1984 Mercruiser 5.7L Alpha One Engine Problems

Dsvictorious

Recruit
Joined
Nov 19, 2009
Messages
2
Problem?
I had my boat in the water about two months ago and after a haulin butt secession down the river I noticed that my temp was about 260 on my gauge. I immediately cut the engine off and waited for it to cool. I drove to the marina very slowly in fear of a blown head gasket. I got to the marina and the next day I replaced the thermostat. ( thinking that it was a thermostat sticking) The next day I took the boat out and I had high temp again and loss of power. Hard start ups and rough idle while on the water. I immediately went back to the marina. I checked the transom and found that the water intake vent on the transom was severely riddled with barnacles.
Later on that week, I checked the oil and found coffee like substance on dipstick and valve cover. I pulled the plugs and found corrosion on the right side plugs and wires and water in the cylinders. I additionally found that my risers and manifolds were leaking.

Compression test shows loss of power on that side.
Blown head gasket?
New risers and manifolds?
New engine?
Rebuild engine?
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,343
Re: 1984 Mercruiser 5.7L Alpha One Engine Problems

i would say all of the above

pull the heads and inspect

sounds like you severely overheated the sucker once and probably twice
 

Dsvictorious

Recruit
Joined
Nov 19, 2009
Messages
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Re: 1984 Mercruiser 5.7L Alpha One Engine Problems

what are the odds of a cracked head?
We winterized it last week and this in my happy new spring project :mad:
 

crazy charlie

Vice Admiral
Joined
May 22, 2003
Messages
5,636
Re: 1984 Mercruiser 5.7L Alpha One Engine Problems

I would say the odds are high that it is cracked.Pull it and get it magnafluxed if it looks good.Charlie
 

intrepidvoyager

Petty Officer 1st Class
Joined
Mar 24, 2009
Messages
216
Re: 1984 Mercruiser 5.7L Alpha One Engine Problems

DON'T wait to get the heads off ...... if you have water in the cylinders in a few days you will have rusted the bores and you will need a new block !!!

why a new block ..... cause a rebore / rebuild costs more .
 
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