Tweet
having some problems with my 87 johnson 110hp. bought it this spring, ran perfect for about 20 hours, then something happened.
was cruising along, and then gave it full throttle. after about 30 seconds it suddenly just died and wouldnt start. cooled down and it started again, running rough. noticed the head gasket was leaking above #1 cylinder.
Brought it back home and got out the wrenches, pulled the head off and found the piston was melted! Pulled the powerhead off and stripped it all down on the bench, honed the 4 cylinders, new rings, new spark plugs, replaced the 1 melted piston, went over all the wiring since it was apart cleaned connections.
I figured this tragedy happened because of the leaking head gasket at cyl 1. As a precaution I looked into the carbs, the bowls were clean, i blew out the passages, everything seemed to be fine. Finished my rebuild, got it all back together, started up instantly in the driveway so I took it to the lake....
Ran okay a bit rough, as would be expected as the rings need to re-seat. Cruised around the bay for about 10 minutes varying rpm, no full throttle runs or anything just taking it easy. Gave it some more and then, YOu guessed it the same thing happened and now im back at home with what was a new piston MELTED just like the last.
Help a guy out here, what could I have possibly overlooked? I have built many diesel truck and 2 stroke bike engines, never had an engine fail like this before. Needless to say im frustrated, but I am not going to give up!
Sounds like the carb was running very lean and it roasted my piston twice? any other ideas? this happened in such a short time. I am experienced at building engines, honing, measuring ring gaps etc everything was assembled properly.
Thanks in advance, hope you enjoyed my frustrating somewhat embarrasing stupid story!
was cruising along, and then gave it full throttle. after about 30 seconds it suddenly just died and wouldnt start. cooled down and it started again, running rough. noticed the head gasket was leaking above #1 cylinder.
Brought it back home and got out the wrenches, pulled the head off and found the piston was melted! Pulled the powerhead off and stripped it all down on the bench, honed the 4 cylinders, new rings, new spark plugs, replaced the 1 melted piston, went over all the wiring since it was apart cleaned connections.
I figured this tragedy happened because of the leaking head gasket at cyl 1. As a precaution I looked into the carbs, the bowls were clean, i blew out the passages, everything seemed to be fine. Finished my rebuild, got it all back together, started up instantly in the driveway so I took it to the lake....
Ran okay a bit rough, as would be expected as the rings need to re-seat. Cruised around the bay for about 10 minutes varying rpm, no full throttle runs or anything just taking it easy. Gave it some more and then, YOu guessed it the same thing happened and now im back at home with what was a new piston MELTED just like the last.
Help a guy out here, what could I have possibly overlooked? I have built many diesel truck and 2 stroke bike engines, never had an engine fail like this before. Needless to say im frustrated, but I am not going to give up!
Sounds like the carb was running very lean and it roasted my piston twice? any other ideas? this happened in such a short time. I am experienced at building engines, honing, measuring ring gaps etc everything was assembled properly.
Thanks in advance, hope you enjoyed my frustrating somewhat embarrasing stupid story!
Comment