Now that I killed the 3gm30
 

I have to decide what to do next. My choices are:
1. Purchase a new 3ym30.
2. Purchase a "remanufactured" 3gm30 from Mack Boring
3. Rebuild mine (think least attractive as don't know how much damage there was from my hydrolocking crime, know that at least there is a bent piston rod).
4. Upsize with new 3jh4.

Boat is a freedom 38 which is a little big for the 3gm30 that has pushed it for 20 years.

Anyone have experience with remanufactured units? Anything to watch out for?

Awaiting pricing on the alternatives from the yard but didn't know if there were non-financial consideration to weigh.

Thank you for your help and advice.

Ed,

How did you hydrolock it? Are you sure you bent a rod? I have fixed a number of hydrolock situations and have yet to encounter a bent rod, but know it is certainly a common occurrence when you hydrolock an engine.

Have you gotten the water out of the cylinders, and oil, and tried to run it? If the engine was in otherwise good condition a rebuild might not be bad but a new short block might be less if they'll sell you one..

Sorry to hear about your issue..

I killed it
 

Maine;

The yard hand turned the crank and showed me that #3 didn't go all the way to the top of the cylinder. Something is certainly bent. It also has a "hard spot" when it turns.

How did I do it? I couldn't get it started and even though I shut off the water intake I probably didn't do it soon enough. Then I thought it was about to start and I opened it up again, that's when it gave up the ghost. Thought it was a burned out starter but no, water in the cylinders.

Dumb, dumb, dumb.

Waiting to hear from Mack Boring if they have a remanufactured short block.

Thanks for the note.

I just re-ringed my 3GM30F. It was neither difficult nor expensive. Runs like a top now. Also wound up hydro-locking once a few years ago but did not bend a rod. It's a common situation with these below exhaust installations. Unless you cannot get up to hull speed, there's really no reason to increase horsepower--just a waste of fuel. I think my re-ring, without a rod, cost around $400 for a new ring set and gaskets, considerably cheaper than a new motor. Did all the work myself and was able to drop the pan right in the boat so did not even have to disconnect the shaft.

Why would you need a new block? If a rod is bent, it does not necessarily do any damage to the block or liner. You should look-see before you spend $ on a block. You know the old saying, "If it ain't broke, don't fix it."?

Marion? You're not at Richie's (AJ) are you? He knows his stuff.

What did you do about the surface of the cylinders themselves? Did you hone themm to get rid of any glaze?........i2f

Yes. The reason for the re-ring was cylinder glaze and frozen rings. The engine, with only 70 hours on it from the previous owner, sat for 6 years and the rings had never really seated. The Yanmar tech guys thought the long sit in one position probably caused the problem. I carefully protected any grinding debris from falling onto the crank and used a 3 stone hone to break the glaze and cross-hatch. It did a really nice job. Of course w/ only 70 hours there was NO ridge. Yanmar recommends a ball hone but I have always used a stone hone and like them better. I was able to use a large mirror in the bilge to see the lower end to loosen and later re-torque the rod journals. Ran her all this last summer with no excessive oil use or any exhaust smoke. Before this she was burning a quart in an eight hour run!

Thanks for the great reply.......i2f

Yes..went the route of rebuilding our 3GM30F by Mack Boring and installed by Oxford Boat Yard in Md. If you're interested in details contact me off list. It was both an eye opener as well as a nightmare..enough said...

Not enough said for me! Can you at least give a summary of your experience here? This stuff is useful for all.

Would it be best to always start a diesel with the raw cooling water valve shut until the engine starts (to eliminate chance of hydro lock), or will this lead to unessary wear on the raw water pump?