Hey guys. I am having a problem finding out why my 2009 seadoo rxpx 255 runs lean. Has perfect compression. Never bogs down, or idles rough. And ideas

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Nick Wassenaar

New Member
Hey guys.

I am having an issue find a reason why my seadoo is running lean.
It's never hard too start, never idles rough, and runs perfectly.
Spark plugs are just white. Engine feels hot. Temp sensor never goes off on dash. I replace a coolant temp sensor. But that hasn't seemed too fix it.

Wondering if you guys could help me out a little
 
My spark plugs are a whitish Grey. And the engine feels hot. But my over heat alarm doesn't beep at me.

I just don't understand how it runs perfect but the plugs are turning white. Coolant never goes down or boils over. Hoping to find out what it is before a small problem can become a big problem.
 
I think many are thinking that you may not have a problem… but it is true that the plugs are often a brown color. But I don’t know that you need to be overly concerned with all other indicators being OK. Is the white plugs something that is changed from previous brown colored plugs or is this ski new to you and you are just concerned?
 
This jet ski is new too me. My old one had just had the nice golden brown color too the plugs indicating that it's running perfect. I like too try fix problems before they become big problems is all. Cuz excessive heat can damage gaskets and potentially melt an electrode on a plug. Which can lead to heavy damage on the piston.. or I could totally be overthinking it.
 
Do you have a photo of the plugs? Are you in fresh or salt water? If you are in fresh, the intercooler leaking can cause white substance on the plugs.
 
Maybe some miss understanding in post #7
Ignore rest if not true.

Water in intake system (intercooler leaks) likely will not show up as water accumulation in hull.

Water entering the intake and combustion can clean the power cylinder (including spark plugs). Adding water to the intake charge was used in the past to offset detonation.
 
It would help if you post clear pictures clearly showing the electrode and insulator so all can see your spark plugs

Do you have the correct heat range?
 
If it's making the full power RPM that it's supposed to, it's very unlikely that it's running lean since you'd have a power loss. I don't know what the expected full throttle RPM of that ski is, but you should be able to find it. Unless your previous ski had the same motor, you can't expect the plugs from this one to look the same.

The felt temperature of the engine's surface is useless as an indicator of it running lean, and since there's no overheat warning it's probably not overheating.

Post a photo of your plugs and state how many hours are on them, along with a description of how hard you run the ski. This info will help people help you.
 
How many hours or minutes on the plug....maybe they were changed by previous as maintenance And don't have enough time on
them to read an accurate color yet...?
 
I have never had a 4 tec run coffee brown plugs.some of the additives in fuel turns plugs a ashy color.if no alarms are coming on no codes and it runs clean and rpms are running correct.run it stop looking for problems that are not there
 
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