1989 Merc Black Max 200hp

J

jmabrye5

Recruit
Joined
Mar 31, 2012
Messages
2
About 5 months ago I replace the head gasket in my motor, and the motoer never ran better. Last week it had some trouple getting on plane, but seemed to run okay once it got there. Today it really struggled and while running at top speed I started to hear a knock and lost some power. The engine will run, but the knock is dtill there and loud.
Any ideas what the problem may be?
 
jerryjerry05

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,927
Re: 1989 Merc Black Max 200hp

Why did you replace the gasket?Ther usually a reason for failure.
Sounds like there might be a problem with the new gasket.
No oil in the system?
Bad rod?
Pull the head again.
A bad thermostat on one side can make it overheat and go bad.
 
J

jmabrye5

Recruit
Joined
Mar 31, 2012
Messages
2
Re: 1989 Merc Black Max 200hp

The head gasket blew out in November, complete loss of compression in two cylinders. I assume it was the original and being an '89 I don't think it was that unusual. With the knock that is is present, I am guessing that pulling the heads isn't going to reveal the real problem this time. I am going to do a compression check this morning to see where the problem is. I will pull the heads again, and hope the gasket is the issue. I mix my oil, so that isn't the problem. I will post later today with results.

Thanks,
 
You must log in or register to reply here.
Top