115 Mercury outboard missing at WOT

[Popsbahr]

First post. I'm trying to help my father-in-law figure out a problem with a 1995 Mercury 115 hp outboard. He bought the engine used, he's having a problem with the engine missing and bogging down at WOT. The engine runs great out of the hole, but when the RPM's get above 3700 the engine starts missing.

Fuel pump has been replaced, new plugs, clean fuel and filter, oil pump serviced. Would appreciate any suggestions.

 

[Laddies]

Re: 115 Mercury outboard missing at WOT

If you tthink it could be a electrical miss disconnect the 2 yellow wires from the rectifier/regulator and test run a shorted one will heat the stator and cause a random high speed miss

 

[Popsbahr]

Re: 115 Mercury outboard missing at WOT

Thanks. I'll pass this on.

 

[belewsonmymind]

Re: 115 Mercury outboard missing at WOT

Could be the anti-siphon valve. The anti-siphon valve is where the fuel line connects to tank. Does the primer bulb collapse when the problem begins? If so, you may need to replace the valve. If not, check the fuel filter and fuel pump.