Engine replacement

[Bruce 2nd]

Hello everyone. Welcome to boat ownwership as they would say. Purchased my first boat and after a couple uses I believe I had a hydrolock In cylinder 6. Compression tests revealed only 85 psi on cylinder 6 and the after further tear down to find my engine knock I've discovered a bent connecting rod where the piston skirt was coming down a tapping the crank. That's the least of my worries as I've also discovered one of the starter bolts was just about sheared off as the block cracked partially on the outer weaker bolt hole. What course of action would you guys go? Rebuild our just replace? No marks on the valves or piston so it appears the heads are fine. Get a new block and replace one connecting rod, new bearings and gaskets? I know for sure I probably need exhaust shutters to prevent this from happening again. Boat ran all day perfectly fine, came back the next day and backed it in the water and surprise. Boat is a 1992 wellcraft 4.3 mercruiser with the alpha one outdrive.

 

[Bondo]

Ayuh,..... Welcome Aboard,..... The wisest way to go is to buy a Long Block replacement, 'n use the accessories from yer old motor,.....

By the time you buy a block, 'n con-rod, then have the required machine work done, you can buy an already rebuilt Long Block,.....

 

[Searay205]

what caused the hydro-lock?

 

[Scott06]

Check your manifolds and risers for leaks. They are a common hydrolock cause as well, do not want to transfer them to a new long block. a complete base engine or reman long block is your best bet.

 

[tpenfield]

Welcome to iBoats . . .

Isn't boat ownership fun ???

I'd go with a new 4.3L long block replacement, as @Bondo said. (He knows this stuff) It can be hard to tell what gets damaged during a hydro-lock and what does not.

Since a bunch of boats in the southern USA states are in need of engine replacements this year (due to the unexpected freeze this past winter), engine replacements of all types are going to be in short supply. Do the best you can.

 

[Bruce 2nd]

Haha. Exactly! Real fun! Thanks for the help everyone I really do appreciate it. So replace the block, transfer stuff over. Get new gaskets and bearings, replace the starter ring on the flywheel due to the sheared off teeth, replace the bent connecting rod and all the rings and check over the heads is one possible option. Where would you guys go to get a new block? I see a big 756 on the side of this block but no serial number. I was also wondering the same thing, how did the water get in there? Shutters in the y pipe possibly when I backed the boat down the ramp to start it? Leak down from the risers or manifolds? I'm guessing to properly check the manifolds they need pressure tested or am I wasting my time there? I see kits with new risers and manifolds for around $900. If I go new who would you go to? I see jegs has new long blocks for around $1800-$2800.

 

[Bondo]

Ayuh,.... Go with a Long Block,.....

Doin' a bare block is a fool's errand,....

 

[Bruce 2nd]

Appreciate you. Any particular place you would go to order one besides jegs?

 

[Bondo]

Ayuh,.... Michigan motors has been used by many posters here,....

 

[Searay205]

You would a complete fool to install a "new" block without brand spanking new manifolds and risers unless you are 1000% sure how old they are and you bought and installed them

 

[tank1949]

4.3s and 5.7 are common or were common. If salt water cooled motor and over 6 years old, I'd replace motor. But, first find where water is leaking in. I suspect failing risers or shutters? However, I experienced a rusted out head water passage. The "cancer" ruined a v8.

 

[todhunter]

Just be aware if you are looking at Jegs...their lead times may be deceiving. I bought a long block in March/April from them with a posted 1 week lead time on their website. After 2 weeks I called them and they said it would be 2+ months. I got my money back and decided to just rebuild what I have. As said, engines seem to be in short supply right now...

 

[Paintman1960]

Check your manifolds and risers for leaks. They are a common hydrolock cause as well, do not want to transfer them to a new long block. a complete base engine or reman long block is your best bet.

Just be aware if you are looking at Jegs...their lead times may be deceiving. I bought a long block in March/April from them with a posted 1 week lead time on their website. After 2 weeks I called them and they said it would be 2+ months. I got my money back and decided to just rebuild what I have. As said, engines seem to be in short supply right now...

Yes, Jegs is in trouble
I would call Michigan Motors
Great to deal with!

 

[Bruce 2nd]

Thanks for the input guys. I’ll just replace everything to be safe. Guess it’s a waste of time to pressure test the stuff if It’s over 6 years old which I’m sure it is. New long block, new manifolds and risers to be safe and new shutters. All in all I might as well due the gimble, bellows, and u-joints while the motor is out as well. Be a damn shame I get the new motor in and then that fails next. Owning a boat is amazing when they work. I can see why other people told me to just buy new. I’ll still be way under 30k for the boat I wanted but damn what a head ache.

 

[tank1949]

Thanks for the input guys. I’ll just replace everything to be safe. Guess it’s a waste of time to pressure test the stuff if It’s over 6 years old which I’m sure it is. New long block, new manifolds and risers to be safe and new shutters. All in all I might as well due the gimble, bellows, and u-joints while the motor is out as well. Be a damn shame I get the new motor in and then that fails next. Owning a boat is amazing when they work. I can see why other people told me to just buy new. I’ll still be way under 30k for the boat I wanted but damn what a head ache.

You are just getting started. LOL! OB are the easiest to maintain but MCs and their parts are much cheaper, if you do the work yourself. If I had 60K lying around to waste on boat motors, I would have purchased 2 300 HP Yamie 4 strokers for my vintage Sea Ray build..

 

[OllieC]

Thanks for the input guys. I’ll just replace everything to be safe. Guess it’s a waste of time to pressure test the stuff if It’s over 6 years old which I’m sure it is. New long block, new manifolds and risers to be safe and new shutters. All in all I might as well due the gimble, bellows, and u-joints while the motor is out as well. Be a damn shame I get the new motor in and then that fails next. Owning a boat is amazing when they work. I can see why other people told me to just buy new. I’ll still be way under 30k for the boat I wanted but damn what a head ache.

I tell the Admiral that this is my 'Harley' or 'Hot Rod'. It's a 'Labor of Love' and satisfaction when you can do things yourself. (with the help of others input of course)

 

[Bruce 2nd]

All exhaust shutters were in place and seemed to function fine. There was a small amount of corrosion in the manifolds and risers but nothing to crazy. I'm guessing the risers or manifolds leaked down onto cylinder 6. Replacing the manifolds and risers anyway. Ordered the long block and everything now it's just the waiting game.

 

[Scott06]

All exhaust shutters were in place and seemed to function fine. There was a small amount of corrosion in the manifolds and risers but nothing to crazy. I'm guessing the risers or manifolds leaked down onto cylinder 6. Replacing the manifolds and risers anyway. Ordered the long block and everything now it's just the waiting game.

those shutters look fine. You must have had water in through the carb or the exhaust.

Maye sure you check out your intake manifold for corrosion and cracking in the water crossover (under thermostat) that wouldnt lead to water in the cylinders but rather in the oil. Now is the time to change it if needed.

 

[Bruce 2nd]

$3148.40 from Michigan Motorz and at my door in 6-8 weeks. I'll get $300 back once they get my core. Thanks again guys for the heads up as Jegs said shipped by 6-8 but when I called they said 4-6 months!

 

[tank1949]

All exhaust shutters were in place and seemed to function fine. There was a small amount of corrosion in the manifolds and risers but nothing to crazy. I'm guessing the risers or manifolds leaked down onto cylinder 6. Replacing the manifolds and risers anyway. Ordered the long block and everything now it's just the waiting game.

get you some acetone, plug risers and manifolds and test for leaks. If no leaks, I suspect head corroded like mine did and hydro-ed your motor.