just put my ysm12 back together, turns out the valve adjustment was the thing that prevented it from starting! Has to be on the compression stroke. Anyway, am sooooo happy that my engine runs, and am looking forward to making it look as good as it runs and putting it back in the boat. Traded my 22 footer for this 30 foot fixer upper, and am looking forward to the maiden voyage! Anyone looking for a tip on ysm12 rebuild info, just ask, will be glad to share the info.... happy sailing fellows!
YAY! got ysm 12 running
- Thread starter aussiejay
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AussieJay,
I have a Yanmar YSM12. It came with a boat I just bought. I was told the engine was a rebuild and it looks like new, fresh paint, new starter ect but it won't start. It has set in storage for at least 4 years, I have no idea how much longer. The fuel is fresh and no water in it. It seems to have adequate compression. Fuel comes through readily upon cranking to the feed side of the injector pump. Very little comes out the high pressure side. How much should be expected at cranking speed? A few drops or a strong squirt? I get a few drops, I expected a strong squirt. Supposedly the injector pump is a rebuild. I took it apart and it seems to be in proper order. The parts function as in the repair manual, valve slides easily. No scores or wear spots, springs are not deformed or broken. I reassembled and filled it with WD40. Off the engine and by depressing the follower cam against a wooden work bench, the output side still only gives a feeble drop or two with each depression. Other then that, the engine will not fire or even sputtter with WD40 sprayed down the throat or a short blast of ether. This concerns me since I have never had a diesel, or any other engine, not light off with a blast of ether. I have a diesel mechanic coming to look it over but would appreciate any insight you may be able to provide.
Thanks,
M Cosnett
I have a Yanmar YSM12. It came with a boat I just bought. I was told the engine was a rebuild and it looks like new, fresh paint, new starter ect but it won't start. It has set in storage for at least 4 years, I have no idea how much longer. The fuel is fresh and no water in it. It seems to have adequate compression. Fuel comes through readily upon cranking to the feed side of the injector pump. Very little comes out the high pressure side. How much should be expected at cranking speed? A few drops or a strong squirt? I get a few drops, I expected a strong squirt. Supposedly the injector pump is a rebuild. I took it apart and it seems to be in proper order. The parts function as in the repair manual, valve slides easily. No scores or wear spots, springs are not deformed or broken. I reassembled and filled it with WD40. Off the engine and by depressing the follower cam against a wooden work bench, the output side still only gives a feeble drop or two with each depression. Other then that, the engine will not fire or even sputtter with WD40 sprayed down the throat or a short blast of ether. This concerns me since I have never had a diesel, or any other engine, not light off with a blast of ether. I have a diesel mechanic coming to look it over but would appreciate any insight you may be able to provide.
Thanks,
M Cosnett
I have a YSM 12 that did have starting trouble before rebuild. The YSM 12 depends on compression for ignition. There is no glow plug. One method that I used successfully when the engine was hard to start was to blow hot air from a blow dryer into the air intake while cranking. The old engine would fire every time, even when the compressions was very low, with a blow dryer in the air intake.
The high pressure fuel pump puts out a very small amount of fuel. Be sure you purge the fuel line all of the way to the injector.
There are a number of potential reasons for hard starting diesels. Torresen Marine has a forum on diesel engines that was very helpful to me when I was trouble shooting my hard starting problems. Here is the link. http://forums.torresen.com/sailing/viewforum.php?f=2&sid=dc6f7c78753f355d5f048230f0278efa
The high pressure fuel pump puts out a very small amount of fuel. Be sure you purge the fuel line all of the way to the injector.
There are a number of potential reasons for hard starting diesels. Torresen Marine has a forum on diesel engines that was very helpful to me when I was trouble shooting my hard starting problems. Here is the link. http://forums.torresen.com/sailing/viewforum.php?f=2&sid=dc6f7c78753f355d5f048230f0278efa
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