., Ltd., 83 Albert Embankment. London, S.E.11.

    *5. LUBRICATING OIL.--Lubrication is the most important care of an oil engine. Use good oil such as is sold for motor cars, and see that it is delivered to you with the maker's seal intact.

    *6. LUBRICATION.--The pistons are lubricated by splash from the crankcase. The arrangement of webs within the crankcase is such as to ensure sufficient lubrication to the forward piston, even if the rake of shaft amounts to 1 inch in 9 inches. The crankcase should contain only sufficient oil to reach the split pin of each crankpin bolt when in its lowest position. To maintain sufficient oil in the crankcase, the oil dripper should be set to drip when the engine is started and shut off when the engine is stopped. The number of drips per minute is stamped on the milled screw.

    7. CRANKCASE should be cleaned out every 100 hours of running. If this is neglected grit and burnt oil accumulate and destroy the bearings. Any evidence of water such as rust on the bright parts should be investigated at once.

    *8. ENGINE INCLINED.--An engine stopped at any time should contain in each division of the crankcase sufficient oil to reach the point of the crankpin bolt. The sloping oil ducts visible within the crankcase keep the oil constantly circulating from the rear to the front, ensuring that the forward piston gets its share, even although the engine may be inclined to the extent of 1 inch in 9. As the engine must not be worked at a greater inclination than 1 in 9, it is advisable to measure the inclination when the boat is at full speed. This may be done either with a spirit level laid on some part of the engine, or with a plumb line held in front of the flywheel.

    *9. OIL DAILY.--(a) All oil cups about the engine (These should contain cotton to prevent grit entering the bearing); (b) the governor at 3 holes; the throttle valve; (c) the clutch within the gear box at the hole marked "Oil." (Neglect of this causes it to stick fast. Put no oil into the reverse gear case); (d) the bearings of the shafting (The oil cup should contain cotton); (e) the staring handle where it fits so that it may come out with certainty when the engine starts; (f) the rollers of the reverse lever.

    *10. STARTING A NEW ENGINE.--Before starting a new engine fill the cylinder waterjacket by the small oval flange and the  circulating pump by its cover. Before doing so close the seacock at the hull to prevent the water running through. Open the seacock when the engine starts.

    See that the crankcase contains sufficient lubricating oil to reach the split pin of each crankpin bolt when in its lowest position. Oil the engine according to paragraph 9.


The starting of engines should be done strictly as follows:-

11. PETROL ENGINES.    (3 1/2, 7 and 14 horse power.)

12. PARAFFIN ENGINES STARTED BY PETROL.    (3, 6 and 12 horse power.) 13. PETROL ENGINES.    (8, 15, 30 and 60 horse power.) 14. PARAFFIN ENGINES STARTED BY PETROL.   (7, 13, 26 and 50 horse power.)     *15. TO STOP ENGINE.--Retard ignition (lever down), close throttle, place the stopping wire on the brass terminal.

    *16. WARMING UP.--Paraffin engines started by petrol heat up more quickly if run with the ignition retarded (magneto lever down).

    17. SLOW RUNNING.--It should be possible to slow down an engine to one-half of its full speed by merely closing the throttle and retarding the ignition (magneto lever down) but a four-cylinder engine will not continue to run slow-on paraffin unless two of the cylinders are cut off by closing the fuel supply. The forward pair should be cut off A larger jet may admit of slower running, but accumulates soot in the cylinders (41).

    18. CARE OF ENGINE.--Kelvin engines are designed to be easily kept clean--all parts are rounded--no sharp edges. Use cotton waste obtainable from chandlers--old cloth is not suitable--keep your waste dry. Wipe your tools each time you use them.

    ENGINE NOT  FIRING PRIMING.--Causes: (a) overprimed--turn the engine with priming valves open; (b) poor petrol--heat sparking plugs; (c) lack of spark--test plugs (28); (d) magneto contact breaker stuck (32); (e) magneto wrongly set (37); (f) valves stuck up--examine them while turning the engine.

    20. ENGINE STARTS, BUT STOPS.--See that the fuel supply is clear. A full stream Should run below the float chamber when the milled nut there is slackened. If the tanks have been allowed to run empty, the pipe may be "air-locked "--blow into the tank. Water may have gained access to the tank. Try the sediment cock below the tank. See that the spray jet is clear. The air valve stem may have worked loose.

    *21. ENGINE RUNNING HOT.--If the cylinder water jackets are more than hand hot, ease the small oval flange on top of the cylinder to release any air which may have collected there. If the water pipe from the cylinder to the silencer is more than hand hot, take off the pumps to see that the pistons are working (46). If the bearing at the aft end of the engine runs hot (48).

    22. ENGINE MISFIRING.--If an engine fires irregularly, open the compression cocks one by one to ascertain which cylinder is missing (28, 29, 30, 33).

    23. ENGINE KNOCKING.--If the knock is within the crankcase, look for something loose, misplaced, or hot (56). If the knock is within the cylinder, and only when running at full speed, it may be due to (a) the quality of the fuel--try another brand (4); (b) excessive soot within the cylinders; (c) too heavy a propeller (60).

    Generally speaking, a richer mixture reduces the tendency to knock in a paraffin engine. Try a reduction in the number of washers at the air valve or a larger spray jet (40). A weak mixture, due to partial stoppage of the spray jet or filter, causes knocking in a paraffin engine.

    24. ENGINE SEIZED.--If an engine suddenly stops, and cannot be turned, look for heat in the bearings of the crank shaft and reversing gear. If there is no heat in the bearings, the pistons are probably stuck fast by bad lubricating oil (5), or they are "seized" for want of oil (6). Inject paraffin into the cylinders, and apply pressure to the starting handle while giving the pistons a sharp knock with an iron bar applied through the cylinder top. Try turning in both directions by the flywheel.

    *25. ENGINE FLOODED.--The exhaust must discharge slightly above sea level. The silencer must be above the point of discharge. There is no objection to a downward dip in the pipe, but no part of the pipe must be above the silencer. The best arrangement is to give the pipe a gradual fall throughout its length from silencer to point of discharge. If these conditions have not been fulfilled report the arrangement and the engine number.

    26. ENGINE BECOMING SOOTED UP.--This may be due to bad lubricating oil (5) or to excessive lubrication (6) or to the carburettor having become out of adjustment (40). If the carburettor is suspected, report to us the number of the spray jet, the number of washers at the air valve, and the number of the engine. A whiteness on the valve head is due to salt water (25).

    27. ENGINE LOOSING SPEED.--If the loss has been gradual it may be due to an accumulation of soot and salt in the silencer--clean it out--or to the fouling of the vessel below water. A growth not visible to the eye is sufficient to affect the speed. If the bottom is slippery to the hand the boat requires cleaning. It pays to use anti-fouling paint, as the best qualities (all brown in colour) resist growth in a temperate climate for four months--growth begins on ordinary paint in four weeks. There are various makes, but a good brand is obtainable from the International Paint & Composition Company, Ltd., Grosvenor Gardens House, London, S.W.1.
    28. SPARKING PLUG TEST.--Take out plug, lay it on engine so that its body alone makes contact, turn engine by hand. If no spark results (29).

    29. SPARKING PLUG ADJUSTMENT.--The spark gap becomes wider with use, and the points should be bent to maintain the gap at .5 m/m or .020 inch (gauge attached to magneto spanner). The size of the spark is in proportion to the width of the gap. A spark too small may fail to start the engine, but a gap too wide may fail to produce a spark. A plug which sparks in the open air may not do so when exposed to the pressure within the cylinder--such a plug may start the engine if the priming valves are kept open. If the magneto is suspected of being weak keep the gap of the sparking plugs rather close.

    30. SPARKING PLUG MISSING.--If due to soot bridging the gap, it may be cured without stopping the engine by detaching the terminal from the plug and holding it (by the cable) at some distance from the plug. The long spark thus produced intensifies the electric current. If missing is due to soot within the body of the plug, take it to pieces. If due to causes described in par.3l throw it away.

    31. SPARKING PLUG, CARE OF.--Porcelain plugs must be handled with care. A spanner carelessly applied may produce in the porcelain an invisible crack which in time holds moisture and causes the plug to short. The thread of the sparking plug should be oiled.

    32. MAGNETO CONTACT BREAKER.--The moving arm is liable to become stuck in damp climates owing to the swelling of its fibre bush. Remove the arm, polish and oil the pin; scrape out the fibre bush with the square tail of a small file or other suitable instrument. As this operation takes time, it is advisable to carry a spare contact breaker. The fibre pad on the end of the arm should be oiled, but no oil must reach the platinum contacts.,

    33. MAGNETO CONTACT BREAKER GAP.--The contact points are platinum tipped, and gradually wear further apart, with the result that the gap increases. A gauge is attached to the magneto spanner; try it in the gap, and, if necessary adjust the screw.

    34. MAGNETO DISTRIBUTOR.--Some distributors have carbon brushes which wear. The dust produced must be removed from time to time. When the brushes wear down they should be renewed (36); the stretching of the spring serves temporarily.

    *35. MAGNETO, CARE OF.--Allow no oil or petrol to drip on to the magneto as that causes rapid wear of the platinum contacts. The magneto requires only three drops, of oil once a month.

    36. MAGNETO REPLACEMENTS.--Owing to the great variety of magnetos which we have been obliged to supply, we cannot keep stock of all magneto replacements, and buyers are advised to communicate direct with the magneto maker, taking care to quote the number of the magneto if it bears one. A magneto sent to the maker should be labelled with the owner's name, and its despatch advised to the maker.    


BOSCH MAGNETOS. Bosch Limited, Larden Road, Acton, London, W.3.
SIMMS MAGNETOS. Simms Motor Units Ltd., Oak Lane, East Fincley, London, N.2.
LUCAS MAGNETOS. Joseph Lucas, Ltd., Great King Street, Birmingham, 9.
B.T.H. MAGNETOS British Thomson Houston Co., Ltd., Alma Street,  Coventry.
    37. SETTING THE MAGNETO.--The magneto produces an intermittent current. To ensure that the flow of current coincides with the firing points, the magneto must be "set" with some relation to the crank. Should a magneto chain be removed or renewed, the magneto must be re-set. Proceed as follows: Turn the engine until figure 1 on the aft side of the gear wheel is uppermost.     It is now necessary to connect each wire to its proper sparking plug. The magneto feeds only one wire at a time. Ascertain by examination of the distributor which wire is being fed, and connect it to the sparking plug of the cylinder which is under compression. The figure uppermost on the gear wheel indicates the cylinder under compression.
    38. FIRING ROTATION.--The cylinders are marked 1 2, 3, 4, beginning forward. The firing rotation of a four cylinder engine is 134213421342. The firing rotation of a two cylinder engine is 120012001200.

    39. IMPULSE STARTER.--This device is controlled by the milled nut at the fore end of the engine on the port side. In operation it accelerates the magneto at the moment of firing, thereby producing a more robust spark. Slacken the milled nut for starting, but tighten it immediately the engine starts.

    40. CARBURETTOR--The carburettor is composed of several parts, with which you should become familiar. Take it to pieces. The fuel pipe terminates in the "needle valve," which is controlled by the "float." From the float chamber the oil flows to the spray jet, where it meets the air. The narrow passage surrounding the spray jet is called the "choke." The "mixture," after passing the "choke," is joined by air admitted from the air valve. This mixture passes through the throttle valve, and the vaporizer to the cylinder. If there is a drip from the float chamber, examine the needle valve, and, if necessary, lightly grind it in its seat. Shake the float to see that it is empty. If not, get a replacement. If you wish to try a change of jet order one larger and one smaller than the one fitted. A change of jet may entail a change in the adjustment of the air valve order some additional air valve washers.

    The number stamped below the air valve represents the number of washers originally fitted, and the spare jet is a duplicate of the original one.

    41. SPRAY JETS are all tested, and the number represents the actual flow through the jet. Never tamper with the orifice. If you wish to experiment get additional jets from us.

    42. GOVERNOR.--The rods connecting the vertical governor leaver with the throttle valve should be so adjusted that the throttle valve markings coincide when the governor balls are fully extended . The length of the chain should be such that the markings on the throttle valve coincide when the throttle lever is full down. The engine will be found very convenient for manoeuvring with one spring removed from the governor, as when working in a canal.

    43. VALVES LEAKING.--The power of an engine depends largely upon the gas tightness of its valves. To test the tightness; turn the engine slowly by hand and listen for leakage. The valve and the seat should both show a continuous bearing all round. If part of the circle is black, apply some of the grinding, paste, which will be found in the tool box, and turn the valve to and fro by means of a screw driver.

    44. VALVE ADJUSTMENT.--The lower end of the valve stem should be clear of the plunger by the thickness of a visiting card when the valve is down. To reduce the clearance, remove the cap from the plunger and insert one or more of the small brass discs, which will be found in the tool box. Excessive clearance produces noise; insufficient clearance prevents the valve reaching its seat and, causes it to become burned on the face.

    45. PISTON RINGS.--If good lubricating oil is used the rings never require cleaning. If a ring becomes stuck in its groove ease it with paraffin, if possible without removing it--a ring prized out of the piston is sprung and no longer gas tight. Piston rings should be handled with care. Their condition indicates the quality of the lubricating oil in use.

    *46, PUMPS.--If no water is discharged along with the exhaust, stop the engine at once, and take off the pump to free the pistons. These are of leather, with a serrated internal spring, the points of which, should be bent out to keep the leather in contact with the pump barrel. If water is discharged from the underside of the pump, the leather is probably worn out; order a replacement. The holes on the underside of the pump are to drain away any leakage past the pump piston, and these holes should on no account be closed up, else the water will gain access to the crankcase. If the leather becomes hard grind or renew the valves.

    *47 PUMP STRAINER.--Keeps clear when the boat is underway but becomes readily choked if the engine is kept running while the boat is at rest in shallow water as when lying beside a jetty, especially after the reverse gear has churned the water. It is important to know immediately if the strainer has become choked--one method is to feel frequently the waterpipe from cylinder to silencer; a better method is to keep the copper exhaust pipe painted with oil paint. Immediately the strainer becomes choked the water fails, the exhaust pipe becomes hot and creates a smell which warns you to stop the engine.

    48. BUSH AT REAR OF REVERSE GEAR RUNS HOT.--Cause (a) lack of oil--examine oil cup; (b) shaft out of line--remove shaft coupling and check alignment of shafts with steel rule or blade of carpenter's square (52). If an engine is close to the sterntube the shaft lacks sufficient elasticity to allow for the shrinkage of the foundation and the alignment of such installations should be verified annually.

    49. CLUTCH SLIPPING.--Causes: (a) propeller blade bent; (b) shafts out of line (52); (c) propeller of excessive pitch. Report engine number, dimensions of boat, speed of engine with throttle held full open and speed of boat.

    50. CLUTCH STICKING FAST.--Causes: (a) lack of oil (9); (b) cones bearing unevenly--file inner cone to obtain bearing all over. To release a clutch stuck fast strike shaft coupling with a heavy hammer while applying pressure to the lever.

    51. CLUTCH WORN OUT.--Causes: (a) manipulating the clutch without first slowing the engine; (b) running with the clutch slipping (49).

    52. SHAFT COUPLINGS must be tight. If once they slip both coupling and shaft become torn and ruined. All parts of the shaft coupling should be painted before being assembled. If shaft runs out of truth it is probably due to unequal tightening of the bolts. Hold a pencil to the running shaft and tighten the bolts on the side marked by the pencil.

    53. GEAR WHEELS.--If the flywheel is removed, see that it is replaced so that the marked teeth mesh with one another. Should a new (unmarked) gear wheel be fitted, mesh the teeth of it so that the exhaust valve closes and the inlet valve opens with the piston at the top (the inlet valves are those in the centre). When so meshed, mark the teeth of the new wheel with a file. A small piece of chalk dropped in the teeth serves to mark them until the file can be applied.

    54. VAPORIZERS.--If the vaporizer gets cracked, water may be the cause (25). In a four-cylinder engine a cracked vaporizer may be due to the two cylinders not being in line with one another. Take off the vaporizer and apply a straight edge to the cylinders.

    55. FLYWHEEL.--To remove flywheel take off nut, strike the end of shaft with a hammer weighing at least 4 lbs. while applying a piece of wood behind wheel as a lever. Protect end of shaft with a piece of copper brass while striking it.

    56. BEARINGS.--~It is advisable to obtain the replacements which may be necessary before dismantling the bearings, otherwise the engine must stand awaiting them or be fitted with bearings locally made of doubtful material and workmanship (3). As the end bearings are not split, the tightening of them involves new bushes, and if the shaft is worn undersize, it must be machine ground. We stock bushes undersize which may be machined out locally to fit the reduced shaft; The middle bearing of a four-cylinder engine should be examined periodically to see that the four screws are tight but avoid over-tightening them. The big ends are adjusted by removal of liners. When sent out they have the same number of liners on each side, but it is permissible to remove a liner from one side only which gives the fineness of adjustment necessary.

    *57. THE STERNTUBE must have the stuffing box outside in order to keep out sand. It is not desirable to fit two stuffing boxes because (a) that permits the neglect of the outer or more important one and (b) causes considerable friction. Outside stuffing boxes should be tightened each time the vessel is ashore for cleaning--neglect to do so may involve the cost of having the vessel laid ashore. If you have no proper packing use rope yarn and tallow--mineral grease is not so good. Avoid packing which contains india rubber or anything sticky. Insert the packing one turn at a time. Secure the screws with monel wire (some in tool box). Copper does not last.

    58. PROPELLER SHAFT VIBRATION.--Causes; (a) Lack of clearance between propeller and woodwork (62); (b) slackness of shaft in sterntube due to neglect of outer stuffing box (57); (c) propeller blade bent; (d) shaft out of truth (52).

    59. BALL BEARINGS.--The failure of ball bearings is seldom due to fair wear or to original defect, but almost always to lack of protection from damp or to defective mounting. As soon as the burnished surface of the balls shows rust the failure of the bearing is imminent. A "Thrust" bearing consists of two loose washers with a ring of balls between. When the two washers are quite alike the reassembling of them presents no difficulty, but when the one washer is larger in the bore than the other the two must not be interchanged. "Journal" bearings consist of two rings with balls between. The inner ring must be a press fit on the shaft, and the outer ring must be a sliding fit in the housing. Ball bearings having a broken ball cannot be repaired, but if all trace of the broken ball is removed the bearing may run for a considerable time.

    60. PROPELLERS should be removed with a heavy hammer--a light one harms the propeller without removing it. Secure the nuts with a turn of Monel wire through the end of the shaft. If you consider the propeller unsuitable for your boat, report to us the length, beam and draught of the boat, the speed of the engine with the throttle held fully open, and the markings on your propeller.

    61. FOLDING PROPELLER.--The blades open when the propeller begins to revolve and close when the engine is stopped or the clutch withdrawn. Before opening the blades slow the engine and bring the vessel completely to rest. If the blades are opened with the engine running fast the shock is sufficient to bend them. The bolt should be so adjusted that the blades are sufficiently free to open by their own weight. Excessive vibration indicates that one blade is open and the other closed. Do not run under this condition.

    62. PROPELLER INEFFICIENT.--Causes: (a) Lack of clearance between propeller and woodwork--increase the aperture wherever possible; (b) sternpost too clumsy--reduce it as much as possible; (c) rudder post too thick--reduce it or abolish it; (d) diameter or pitch of propeller not suitable. Report the engine number length, beam and, if possible, the speed of the boat, also the speed of the engine with the throttle held full open against the action of the governor.

    *63. ENGINE FOUNDATION.-- All Kelvin models are designed to rest on two transverse bearers (longitudinal bearers are not suitable.) The bearers must be of hardwood and should rest direct on the planking clear of ribs. In boats having steam-bent ribs the bearers must run up the bilge to the height of the flywheel centre, but in boats with grown frames the bearers may be straight on the upper surface. The bearers should be fastened from outside with Kelvin bolts and drawn hard down to the keel with a Kelvin wood stud. This should be tightened once a year as the wood shrinks.

    64. ENGINE NOT PROPERLY INSTALLED.--If you consider that the work of installation has not been properly carried out, apply to us for a set of installation sheets and quote the engine number stamped on the crankcase.

    65. TANKS.--A tank aft of the engine must have a margin of height to allow for  the sinking of the stern when the launch is under way. Petrol tanks are dangerous below deck where lamps are ever present  and should be installed where exposed to the open air. Although galvanized, all tanks should be painted before being fixed.

    66. SPEED IN RELATION TO POWER.--The resistance of a vessel to propulsion is due to two distinct causes--surface friction and wave making. Surface friction is present at all speeds. Wave making is absent at a low speed, commences suddenly and increases rapidly. It follows, therefore, that any boat is easily driven up to its wave-making speed, and beyond that only by an extravagant expenditure of power, If economy in first cost or in running expense is of importance, it is advisable to instal only sufficient power to produce the wave-making speed. It is a common fallacy that a vessel with good lines must be easily driven. At low speeds the lines count for nothing, because surface friction is the whole source of resistance. At higher speeds what counts is the relation between the displacement (weight) and the water line length. It follows that an increase of speed should be sought by decreasing the displacement or increasing the length rather than by increasing the power. These remarks will explain why heavy short high-powered craft are disappointing in speed.

    67. WINTERING.--Before laying up an engine for the winter it is important to remove any salt dried on to it, this draws damp and causes an excessive rusting action. To do so, wash down the engine with hot water. Drain all the water from the cylinders, pumps, and from any pipe bend where water can lie. Pour some lubricating oil into each cylinder, and turn the engine by hand. Coat everything not protected by paint with vaseline. As a wooden vessel exudes moisture inside for about 6 months after being hauled up, it is necessary to provide continuous ventilation if excessive rust is to be avoided.

    68. JOINTS. --Each boat should carry a stock of all joints, obtainable from us. In cases of urgency joints can be cut from certain materials ordinarily obtainable from motor dealers or plumbers. For exhaust use "asbestos millboard" coated with black lead to prevent adhesion; for water connections use "rubber insertion." Red fibre withstands oil and water, but not heat. Anything containing india rubber does not withstand Petrol, Paraffin, or Oil, for which use cloth or paper saturated in syrup or shellac.

    69. IMPROVEMENTS.--Improvments to Kelvin engines are introduced from time to time. Wherever possible they are so designed that they can be added to old models.

    Silent gear wheels can be supplied for the reversing gear of engines having the gears made of iron. (This improvement is confined to engines having 3 1/2 inch cylinders).

    If your propeller shaft bracket keeps wearing out, try our new model with stuffing box integral. This bracket is cast of tough gunmetal, so that the arms may be bent to make the palms lie fair to the vessel's planking.

    Filters were at one time embodied with the carburettor, where they were rather difficult of access. Separate filters can now be supplied to mount on the pipe line in any convenient position.

    We are frequently asked to convert the ignition of old models from low to hi tension To do so is costly and unsatisfactory. It is preferable to thoroughly overhaul the low tension system and renew all its moving parts. The cost of this is trifling compared with the cost of conversion.

    We are sometimes asked to convert petrol engines so as to consume paraffin. To do so properly involves the fitting of shorter connecting rods, a vaporizer, an alteration to the carburettor, the addition, of a petrol starting tank and piping, also a smaller propeller--a costly alteration.

    The "Globe" silencer has been standard since 1917, and is a type which can be mounted on a vertical "stand pipe" of sufficient length to bring the silencer above the water line. It can be fitted to all Old models, and is recommended wherever the conditions described in paragraph 25 are not realised.

    Air valve washers were at one time made of red fibre which shrank and allowed the stem to slack back. They are now of brass and shaped like a horse shoe so that they may be inserted without removing the carburettor.