Water fouled plug, what causes this?

[Thetolleyman]

Customer brought me a 2001 Sportser LE, single engine 947 Carb'd

It won't rev much over 4300 rpm according to OE tachometer.

Seems like its missing a bit all rpms.

I put in new plug properly gapped and go for a run, this is what I get after 10 minutes. One plug wet and black, other one, what I think is called "water fouled". Its got a milky tan fluid on it like water mixed with oil. Below is a pic of the water fouled plug as soon as I pulled it out, and another after I wiped it off just to give you an idea of what was on there.


I repeated this test, just to confirm, and got the same results. I removed the carbs, went thru, reinstalled, ran test again, same thing. Any ideas?

 

[Dr Honda]

951 engine......... Probably a bad head gasket. it's the only seadoo 2-stroke with a conventional head gasket.

 

[Thetolleyman]

Is that common? Its a metal gasket, think I can put some "gasket maker" on both sides and re-install? At least just to test that theory? I'd hate to order one, wait 3-4 days to get it, then have that not be it.

 

[Dr Honda]

Nope... it won't re-seal, once the copper has been crushed.

BUT... if you pull the head... you will see the burnt spot if it's the problem. There really isn't any other place for the water to come in when it's running. If you had an exhaust leak... it would blow out any water while running.


Have you checked the compression?

When the carbs were off did you check the reeds?

 

[Thetolleyman]

Didn't check the reeds. I did find something on another forum about the exhaust manifold leak being pretty common and since its right above the carbs, the water gets sucked in, despite the air breather. Called it Water Ingestion, supposedly common 951 killer. I'll check for a manifold leak tomorrow, then pull the head if need be. I suppose if its a head gasket one side should be steam cleaned most likely.


Compression was 145 and 130, further apart than I'd like to see, but not low.