150HP 1987 #1 Cylinder is Fouling the Plugs HELP

woodcutter43

Recruit
Joined
Jul 5, 2007
Messages
3
Hi just did rewire most of the engine with new wires. Hooked up the trim & tilt and the plug for the throttle control and steering. Went out on the lake, ran fine for a little bit, then the engine started to foul. I found the spark plug for the #1 cylinder was fouled with what looked like little metal flakes or a white grayish powder. I changed out the spark plug from another cylinder #2. Then tried to run it again. The #1 cylinder fouled again.

To repair this I gather I have to remove the heads, and all that front plates. How hard of a job is this. Can anyone send me a copy of assembly diagram? Everything else is running fine on this motor. Suspect lower motor pump might not be pumping enough water up to the cylinder heads, is this possible?? Thanks Josh
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: 150HP 1987 #1 Cylinder is Fouling the Plugs HELP

Wood, if you still have good compression in that cylinder, maybe you can save it. I think you are getting the metal flakes from too little lubrication, and/or too little cooling. i would first replace the water pump impeller (or test the water pressure to see if it within specification). I would definately clean the carbs(all three).

You are going to need a service manual to do this job.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: 150HP 1987 #1 Cylinder is Fouling the Plugs HELP

Lean fuel mixture in one barrell can cause this also.
 

woodcutter43

Recruit
Joined
Jul 5, 2007
Messages
3
Re: 150HP 1987 #1 Cylinder is Fouling the Plugs HELP

Hi, again,
Checked the compression on all the cylinders. The #1 has 70. The others have 100. What should the compression be?? Haven't pulled the lower unit to check the impellor. How hard is it to get to the cylinders and pistons???
Does anyone have a copy of the information on doing this? Or a copy of the pages I need from a service manual? Can't find anything around here.

Should this motor be saved with such a low compression? I had thought of just selling the bottom unit. Had hoped to get my money back from the guy who sold me the motor. Or as I said sell the lower unit, it seems good.
The motor ran great for a little while, until the plugs fouled.
Bummer
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: 150HP 1987 #1 Cylinder is Fouling the Plugs HELP

Wood, 70 PSI is not too good. It could have been zero. You can try spraying some Seafoam into the spark plug hole and turn it over by hand a couple of times. Now let it sit for a few hours and take another compression test. It may go up a bit. Ideally you want at least 90PSI. If this doesn't work, you can try to run it as is, or repair the one bad cylinder. I would run it, but that is just me. You do need to fix the issue (lean fuel or bad cooling) anyway,
 
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