low compression on #1 cylinder

gwgautney

Petty Officer 1st Class
Joined
Aug 28, 2013
Messages
283
just picked up a boat with a 1987 Merc 60 SN 0b17115 and I think last number was 0 couldn't read it good. It only has 30 psi on #1 and 120 on 2 and 3. There is some sort of white looking build up on the plug out of number 1. I wanted to see if anyone could tell me what my issue may be. Guy I got it from said he ran it hot and it shut off. He said he ran it at home on the hose but only at idle. Didn't know if this could be head gasket or worse and also what I would need to do to check
 

dpeslinger

Seaman Apprentice
Joined
Mar 23, 2013
Messages
37
Re: low compression on #1 cylinder

white color on the spark plug indicates water in the cylinder. sorry to be the bearer of bad news.
 
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racerone

Supreme Mariner
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Dec 28, 2013
Messages
39,164
Re: low compression on #1 cylinder

There is no head gasket on that motor.----Remove the cover on the starboard side to have a look at the pistons and rings.-------But it does not sound good.-------Tear down and overhaul time !!
 

gwgautney

Petty Officer 1st Class
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Aug 28, 2013
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283
Re: low compression on #1 cylinder

I bought motor, boat and trailer for like $300 just really to flip it. What kind of cash am I looking at to overhaul doing it myself?? Never had to do one. motor is clean as a whistle I believe its worth doing just don't know what kind of money I want to sink into it.
 
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gwgautney

Petty Officer 1st Class
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Aug 28, 2013
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283
Re: low compression on #1 cylinder

also where can I get a service manual
 

MikDee

Banned
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Jun 6, 2007
Messages
4,745
Re: low compression on #1 cylinder

You have to crack open the powerhead, and take everything out from the crankcase side to work on it, or rebuild. No Fun! Many yrs ago, I was stupid enough to rebuild a 70hp "tower of power" 6cyl. inline, plus put heli-coils on all the spark plug holes, because they were stripped, Never Again! :eek:
 

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: low compression on #1 cylinder

A mercury manual can be bought at some dealers or a call to Mercury Marine. Ebay has some at times and a Solas manual can be bought here on Iboats. Rebuilding the motor can be done, but there are some things that will need to be done by a machine shop. The best bet is to find another motor with a good power head and bad LU and just switch the power heads, or buy a rebuilt power head. Most any way you go is going to cost big $$$. Buying a good used motor might be cheaper in the long run, if you want it quick. JMO
Oldman570
 

gwgautney

Petty Officer 1st Class
Joined
Aug 28, 2013
Messages
283
Re: low compression on #1 cylinder

may just part motor out or sell it like it is see if someone else wants to tackle the job lol
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,936
Re: low compression on #1 cylinder

The "white stuff" is aluminum throwoff from piston meltdown, usually leaves a impression of sparkplug,
 
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