85 hp can't get normal high rpm's

[gueppebarre]

This motor went from 4800 rpm WOT to 3400 all of a sudden. Starts easily, idles ok. Checked fuel system all the way thru, pulled, cleaned, and reset carbs, fuel pump visually ok (pumping bulb at WOT doesn't help) - spark advance operating smoothly. Compression 120 - 122 - 120; coils all firing based on timing light check; plugs all look the same - light brown to black deposits (until I cleaned them).

THEN:
Checked ign parts - one side of stator (to CD #2) reads 705 ohms (within spec of 680-800), other side (to CD #1) reads 420 ohms. Triggers all read 47 ohms. Section of stator to rect reads <1 ohm.

There appears to be at least some problem with this stator, but can this cause a loss of high-end power? It doesn't run as smooth as before at 2000 rpm, so something's going on. Can it be firing and still not operate well?

Thanks - gueppe

 

[chuckz]

Re: 85 hp can't get normal high rpm's

Pull the prop and look for monofilament wrapped around the input shaft.

 

[newbie4life]

Re: 85 hp can't get normal high rpm's

I'm having a very similar issue with mine right now. For whatever reason, it won't jump out on a plane like it did earlier this year. It seems to be getting worse instead of better.

My mechanic b-i-l says "90% of all boating problems are fuel problems." It acts like it's not getting enough fuel at wot. Once, it even died on the way across the lake, but started up right away. I thought maybe it was a clogged vent?

I'm thinking about taking a piece of hose, sticking it into a can of fresh mixed gas, and connecting that to the fuel inlet, to eliminate the possibility of bad gas in the gas tank.

 

[steelespike]

Re: 85 hp can't get normal high rpm's

Pull the line off the pump output at the carbs put in a can and carefully crank; should be strong steady pulses.You could carefull squirt fuel mix into the carbs at speed check the reaction.