2001 SeaDoo GTX Di - Front Cylinder Has Low Compression and Fouls Spark Plug

[SeaDooGTXdi513]

Hi,
I have a 2001 SeaDoo GTX Di with 160 hours. With fresh spark plugs it runs good, but after about 5 hours I have no top end power. The front spark plug is completely fouled ( burnt looking ). The rear spark plug looks like it should.
I tested compression and have low compression in the front cylinder ( 90 psi). The rear cylinder has 120 psi.
Any advice on what to check next? Thanks !

 

[tkarvelis]

Your compression is too low. 120 is the minimum for a DI. The other issue being you are more than 10% between cylinders. You are due for a top end, and should think about a rebuilt crank. 200 hours is about all you will get, and since it is being rebuilt, it makes sense.

 

[tkarvelis]

Another possibility, but unlikely due to the compression numbers is a clogged fuel injector. A dirty injector will drip fuel instead of spraying it, and causing incomplete combustion.

 

[Coastiejoe]

How many hours are on the crank?

 

[SeaDooGTXdi513]

[MENTION=43374]Coastiejoe[/MENTION] - 160 hrs, I bought the PWC used and I don't think the previous owner replaced the crank.
[MENTION=76159]tkarvelis[/MENTION] - Thanks for the advice ! Do you think it would be worth paying the dealership to do a CanDooPro scan? Just wondering if the scan would turn up anything else?

 

[Coastiejoe]

At 160 your crank should be good. Top end and go from there.

 

[jhjesse]

Got a feeling you fix the compression problem that spark plug will start looking a lot better.
Unburnt the fuel with oil injection tend to foul plugs.

 

[SeaDooGTXdi513]

Thanks for the advice everyone !