Motor stall beyond 3000 rpm-cuts out

BuilderFL

BuilderFL

Junior Member
1989 Mercury Black Max 200 HP
I would take the boat out and I could get on plane with no problems, but after a while, the motor would bog out, and loose power, it would run about 9 mph and turn 2500 rpm. There will be times that after 5-10 minutes later, the motor will kick in and start running great. Then it would loose power again and if I push beyond 3000 rpm, it would stall and just cuts out, however it's fine if I run at lower rpm.
Any suggestions as to the problem?
Thanks! :sad:
 
I just ordered a DVA adpter (ESP640) this morning thinking I was going to need it. I'll check the switch boxes today.
Thanks guys! :beer:
 
Yes its closer to 13.6vdc and its coming from my furuno fish finder. On the voltmeter it's harder to tell, but its over the 12 volts
 
phatdaddy, now that you mention the tachometer, I have been getting readings high in the 7k rpms at full throttle and was concerned. But then I connected an external tachometer and the readings were within normal parameters. Just thought I had a bad tachometer. Your think it may be tied to the stator?
 
Well got my DVA delivered (tooldiscounter.com) and all tests came in within the CDI parameters. However, I noticed that my lower carburetor was leaking lots of fuel...a stuck float that was cleaned and fixed. Also noticed that there was a water leak coming from behind the middle coils; a hole in the exhaust manifold cover. Took that out, will probably repair from the inside with JB Weld and when I get the gaskets and install them, will test it and keep you informed.
Do you think any of these problems could have cause the original symptoms as reported or just other stuff that needed attention?
 
what did the high speed switch box outputs look like. Remember to disconnect the bias wire between the switch boxes when testing out puts(white/black wire) make sure the grounds on all the coils are nice and clean.
 
Spare, it will be about two weeks before I can get to them. Will be working in San Francisco and then Albuquerque, but I did not remove the bias wire between the switch boxes. Maybe the reason for both to have similar readings.
 
spare, disconnected the bias wire between the switch boxes (BTW this is a 16 amp flywheel) and these are the max readings to ground with the DVA:
blue=269v
blue/white=284v
red=198v
red/white=177v
What do you think?
 
builder, i might have one of the older stators. it was a spare i had for my 84 150, but my "new" 94 has the 40 amp. its yours if you need it & i can find it. let me know.
 
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