Logo
FULL SITE MENU

Opinion on buying a non running 5.7

P

ptscon

New member
I'm considering buying a non running boat with a 5.7L motor, it's an early 90s.

Current owner says it ran fine but one day on the water, after stopping for a while, it would not turn over. Apparently a mechanic had a quick look and found, fresh, water in the engine but said the engine will turn over. I'm guessing it was hydrolocked but once sparks were removed it would turn over.

I don't think it was a winterising issue since it happened in late summer.

What kind of a mess would I get myself into if the price is right (cheap)?

I have experience in rebuilding high revving 4-stroke marine motor but zero experience with these big inboards.
 
if you don't know that it was stored properly, best to treat the engine as a core and nothing more.....if it is in a region subject to freezing, I'd avoid it unless the hull is immaculate and you wanna spend time working on it....and then treat the engine as ballast....
 
It's fresh water but the failure occurred several weeks ago. I'm just exploring the possibility with this, it may not be a good idea.

If we were to assume the mechanic that had a quick look at it got water out of the cylinders and/or fogged them somehow what scenarios could have occurred to cause the failure of water getting into the motor.
 
cracked manifold or riser, leaking gasket joint, shutting the key off with forward boat motion to get water shot up the exaust pipe, excessive people sitting on the swimplatform, to name a few
 
I wouldn't touch it unless the heads were first pulled to inspect the bores and see if there's a cracked block. The block cracks just bellow the heads when there's freeze damage so you can check it at the same time..

Jeff
 
If it had water in the bores, any mechanic would immediately pull the spark plugs and relieve the pressure. Then they would run the engine and go thru several oil changes. Once that was completed there would be a compression and leak-down test performed. If none of this engine-saving procedure was undertaken then you are looking at replacing the engine just because it is so suspicious. I personally wouldn't leave the dock with such a sketchy motor determining my fate.
A replacement block is about $2500. I have doubts that this boat you are considering would be worth that kind of coin right off the bat. I suggest that you find a more reliable boat. Don't be taken in by cheap. Cheap boats are never cheap. One way or another they cost you.
If the seller takes such awful care of the engine after a severe event like water ingress (which I don't believe...I think it has a cracked block) then you have to wonder about all the other systems.
 
The first critical thing is draining the water as fast as possible and getting the motor running to dry it out.
The longer it sits the more damage is done. Once thats done change the oil and filter and run the motor under load for around 2-3 hours baking all the moisture out of the motor. What is most vulnerable are the valves sticking in the guides but if you run it for a few hours it should be ok.
fog the engine very heavily at end of season.

if you interested in a good boat and close enough v6 SR 220 CC pm me for info
 
Last edited:
ptscon said:
I'm considering buying a non running boat with a 5.7L motor, it's an early 90s.

Current owner says it ran fine but one day on the water, after stopping for a while, it would not turn over. Apparently a mechanic had a quick look and found, fresh, water in the engine but said the engine will turn over. I'm guessing it was hydrolocked but once sparks were removed it would turn over.

I don't think it was a winterising issue since it happened in late summer.

What kind of a mess would I get myself into if the price is right (cheap)?

I have experience in rebuilding high revving 4-stroke marine motor but zero experience with these big inboards.
Click to expand...


Save your money. Don't buy anyone's junk. And it is junk.
 
I did a similar project two years ago on a 2004 Sea Ray 200 that previous owner cracked block. Where it made sense to me was boat was in really great shape and only had 38 hrs on it, most importantly by the time I bought the boat and the new engine I was in it for half of book value.

I would think you need to approach as thought the engine is shot from a purchase price standpoint. By the time you fix it to O2s point the boat probably isn't worth it. You can probably find a similar vintage running boat for similar money to the cost of repair...
 
That at least!

We absolutely lucked out buying a 30 year old bowrider with a Mercruiser and it works super. Had to replace a few things, but the motor, trim system, OD, etc. runs like new.

Jeff
 
Back
Top