RPM's Jumping up

[Wally World]

I noticed when running the boat this weekend that a couple times the Starboard engine would jump up in RPMS, about 600 RPM's up and then back down. It would pick up speed as it increases.

Any ideas?

Yamaha 2011 F250's.

 

[noXcuse]

When is the last time you changed the fuel separator?

 

[Wally World]

only about 15 hours since all filters and separators have been changed.

 

[Tom-Lisa]

Wally

I had a similar issue shortly after the repower of my marlin. I found that the main ground wire on the engine had loosened up. I believe it was the port engine. I went thru and checked all the connections on both motors and no more issues. Might not hurt to take a quick look.

Tom

 

[outlaw027]

I think i would have my prop checked.

 

[Wally World]

Tom Lisa,

Thanks for pointing that out. My ground wire has separated. I am hoping to check it out this weekend. Would have never thought.

Thank you

 

[Wally World]

Ok, Any other suggestions? The ground wire is actually fine. Anyone else have this problem in the past with their Yamaha's?

 

[JeffN]

As noted above check the prop. The hub may be spinning. Do you have fouling on the prop?

 

[Wally World]

Don't think it is a fouling prop since it seems to push the boat as well and the boat will turn to Port as the starboard engine jumps up in RPMS.

 

[JeffN]

Yeah that does not sound like a prop then.