Ahoy,
I have a 1990 90 HP (906X90A) on a 17ft spectrum, purchased new. Starts well, idles fine,
gets right on plane. After running at high speed for 10-15 minutes it seems like the engine just shuts down. Pull it back to neutral, starts right up and idles fine. Put it in gear and can
get to approx. half throttle, and the engine will stall again. If i keep it at something just short of the throttle death position, the engine will run smoothly, then pick up and go for another minute or two, then shut down again. The longest run of the day will be the first
off the dock. The greater the load, the shorter the initial run will be. The engine will idle and run low speed all day long.
What I've done: after stall, disconnect the line from the tank, idle for several minutes until the primer collapses and the engine runs out of gas. Primer stays hard otherwise. Re-prime the engine, starts right up, runs WOT for two minutes then stalls. The engine never really acts lean. In line fuel filter stays full. I'm leaning (NPI) away from fuel being the problem.
Checked the resistance of the triggers (on land) all 54 ohms no change when advancing or wiggling wires.
Checked stator resistances all approx 725 ohm.
Compression numbers: 1=115, 2=125, 3=120 with my old guage. don't know if it's relevant for an ob engine but wetting the cylinders made no measurable difference.
Is checking the pack voltages at speed the next step, or should I eliminate other simple things I haven't thought of yet ?
Thanks,
Tom
I have a 1990 90 HP (906X90A) on a 17ft spectrum, purchased new. Starts well, idles fine,
gets right on plane. After running at high speed for 10-15 minutes it seems like the engine just shuts down. Pull it back to neutral, starts right up and idles fine. Put it in gear and can
get to approx. half throttle, and the engine will stall again. If i keep it at something just short of the throttle death position, the engine will run smoothly, then pick up and go for another minute or two, then shut down again. The longest run of the day will be the first
off the dock. The greater the load, the shorter the initial run will be. The engine will idle and run low speed all day long.
What I've done: after stall, disconnect the line from the tank, idle for several minutes until the primer collapses and the engine runs out of gas. Primer stays hard otherwise. Re-prime the engine, starts right up, runs WOT for two minutes then stalls. The engine never really acts lean. In line fuel filter stays full. I'm leaning (NPI) away from fuel being the problem.
Checked the resistance of the triggers (on land) all 54 ohms no change when advancing or wiggling wires.
Checked stator resistances all approx 725 ohm.
Compression numbers: 1=115, 2=125, 3=120 with my old guage. don't know if it's relevant for an ob engine but wetting the cylinders made no measurable difference.
Is checking the pack voltages at speed the next step, or should I eliminate other simple things I haven't thought of yet ?
Thanks,
Tom
