can changing prop cause engine to run rough?

[dlaxdal]

would changing a prop cause a 115 1993 2+2 run rough at higher rpm's

 

[JB]

Re: can changing prop cause engine to run rough?

Probably not.

 

[j_martin]

Re: can changing prop cause engine to run rough?

It is possible for exhaust restriction in the hub of some props to change engine tune enough to drive the mechanic near crazy.

I've seen it happen. It's rare, but it happens. Usually it's a cheap aluminum aftermarket prop that causes the problem.

I'm with JB, though, with the probably not.

It would help to have more information. Original prop model and pitch, new prop model and pitch. WOT rpm's before and after, etc.

The wrong prop can cause some serious troubles in an engine. Overloading an engine, for instance, can overstress everything. If the ignition is weak, it could cause it to misfire.

hope it helps
John

 

[dlaxdal]

Re: can changing prop cause engine to run rough?

I am not with the boat but they are telling me it runs ok until it get to full throttle

 

[CharlieB]

Re: can changing prop cause engine to run rough?

Increasing load with increasing RPM will show a faulty spark plug or weak ignition.

What plugs are in it, how much gap, and how old are they?

Change if at all suspect.

Use an inductive timing light at RPM, if the light goes OUT then you may have a weak ignition system that would need further testing to determine the cause.

 

[dlaxdal]

Re: can changing prop cause engine to run rough?

The plugs have the flat bottoms and they are two years old.
Where can you get timing light, harbour freight tools

 

[dlaxdal]

Re: can changing prop cause engine to run rough?

Do you think the bottom two plugs would go before the top??????