Stall @ 1800K under load

[asm_]

Hi,

I have search high and low and can't seems to find the answer I'm search.

I recently acquired a 1982 Mercury 115. Both in water and on ear muff, it starts easy, idle forever in our out of gear. But, when I try to throttle up under load, the motor stall at 1800K. The cut out RPM is so precision and repeatable that it almost act like a motor RPM governor. While I was running a kinds of test on the electric portion of the motor, I noticed at idle, the lower carb is not suck as much air as the upper two carbs. This become quite evident when I throttle up to about 1500RPM on ear muff. The lower carb is definitely not pulling its weight. Checked spark on the lower cylinders and it the spark just fine.

If any one have any suggestion or idea that may point me to the right directly, please do share.

Thanks

B

 

[Maxz695]

Re: Stall @ 1800K under load

Check the compression in the affected cylyinder. This may be a sign of a bad stator. Do the appropiate test for yours in a repair manuel for your engine. If thats good then maybe the rev limiter might have something to do with it. Bad suction on the lower carb is indicating bad compression.

 

[Chris1956]

Re: Stall @ 1800K under load

If it cuts out precisely at the same RPM, it is likely a stator. Did you try hitting the choke for an instant as you approach 1800RPM? If that fixes it, there may be trouble in the carbs mid-range fuel circuits. This would be unusual...

 

[asm_]

Re: Stall @ 1800K under load

I should mention, Compression checked out OK, don't remember what the number was, but it was fairly equal all across the board.

As for stator, I completed the testing procedure from CDI and determined the stator's output was a bit off. Therefore, a new stator was installed. The motor still stall at 1800RPM after the new stator.

Any other idea?

B