by Mike Harper
Not so much an engine, more a way of life!: Word reached me the other day on the Ionian branch of the international grape vine, (we are wintering at Nidri on the island of Levka), that the current owner of our old Zulu fishing boat "Rolling Wave" was about to replace her old Kelvin with a new motor.
Such a sacrilegious act has prompted me to write to him, and it occurred to me that my memories might provide food forethought, or at least some reading material for the heads.
The problem I imagine with Kelvin K2, No. 19194, or the Monster as he was better known, is that the new owner finds him difficult to start. This is not surprising, as to get him throbbing into life involves following a routine almost as complicated as the cockpit drill necessary to get a jet airliner into the air.
It also means understanding the principles on which he operates, plus making a real effort to get into his mind, for 19194 has a personality of his own. He will invariably misbehave if a female person should invade the privacy of his lair, known to most as the engine room.
The problem in getting one of these old Kelvins to start is that they must be hand started, and before you can attempt this you have to do a little oiling of the vital parts, engage the impulse magneto and make sure of the petrol supply. What is that you cry, Kelvins in old fishing boats are all diesel engines, why are you burbling on about petrol and magnetos.
This is why you have to understand exactly how they operate and then you will appreciate the technique for getting them started. Once running, as long as there is fuel in the tank you can guarantee that; a Kelvin will run for ever.
The usual generic term for engines of this type is "Old Thumpers" because they run at an incredibly low number of revs, about 100 rpm on tickover and maybe a reckless 75O rpm flat out.
To achieve this they are massively built, and it is the combination of hefty bearings and low revs which gives them their longevity. The penalty is that such engines are very heavy with a laughable power to weight ratio, and are also very Large.
The were ideal for the fishing boats of the time for which they were designed and also were very successful in powering barges, small tugs, pilot boats and the like, where reliability was the most important factor.
The K series included a one lunger, a two lunger, a three cylinder job said to be the smoothest runner, a four cylinder, and a six, all using identical parts.
Each pot was separate, so that pistons, con rods, heads, cylinder barrels, liners, valves, were all interchangeable between each model, and the essential difference was that the length of the crankcase was increased to cope with more cylinders and the crankshaft, and cam shaft, exhaust manifold were all made longer as required.
There were obvious advantages for a fleet owner in this, especially if different boats had different sized engines, as so many parts were common, simplifying the spares stock problem and reducing the inventory.
Kelvins also run with cylinders out of action, and on one occasion 19194 brought us safely home from Bologne and up the Thames to Shepperton, on one cylinder only, when a head gasket blew.
However I digress from my main point, which is how to start them. The first essential, (with 19194 anyway) is to put him in a good mood with a cheery greeting. "Good morning monster" always goes down well. Then proceed as follows:
1. Oil the three points on the water pump with the oil can. No oil gets to the bearings unless you do this.
Starting The Monster
2. Top up the wells on each cylinder. These contain wicks down which dribbles oil to lubricate the rockers.
3. Open the cocks on the petrol combustion chambers, (the rectangular boxes on top of the heads), and make sure the decompression lever is back.
4. Wind the engine round with the starting handle about 20 times to get the oil from the sump circulating and onto the bearings etc, and to loosen the pistons in their bores.
5. Prime the chambers, using a special gun, with about 6 to 8 squirts through the cocks.
6. Find the carburettor - the round ball at the after end of the engine, with a brass pipe feeding each petrol combustion chambers, and deliver two dollops of petrol into the gauze at the top. This ensures that there will be enough fuel when he is running on petrol. (confused? read on!)
If you use the brass petrol can supplied by the makers you get one dollop, (or gurgle load) every time you upend it, so this way you don't pour in too much or run the risk of running dry at a crucial moment.
If he is very cold and you think it wise to let him run on petrol for some time before trying him on diesel, you can top up with more gurgles while he is running.
7. Find the impulse magneto, which is port side, front, low down, and screw in the lever by turning it clockwise. This engages the springs and pawls on the magneto, so that later on, when you pull him over compression, the magneto will rotate rapidly, and at just the right moment, when the spring pulls it round. (If the timing is correct), and deliver a spark from the plugs on the petrol combustion chambers, so igniting the petrol you have already squirted into the chambers, and drawing more petrol from the carburettor.
8. Remove the earth lead from the magneto otherwise No. 7 will not happen.
9. Open the drain valves on the injectors.
10. Open the governor lever to a little more than halfway.
11. Make sure he is not in gear.
12. Now for the big moment - grasp the starting handle firmly, engage it and pull sharply over compression. Be not afraid. If the timing is right he cannot kick back. If he did he would possibly break your wrist, so that the first time you go through the routine after a maintenance job that required him to be re-timed is always an interesting event!
If you have made sure that the oil has circulated, it is not so hard to pull him over compression, providing you make a determined stab at it, and at the critical moment when you are just reaching top dead centre on a firing stroke (with a two cylinder four stroke engine you get two successive non firing strokes, before you get a firing stroke and then exhaust on the next revolution), a kind of loving nudge will take him over TDC.
Then there will be a sort of squashy bang when the spark generated by the magneto explodes the petrol you squirted into the petrol combustion chambers.
This bang will be followed by another bang from the next cylinder, and then a series of bangs settling down into a steady rhythm as he draws petrol from the carb and sucks in air so that he is running happily on petrol.
The explosions in the petrol combustion chambers pass down through the open valves (opened when you pulled back the decompression lever), into the diesel combustion chambers below, and shoves the pistons down. As long as there is petrol in the carb this will continue.
See later for what to do if he just sighs over compression and does not fire. Maybe if he didn't fire it was because you tackled the pulling over part hesitantly and with a lack of courage, to which he will respond by baulking, so it is worth one more go. If that does not work, waste no more time or energy: you will be flogging a dead horse.
13. Assuming success, let him run on petrol for 20 or so seconds, then close the drains on the injectors so that the diesel fuel is no longer all draining back to the governor, whence it finds its way into the fuel system, but instead squirts into the cylinders.
14. When he is banging happily away, and sounds eager, push the decompression lever forwards quickly. This will close off the petrol combustion chambers, bump up the compression in the diesel combustion chambers to a pressure which will ignite the diesel fuel, and lo and behold, there will be an almighty bang sounding exactly as if some one is trying to escape from inside the engine with a sledge hammer, followed by a hesitant lurch over the next stroke or so, then a more disciplined bang, then a series, until he settles down into a nice steady plonking rhythm.
15. When this point is reached, which should only be a matter of seconds, ease back the governor gradually until he is ticking over at about 110 rpm. This speed can be checked by counting the strokes that the water pump makes.
16. There is more to do before you take a rest. Screw out the impulse magneto, as if you don't it can be damaged.
17. Replace the earth lead onto its terminal.
18. Open the little drain cock on the side of the crank case just above the magneto. A slow steady drip-drip of oil indicates that the oil pump is satisfactorily distributing oil round the galleries. If there is no oil from this tap, stop the engine, as otherwise you can damage him.
19. Nip up on deck and check that water is coming out of the exhaust.
20. Pat the Monster on the flank (known to most people as the exhaust manifold), and if it is not too hot you know all is well. You can then thank him for performing well, and sit down for five minutes before you start heaving up the anchor.
1. Don't bust a gut continually swinging. All you do is to exhaust yourself. If there is petrol and a spark he must fire, so one or maybe both of those must be wrong.
2. Check that petrol is getting through to the chambers by unscrewing the nut on the bottom of the carb. The petrol will fall through two holes, so catch it in the priming bottle or can for reuse (and safety). Then with a special brass Kelvin tool, unscrew the jet. This sometimes will get blocked. If so clean it, replace, and give two more gurgles of petrol, and have another go. Don't forget to re-prime the petrol chambers as in No 5.
3. If you still have no luck, check the plugs, in the same way you would in a car or any other petrol engine. Remember that the mag has four terminals, one for each stroke of the engine, so you may have to turn over three revolutions to get to the one you are shorting out. The click at the mag indicates the moment when there should be a spark at the plug. The flywheel is engraved to show when the No 1, flywheel end cylinder is at TDC, (Ed. by opening the brass tap on the petrol combustion chamber, and turning the engine until air blows out of the open tap you can identify which is the correct firing stroke).
4. If the plugs give no spark at the mag, maybe the points need attention.
5. Another possible reason for not firing is the use of very old petrol, or even by mistake using paraffin or diesel in error.
6. Yet another cause for no action is that you have left the earth lead on. In this case, return to GO, and do not collect £200, and apologize to the Monster.
7. One other reason might be lack of compression due to a damaged head gasket.
Maybe you changed over before he was warm enough, or before fuel had reached the cylinders, or you forgot to close the drains. If the latter, you forfeit ten points and start all over again.
Apart from having a party to celebrate success, the following procedures must be followed.
1. Every hour go down and check the engine all over to make sure nothing is hotter than the hand can bear. Start at the stern gland, heat means the packing is too tight, then feel the thrust box, which needs occasional greasing at the nipple.
If the gearbox is hot it means either too much oil or too little oil, and there are no prizes for knowing how to check this.
The whole crankcase and sump should never be more than warm, the cylinders and heads should be cool enough to touch, and the exhaust manifold should be no more than tepid.
If any part is appreciably hotter than the rest it is probably getting clogged with salt, rust, dirt, or barnacles. The latter can even grow inside the cooling system of an engine, as happened with 19194 in Barcelona during 1969. Hands up if you knew that before.
2. Every two hours oil the water pump and top up the wells on the rocker covers.
If you want to idle for some reason and save fuel, once he is warm the Monster will run quite happily on one cylinder, which you achieve by opening one injector drain.
The resulting ponk-squeak, ponk-squeak, has been known to turn on the most unlikely people!
Ever 200 hours you need to make an oil change, this is a load of fun and laughs. The best way is to remove the covers on the side of the crankcase and bale out the old oil with a plastic can, ending up by wiping off every surface you can reach with a piece of good rag.
If you lie on your back with your head in the bilge it is possible to reach the under surface of the pistons, which seem to respond to having clean bottoms. The bearings and the cups on the connecting rods are by comparison child's play to get at.
If you have got the Monster running after having difficulties, you may well have an irresistible urge never to stop him again, but just let him ponk on for ever, topping up the fuel tanks now and again.
The state of exhaustion I reached in the Med when it took me five hours to start him is something I shall remember all my life.
The problem was that it was so hot in the engine room, that the petrol evaporated in the combustion chambers before I had time to get into the swinging position. Which in my case was best done on my knees.
Somehow adopting a kneeling, almost prayerful position when attempting to start him seems entirely appropriate. On this occasion I rubbed both knees completely raw, and could not swim or scarcely walk for a week.
However assuming you do want to stop him, and that rhythmic exhaust boom is so attractive that I can well believe that it will lull you into a hypnotic state where that is the last thing to appeal to you.
The procedure is simplicity itself. Open the injector drain no fuel no go, pull back the decompression lever, (some times referred to as the change over lever) and open the petrol priming cocks to help clear the cylinders of all gas and gunge, which may be harmful to the Monsters internal organs.
When he has sighed to a halt, a mournful and characteristic sound, evocative of all sorts of good things, then close the petrol cocks. Do not forget the pat on the manifold and a word of thanks for a good job well done.
I may have made some of this seem a little daunting. Certainly the starting procedure is such that you will not want to do it more often than is necessary, and to have to stop the Monster every time you enter a lock, only to have to start it again three minutes later is enough to deter you from a cruise up the Thames for example.
If you should risk this and a sympathetic lock-keeper does not insist on your stopping him, it is astonishing how people will flock around your boat, drawn by that magic exhaust boom, and that in its self almost justifies the aggro when the next lock-keeper is less understanding.
"First built in 1935", you say casually, been rebuilt a little since then of course. Marvellous engines really. Doing about 100 revs at the moment. What's that? Oh cruises at about 400 maybe a little less. Big prop of course, but these are genuine horses he is putting out. Yes its a Kelvin the two cylinder job. You want to go on board and have a look? Well of course, except I haven't polished him for a little while and you should really see him at his best. Excuse me the lock-keeper wants something"
"What's that? you want me to stop him, some kind of fire risk? You realize its a hand start engine? once it took me three days to get him going, yes I know he's warm now, that just makes it more difficult to pull him over compression. Oh, you'll tow me out if I have difficulties? All right then you unfeeling gentleman".
Against the cons of excessive weight and mass and a starting routine which is in fact not quite so traumatic as I have made it sound but is still a long way from a push button modern job, you have the pros of an economical and reliable engine, whose life expectancy is infinite if looked after.