How do my plugs look?

[k_dog345]

Rear cylinder





Front cylinder





Carbs recently rebuilt and set to stock settings. Spark plugs pictured have about 2-3hrs on them

SYMPTOMS
- runs fine with fresh set of plugs riding solo at first. Good power and throttle response.
- after a few minutes of running, throttle is not as responsive especially under load. Ski starts to have a hard time getting up on plane. Also it becomes very hard to start (needs throttle) and normally takes several attempts. Once it stays running I have to feather the throttle
To clear it out before it hits powerband again. This is exaggerated especially if I take a passenger or put the ski under heavy load.

Thanks in advance!

 

[POPPS]

Plugs look great,,,

 

[edchris]

Plugs look fine. Sounds like a fuel delivery issue.
since it runs fine to begin, then, bogs down, I’m thinking not enough fuel, possibly venting issue.
I had your symptoms on my ‘95 SPI, feathering the throttle to get it going, then ran fine as long as I stayed at higher power.
Took the carb to a dealer for cleaning/rebuild, has run fine ever since.

 

[POPPS]

plugs should look like a nice draught ale,,,and the ring,,,should have a tinge of light brown,,,like yours,,,

 

[k_dog345]

Thanks @POPPS!

Just an update. I notice when I’m idling the skis rpms seem to fluctuate. It’ll act like it’s running a way then bog down a bit and speed up again. Sometimes the bog gets so bad it kills the ski and I have to restart and the behavior continues. Plugs look good, but do you think that my carbs might need tuning? Or does it sound like a separate issue?

 

[mikidymac]

Have you rebuilt the carbs with new Genuine Mikuni parts? The engine should not surge and die.

 

[POPPS]

Sounds like partial blockages in the carbs,,,

 

[tomski]

Definitely a fuel delivery issue...had the sameish issue with one of the XPs on Lake Nokomis. Remove and tested fuel selector and worked fine. For me, I will need to clean/rebuild carbs. I know you had them done but it's possible they got something in them again.