Wrong prop?

[walleyvoyager]

Has anyone ever heard of a prop being to big for a motor and making the motor misfire?

[upnorth]

I haven't. But I would start by checking your plugs.

[JohnMickish]

I imagine it could happen if the prop where pitched WAY to big and wouldn't let the motor get any kind of revs. If the motor where healthy to begine with the prop would have to be way out of the ballpark to fuel foul the plugs.

[DRH1175]

No. Unless you were running like a 15" instead of a 10". If your pitch is too high it will run at low RPMs when at WOT. When is it mis firing, what boat, motor and prop do you have? I would say bad fuel, or fouled plugs is more of the problem.

[walleyvoyager]

I purchased the boat this past winter. The motor ran when I bought it, with no issues. when i got it out for the first time this year it had an un consistent misfire. out of the hole sometimes or at the top end. I have 20 gallons of fresh gas in the tank, and Im running a new mercury kicker off the same gas. The kicker has no issues with it.

I dropped the boat off at a dealer to see what was up. After checking the plugs and hooking it up to the computer they took it for a wet test, they ordered a new prop. The current SS viper prop is to big for the 75 Evinrude? I'm not sure the size of the current prop but I've never heard of a prop making a motor misfire?

I figured new plugs or maybe an injector.

I was curious if anyone had run into this issue before?

[boatfixer]

If its too small, the rev limiter will make the engine miss. Over propped? It will be doggy but an actual miss fire?

[walleyvoyager]

It sounds odd to me also. That's what the dealer says. I guess I'll wait and see this week, when it should be done.

I just wanted to see if anyone else had even heard of this.