This is my first post but I've been a reader for a while, so thanks in advance - I've gotten lots of good tips/advice from these forums
I've got a Yanmar
4JH-TE that won't crank. It has never given us any problems, always starts first try. Has about 2800 hours on it. We were marina bound all this past winter (in Alaska) and I'd been running the engine
about a half hour every two weeks. Well, last month I got lazy and didn't so it hasn't been run in approx 6-7 weeks. It's last good workout was probably September when it was putting in 6-8 hour days between 2600-2800 rpms.
/ starter just makes a really loud "clunk" noise
. The crank pulley on the front of the engine turns 1/4-1/2". Engine's always in neutral when trying to start and the prop shaft doesn't move at all. Here's what I've tried thus far:
1- First thought was lack of battery
. My clamp amp meter maxes out at 400a and it reads "over" - e.g. 0.L (for anyone with the Mastech). Just to be sure, I also used an emergency
rated for 500a for 3 seconds, and lastly also jumpered in my 800 ah house bank. Same reading on the amp meter for all. The voltage does drop but given the loudness of the clunk and that the whole engine seems to shudder I'm thinking this is just abusive to the starter motor/gearing more than anything. Not to mention we've had a low start battery before and the engine turned over slowly in that case. Fairly certain it's getting plenty of juice.
2- Tried opening the injector caps (don't think there's decompression levers on this model engine) and also turning the engine by hand. I wasn't able to find a turning bar / breaker bar to fit, so I used a 5/16" hardened bolt with a 2' cheat pipe. The bolt goes in about 1/2" and I've bent it a few degrees trying to turn the engine by hand both clockwise and counter clockwise. I can't budge it at all (not even the 1/4" the starter motor
The only thing I can think of next is to pull the head
off, however I'm a bit nervous doing that - we're in a remote Alaska fishing
town and I don't think the local diesel mechanic
has much experience with Yanmars (going to talk to them on Monday anyway and see). I'm fairly mechanically inclined but haven't done any major engine work
before so am worried I could easily do more harm than good. I don't have a torque wrench but could get one - not sure what else I'd need.
One last bit of info - last year I started noticing a little bit more white/grey smoke than normal. It seemed to persist even after a full day of motoring (though was less than at startup). The general thinking at the time was everything from head gasket
getting in to something with the turbo to don't worry about it older diesels smoke.
looks good from the dipstick, no discoloration and has about 80 hours on it. Was going to change it anyway so that's what's in progress this afternoon.
Can I put something like PB-Blaster or ATF in the injectors to help loosen things up or would that risk more problems? (or do nothing- I gather it takes a bit of pressure to get anything through them?) Also I assume I've put enough pressure on the crank pulley with the bolt/pipe but to be honest I have no idea how much force it'd take to turn by hand since I've never done it before.
Any other suggestions greatly appreciated.