5.0 Merc Dead Motor

[wewefirex2x]

I took my boat to the shop Monday. 1989 Monterey 5.0 GM 2 barrel carb Alpha One. The boat would not start for anything and when it finally did it had a miss. The mechanic said compression was 165 on all cylinders. I took him NEW carb,thermo. housing, water pump and fuel lines. Once all that was on the mechanic started the boat and found a miss. Once the valve covers were removed he found water in the heads. Pulled motor from boat to find out where the water was coming from and found a crack in the valve body. The oil at this point was like coffee.

How can a motor have good compression and still have a crack in the valve body?
Is it worth the money to repower a 20 year old boat with a Jasper?
Personally I would like to repower only because NO One will buy a land yacht.
The final price with the work that has been done and the repower will be around 5000 dollars! OUCH

 

[JustJason]

Re: 5.0 Merc Dead Motor

it's more than likely freeze damage

 

[wewefirex2x]

Re: 5.0 Merc Dead Motor

I was thinking the ame thing but when I winterized, I pulled the therm. housing hoses and watched for it to come out prop. Maybe there was build up in the block I don't know. What gets me is the compression. How can you have good compression with a cracked valve body? I don't know jack about the internals of a motor.

 

[Don S]

Re: 5.0 Merc Dead Motor

What's a "Valve Body" ?

All you need is a crack between a water and an oil passage in the block or the head. It doesn't have to be in cylinders.

 

[wewefirex2x]

Re: 5.0 Merc Dead Motor

Thanks Don. I guess what they mean by valve body is the upper section between piston and head???? I will be at the shop around noon today to make a decision.

 

[wewefirex2x]

Re: 5.0 Merc Dead Motor

Bubba, the crack was not in the head, it was in the #3 cylinder after I went up to the shop today. The engine would run fine until it got up to operating tempeture and that's when the mechanic heard a miss. Once the motor was pulled and the heads taken off #3 cylinder was full of water.

 

[wewefirex2x]

Re: 5.0 Merc Dead Motor

Remaned Jasper 5.0 with new exhaust manifolds and risers $4000.00
Labor already invested since it's been in the shop $1200.00
Owning a boat... Priceless

 

[tmh]

Re: 5.0 Merc Dead Motor

It sucks when you put far more $$$ into your old boat than it's actually worth (I think i passed that threshold this year also). I'd check Craigslist or the like for any rebuilt local engines for maybe $1800 or so - I got my Mercruiser 350 Mag for $1200 and it works fine - don't see many that cheap though). Also, why not throw a 5.7L in there as long as you're changing engines? Unless of course you had all the speed and power you wanted with the 5.0L.

Good luck, if "misery enjoys company", as they say, I'm sure you have plenty of company on this board that's been in the same crappy place as you are!

 

[wewefirex2x]

Re: 5.0 Merc Dead Motor

tmh, at this point it is personal. I bought this in 2006 as a hobby to tinker with. The tinker toy has turned into a tonka truck as far as money but whos counting. I can't keep track. The reason I am using the mechanic to replace the motor is because of the warranty. Yeah I could put the 350 my brother has lying around but then I would have to spend more to change out all the parts the I had bought over the winter for the motor that was already installed (that cracked).

 

[Don S]

Re: 5.0 Merc Dead Motor

I bought this in 2006 as a hobby to tinker with.

If you buy a boat to tinker with as a hobby, you DO NOT take it to a shop for repairs, you should be tinkering with it instead.
What you have done is bought a boat as a hobby and a way of getting rid of the excess funds in your checking account

BOAT = Break Out Another Thousand

 

[chiefalen]

Re: 5.0 Merc Dead Motor

No junk yards around there got a block?

 

[wewefirex2x]

Re: 5.0 Merc Dead Motor

No junk yards around there got a block?

The reason I am using the mechanic to replace the motor is because of the warranty.