3GM30 Locked ?

[capngeo]

A buddy called, his Yanmar ran fine a few weeks back. Went to the boat today and no crank.. Said the batts were ok, saw smoke from the solenoid. I had him put a wrench on the balancer to see if it turned over... No

Had him remove injectors and dip the cyls for water.... Nothing

Told him to try wd-40 overnight, then try wrench in the morning. Any other ideas short of pulling the head? He has limited tools and experience, and I am 350 miles away from the boat.

[neilpride]

There is oil in the pan?? Gearbox in neutral?? nothing fouled in the prop, maybe starter bendix stuck?
Me? i take of the starter, Injectors, put the wrench in the pulley at the cranshaft, remove the valve cover, and see if there is litle movement, and see if there is rest of oil at the valves and cams , if there is oil in the pan , is very weird that a rod or the cranshaft seize, a piston maybe, you say no water in the cilinders??
Idk mate, good luck ...

[capngeo]

Yeah had him look for oil too... Black and full

Good thought on the bendix... Didn't think of that

Trans in neutral

[Cheechako]

no water in cyls...then I say a locked starter.... which may be good news!

[phantomracer]

crack the high pressure lines on the fuel injectors.

can the crank be turned with a breaker bar? Don't know if a wrench would have enough leverage to turn the crank.. a breaker bar would work better.

crack the injectors to prevent the motor from starting..in case there is no problem!

also, flip the decompression levers on the valve cover to make it easier too

at least that will eliminate a seized engine..and would point to a bad starter

tighten the high pressure lines after you are done.

[roverhi]

The 3gm30 has compression releases on the cylinder head. Look for small levers on the side of the valve cover. Lift them up to compress the valve and release compression.

Might try actuating the compression releases then use jumper cables direct to the starter bypassing the solenoid. That will tell you whether the starter is working. Can't help with more trouble shooting if there is no water in the cylinders. Don't try and start the engine by getting it rotating and then dropping the compression releases. If there is water in the cylinders, you'll ruin the engine doing this. If you are going to turn the engine over for any length of time with the starter, close the cooling water seacock. Failure to do this can result in the muffler filling up with water and backflowing into the engine.

[capngeo]

All the above has been done, in fact in post #1 you'll see I had him REMOVE the injectors! I need to touch base with him today to see if the wd40 worked

[capngeo]

UPDATE this is a C&P of a text he sent:

Starter not locked (is off)
Oil is normal
Head off and cyl walls are fine
Trans is disco’d at output flange. Won’t turn either

Anyone hazard a guess why the trans is locked too... in neutral? I’m thinking the motor has to come out and the trans dropped... he may have been barking up the wrong tree all along.... at my urging

[daddle]

One can turn a 3GM30 nearly by hand. Certainly with any wrench. If it was the transmission, injection pump, camshaft or starter there would be some small bit of play in the crankshaft...not frozen hard...I would think. Frozen hard points to crank bearings, rod bearings, pistons.

Sounds expensive. I'd pull the engine out. Maybe just one bearing burned up.

[capngeo]

Originally Posted by daddle

One can turn a 3GM30 nearly by hand. Certainly with any wrench. If it was the transmission, injection pump, camshaft or starter there would be some small bit of play in the crankshaft...not frozen hard...I would think. Frozen hard points to crank bearings, rod bearings, pistons.

Sounds expensive. I'd pull the engine out. Maybe just one bearing burned up.

But again... the trans is in neutral, yet does not turn at the output flange... I suspect the trans went south and is holding the crank from turning

[daddle]

Oh, I hadn't seen that post. That is indeed odd. Same cure...out comes the engine and wallet...

[neilpride]

Ouchh!! ok, head off, oil ok, couplings off, and the dam thing dont turn?? well i see you answer yourself, Trany Kaput!! good idea to pull the transmision out, i believe the engine is fine , good luck!!

[Maxs]

About a month ago, a same thing happened to a friend on his Perkins prima m50. Seize engine, no crank, but it was weird that the transmission was seized too, so he took out the tranny first, and the engine was ok. It turned and started as nothing have happened. Turned out that one of the ball bearings on the transmission turned into pieces and got stuck. So, tart by removing the transmission. That should be it. ....

[Kapena]

I once pulled a frozen engine. Couldn't find anything wrong. Upon re-installation found it was the transmission that was locked. Just saying....

[capngeo]

OK... finally got to KW to eyeball the boat myself...
Trans is fine
engine is locked, pulling it tommo