@help One engine surging at steady throttle

[AZMark]

[USERGROUP=9]@HELP[/USERGROUP]

Just got on the water and one engine is surging between 5-6000rpm when just cruising. Other engine is fine.

Any ideas? Thanks

 

[zipper]

Seconding [USERGROUP=9]@HELP[/USERGROUP] Loose spark plug coil boot? Bad plug?

 

[GTBRMC]

Agreed - start by eliminating any possible spark plug issues.

 

[AZMark]

Seconding [USERGROUP=9]@HELP[/USERGROUP] Loose spark plug coil boot? Bad plug?

The coils are all tight. It’s weird, I slowed down to about 5100 on each engine & it’s stable there, but if I go to 6000 then the one keeps falling back to 5000 and then surging up again like it’s starving for fuel or something.

 

[Bruce]

Check for anything stuck in the jet pump. It may be cavitating.

 

[AZMark]

Agreed - start by eliminating any possible spark plug issues.

I don’t have a socket on the boat to check the plugs themselves.

 

[AZMark]

Check for anything stuck in the jet pump. It may be cavitating.

I don’t feel anything from the clean out port side.
Oh well at least it’s still running generally ok. I’ll probably figure it out at home.
Thank you all for the quick replies!!!

 

[GTBRMC]

Good luck!

 

[Dixie Highway]

I’d check air filter too. If it’s partially obstructed or wet it can potentially cause a similar issue.

 

[Ajax]

Spark plugs

 

[AZMark]

Spark plugs

Definitely time. I didn’t even know where they were until I pulled the cover to check the coils. I’ve done no engine maintenance on this boat yet, just minor mods

 

[Bruce]

@AZMark, have you changed the oil?

 

[AZMark]

@AZMark, have you changed the oil?

It was done at the 10hr right before I bought it. I just check it periodically and it looks super clean. Boat only has 39 hours on it.

 

[Ajax]

Definitely time. I didn’t even know where they were until I pulled the cover to check the coils. I’ve done no engine maintenance on this boat yet, just minor mods

i had very similar issue at beginning of this season. Starboard motor jumping all around. Changed plugs. Problem gone.

 

[Seadeals]

Spark plugs and oil change every season is great preventative maintenance regardless of hours. New plugs are the best and easiest start to solving your problem.

 

[djetok]

It was done at the 10hr right before I bought it. I just check it periodically and it looks super clean. Boat only has 39 hours on it.

Do you have any add ons? like a speed control

 

[sunbyrned]

Sounds like something in the impellers. Happened to me today. Sucked up something but couldn’t feel it from the clean out port. Going to have to pull the pumps tomorrow.

 

[Seadeals]

I appreciate those who don’t mind pulling pumps; but be sure to thoroughly inspect from the intake, plug port/tube and pump outlet first as the fix can often be so easy. It is common to get a tiny piece of leaf, twig or even piece of pine needle stuck floating in the impeller area that causes cavitation. You will hear the buzz. It does not have to be wrapped around the shaft or impaled on an impeller blade to cause cavitation and it may be small and elusive enough (even floating in the tube after you pull the cleanout plug). Without the sound of cavitation, which changes pitch with rpm, spark plugs are the #1 culprit of unexpected engine rpm changes (excluding the kill switch of course).

 

[Sneedman]

[USERGROUP=9]@HELP[/USERGROUP]

Just got on the water and one engine is surging between 5-6000rpm when just cruising. Other engine is fine.

Any ideas? Thanks

i am having a smilliar issue on my Ar195s single svho. What fixed your issue? 73 hrs etc. have already changed plugs.

 

[AZMark]

i am having a smilliar issue on my Ar195s single svho. What fixed your issue? 73 hrs etc. have already changed plugs.

I think it was probably some debris in my impeller because it went away pretty quick. I changed plugs right after too.