rpm variation in port engine

[carver]

my 5.7l mercruiser engine varies sometimes up to 300 rpm with no change in speed it does stay in long at one range. this does not happen all the time both engines and still have problem mechanic is miffed. coud it be a prop isssue ist is not cavitation

would appreciate some elp thanks

 

[ScottRogers]

Re: rpm variation in port engine

300 RPM is nothing to be concerned about, how is the tension on the throttle? Or more than likely your gauge is off just a bit

 

[carver]

Re: rpm variation in port engine

thanks for your response. I can feel the engine rpm increase without any incresae in speed so I doubt it is the gage. Could it be something with the prop