Motor: Johnson 150HP - 1988 - Model: J150STLCCA
The motor is very difficult to start. It takes several chokings. Once it starts, it does not run cleanly. It has episodes of surging during idle. Once we get going, it runs pretty flawlessly WOT for about 4 minutes.
After a few minutes, it starts to lose power - almost like someone pinched the fuel line, then let go. It will do that a few times then lose power, like we are at half throttle. If we keep it at WOT, it will periodically surge, but will never maintain full power.
To me, it seems like a fuel/air issue. We tried squeezing the bulb while running, and that had no impact. We also gave it a good SeaFoam treatment.
Our next step is to rebuild the carbs. I do not know a lot about these motors, but my concern is the fact that it runs fine for several minutes.
Any ideas? Thanks in advance.
The motor is very difficult to start. It takes several chokings. Once it starts, it does not run cleanly. It has episodes of surging during idle. Once we get going, it runs pretty flawlessly WOT for about 4 minutes.
After a few minutes, it starts to lose power - almost like someone pinched the fuel line, then let go. It will do that a few times then lose power, like we are at half throttle. If we keep it at WOT, it will periodically surge, but will never maintain full power.
To me, it seems like a fuel/air issue. We tried squeezing the bulb while running, and that had no impact. We also gave it a good SeaFoam treatment.
Our next step is to rebuild the carbs. I do not know a lot about these motors, but my concern is the fact that it runs fine for several minutes.
Any ideas? Thanks in advance.