'87 Johnson 30 hp. Here's the problem. When I first take off the engine runs great. After about 5 minutes it will power down and start cutting out. I'll back off on the throttle to around 1800 rpm and it will run fine. If I throttle up on it gently it will act like it is missing, if I open it up the motor revs to about 2000 rpm and dies back then revs again. Some times it will clear up for a time and run fine only to do it again after a few minuts. I'm not a boat motor guy, but it seems to me that it is starving for gas. Could it be my fuel pump is going bad?
2006-09-30 12:40:51 · 5 answers · asked by mad_mav70 6 in Cars & Transportation ➔ Boats & Boating
Well, these are all good suggestions and definitely possible. Without going to the lake with your motor I am just guessing, but you say it will run ok for about 5 minutes before the problem occurrs. So, I think your problem is electrical in nature. If I had to guess, I'd say the stator and/or trigger is going bad. The stator is beneath the flywheel. It is designed to advance the spark at higher rpms automatically. In other words the stator has what is called a "higb side" and a "low side". Guess where the crossover point is----------about 2000 rpm's. That is right at the point you are having the trouble. If the problem was carb or fuel related, it would be occurring from the git-go, not after 5 minutes. I think the problem is electrical in nature and my vote is for a bad stator. It would be interesting to know what you ultimately find out about your moter!
2006-10-03 20:49:58 · answer #1 · answered by price7204 3 · 0⤊ 0⤋
You most probably have a temperature sensor problem which will cut your RPM's automatically when the engine overheats. The powerpack will kick in and not allow you to run above 1800 to protect the engine but should allow you to get back home slowly. Check your water discharge which should be strong, if not suspect a bad impeller and replace. If you are on pre-mixed gas/oil that is not the problem.
2006-10-01 04:12:37 · answer #2 · answered by Mike D 3 · 0⤊ 0⤋
make sure the pump bulb on the gas line is working properly. When disconnected from the motor. it should stay hard. there is a tiny fuel pump on the side of the carb. while your are going down the lake try pumping the gas line bulb if the motor picks up and runs better, replace the fuel pump.
2006-09-30 16:41:37 · answer #3 · answered by redneck 3 · 0⤊ 0⤋
Possibly the vent on the fuel tank isn't open.
2006-10-03 11:17:16 · answer #4 · answered by Audio God™ 6 · 0⤊ 0⤋
I would try a carb overhaul. if it sat for a while the fuel passages will get gummed up.
2006-09-30 14:30:38 · answer #5 · answered by Anonymous · 0⤊ 0⤋