Using Valve Lifter To Help Starter...?

[gjordan]

Bails out, it sounds more like an air leak to me. I would check all of the fittings in the fuel system for tightness. It could (hopefully not) be the seal in the injection pump that allows a tiny bit of air in. If it starts OK after bleeding, then that is a big sign. Does your manual show a cold start button, or a particular throttle setting for starting? The other chance is low compression. Try a space heater for an hour or more, to bring the temp up, and see if it starts easy. It is possible to have low compression, and not burn any oil. You mentioned 30 hours since rebuild, if that 30 hours has been mostly at the dock at idle, you might have glazed cylinder walls. A fresh rebuild is much more likely to glaze than an already broken in motor. If you have low compression indications, then take it out and run it hard for as many hours as you can, and see if that improves the starting. Another chance ,since the last owner said it always started hard, is that the rebuilder set the injection timing a little off. It could still seem to run fine, but be hard to start. Dont burn up your starter motor from running it too long. Good Luck, and keep us posted when you figure it out. _____Grant.

[charliehows]

bailsout - i've replaced; fuel tank supply taps, all hosing, main fuel filter, engine lift pump, small final filter ; all at one time or another have caused small air leaks which stopped the engine. Once these old engines have a guaranteed fuel supply they start and run very well indeed. most of the fuel system ancillaries are quite cheap to replace and its worth doing it as a job lot on an engine up to 30 years old. At least consider replacing any of them that you dont know have been replaced at some time - those bits just dont last 30 years or so like the rest of the engine will.
On the valve lifter - ive pretty much incorporated it into the start procedure now - one of the benefits being i only need to use one battery where i was regularly using 2 before. Im still going to pull the starter to check the commutator and brushes though but for the moment 'if it aint broke...'

[bailsout]

Thanks again for the help. Today i started the engine by heating up the injectors with my heat gun and pumping the mechanical fuel pump with its lever. Decompression engaged I cranked it with the starter motor a few times to spread some oil around. As I compressed now with the cable back in, the engine began to catch,though reluctantly, until I started backing off the throttle and it then began to run strongly. The process left a little trace pf diesel on the ocean's surface but that quickly stopped. Has my problem been nothing more than trying to start it with too much throttle? I'll try again tomorrow without heatgun and less throttle.

[Neo]

Originally Posted by charliehows

bailsout - i've replaced; fuel tank supply taps, all hosing, main fuel filter, engine lift pump, small final filter ; all at one time or another have caused small air leaks which stopped the engine. Once these old engines have a guaranteed fuel supply they start and run very well indeed. most of the fuel system ancillaries are quite cheap to replace and its worth doing it as a job lot on an engine up to 30 years old. At least consider replacing any of them that you dont know have been replaced at some time - those bits just dont last 30 years or so like the rest of the engine will.
On the valve lifter - ive pretty much incorporated it into the start procedure now - one of the benefits being i only need to use one battery where i was regularly using 2 before. Im still going to pull the starter to check the commutator and brushes though but for the moment 'if it aint broke...'

Charliehows, I am no expert, but my 2GM20F and I have developed a close relationship over the past few years.

I don't see a problem with using the decompression lever when starting, however you should not need to use it. And as roverhi said, if there is water backed up in the exhaust system, using it may allow water to flow back into the cylinder on the intake stroke.

I think the first two responses you got were correct. From my experience, roverhi and delmarrey know what they are talking about. I would question the the voltage/amp getting to the starter. It may be old battery cables, it may be bad batteries, or it may be the brushes.

Under normal circumstances, a small starter battery should have absolutely no problem turning these small engines over through many compression strokes, especially an older engine that probably has worn rings.

Also, are you sure the starter engages and the engine turns over then stops. These engines are know to have problems with the starter solenoid. My yanmar usually requires 2 or 3 pushes of the button before it turns over. See link below.

http://www.cruisersforum.com/forums/...ter-20150.html

[laika]

Originally Posted by charliehows

thought i'd try something new, turn key to on position and wait a minute - started first bang, no hesitation. Been doing that for the last couple of days, works every time.

I'm also not an expert, but I know my 3Gm30F pretty well. Based on this I would say electrical. Seems many Yanmar's are notorious for bad wiring. Mine had an intermittent starting problem for a while which ended up being a bad solenoid connection. Factory un-tinned wire. Upon further inspection, came to find all the wiring Yanmar had used was un-tinned. Also highly questionable trailer connectors. Only a ten year old engine clean and in great shape, but the wiring was disintegrating. Replaced it all. YMMV.

[charliehows]

yeah - the symptom is what generally happens if you have a loose connection to the solenoid because i've had that a few times before. Think i'll take a look at the condition of the wiring.

[roverhi]

If it will only start easily after bleeding the system, would seem that you have an air leak between the tank and the engine. Should only need to bleed the fuel system if you disconnect something like when changing the engine fuel filter.

I'm not a fan of the wiring on Yanmars. My 3GM30f wouldn't start after a haul out. No work done to the engine or even in the engine space. Turned the key and it was dead, jumped from the battery to starter solenoid and engine turned over. Yard electrician figured out there was an open in one wire inside the harness. The connections were good but somehow got cut inside the shrink wrapped harness though no sign of abuse to the cover. spliced in a jumper wire from where it entered the harness to where it exited and lived happily ever after, or at least for the last 5 years.

[sww914]

I concur with cleaning the cable connections. ALWAYS do the simple thing first. A kid that worked for me ripped out the whole wire harness in his Porsche and built a new one after I suggested that he check the basics first. The engine still had the same miss after the new harness that took him 24 hours to build.
I found the problem within 2 minutes, the rotor electrode in his distributor cap had digested it's self.

[charliehows]

Originally Posted by sww914

I concur with cleaning the cable connections. ALWAYS do the simple thing first. A kid that worked for me ripped out the whole wire harness in his Porsche and built a new one after I suggested that he check the basics first. The engine still had the same miss after the new harness that took him 24 hours to build.
I found the problem within 2 minutes, the rotor electrode in his distributor cap had digested it's self.

lol, my old mercedes died a couple of months ago - same problem - the gap between the rotor connection and (very burnt) cap electrode was over 1/2 inch! and she still kept running! mighty merc.

[bailsout]

Yesterday I began starting procedure without using heatgun. I still spun the engine a couple times decompressed then compressed. As it began to sputter and catch it ran more strongly with the starter button still held down and backing down the throttle. Seems like I have just had the throtle too open? I'll try again tomorrow.

[pbiJim]

A properly adjusted decompression system can be a beautiful thing. I used to own a 600cc single cylinder motor cycle. When I bought it, I could stand on the kicker & it would not move. After I tuned the decompression lever correctly, a single smooth gentile kick would start it just about every time.

The trick to adjusting most decomp systems is to set them so that you get enough free spinning time to get the motor inertia going, then kick it off just in time to make enough compression to spark up that first full compression stroke. On a cold diesel, that is usually about 80-90% of a full normal compression stroke. A little trial & error can help you to find the sweet spot.

If you need more than 1 or 2 revolutions of free spin to get good results on a diesel, than you probably have injection issues of some sort, &/or dead glow plugs.

Another possible cause of a starter not wanting to kick over a cold motor is fried windings in the starter. Many of the previously listed issues are more common on a boat, but this should also be considered as a possibility.

[bailsout]

No glowplugs on this Yanmar.