It is an STLCEM 1989 Johnson 150 GT
I bought a boat with this motor on it. The previous owner ran it hot. I took the motor completely apart. One piston melted a little but did not score the walls. I honed all of the cylinders, installed new rings, one new piston, new t-stats, new water diverters and rebuilt the carbs and a new water impeller.
The motor cranked fine. Good water flow out the tell tale. Everything seemed fine. Ran the motor easy once a week and never above 3000 rpms just taking it easy. Took it out the other day and after about 20 minutes I opened it up some. It got to around 3200 rpms and got an overheat alarm?? The first couple of times that I ran it was in smaller lakes and I never ran it more than about 10 minutes at a time until this last time in a bigger lake. I let the engine cool and ran it back to the landing at a slower pace and never got the alarm again.
Compression on the cylinders were all between 83 and 89 when I put it back together.
Any ideas what to look at first??
Thanks
I bought a boat with this motor on it. The previous owner ran it hot. I took the motor completely apart. One piston melted a little but did not score the walls. I honed all of the cylinders, installed new rings, one new piston, new t-stats, new water diverters and rebuilt the carbs and a new water impeller.
The motor cranked fine. Good water flow out the tell tale. Everything seemed fine. Ran the motor easy once a week and never above 3000 rpms just taking it easy. Took it out the other day and after about 20 minutes I opened it up some. It got to around 3200 rpms and got an overheat alarm?? The first couple of times that I ran it was in smaller lakes and I never ran it more than about 10 minutes at a time until this last time in a bigger lake. I let the engine cool and ran it back to the landing at a slower pace and never got the alarm again.
Compression on the cylinders were all between 83 and 89 when I put it back together.
Any ideas what to look at first??
Thanks