Mid trottle surging?

[brownhunter]

I have a 04 Mercury 25hp bigfoot. I noticed today the motor would suge up and down in RPMs while in mid trottle, but at trolling speed it was fine and same with full trottle was fine.

Why does this happen???

Also occasionaly the motor makes a kinda high pitch squeal sound. kinda like a belt in a car? It will last a minute or two then go away and then come back at random times while trolling.

anyone got ideas on these things?

 

[brownhunter]

Re: Mid trottle surging?

bump

 

[aussieflash]

Re: Mid trottle surging?

Surging is more than likely fuel related.Dirty carbs,jets,stuck needle/float in carb,filters........check it all but id start with a carb service and replace ALL gaskets with new.Dont forget to check all fuel lines are snug and not damaged.

 

[brownhunter]

Re: Mid trottle surging?

I'll look at it and try some carb cleaner. the motor has less then 100hrs on it. what about the squealing sound?

 

[brownhunter]

Re: Mid trottle surging?

bump