97 GTX keeps fouling plugs. Please help!!!

[Bsarno]

I could use your help.
I have a 1997 Seadoo GTX. It has dual carbs. I put brand new Mikuni (sp?) carbs on it. I replaced all the fuel lines. Redid the rave valves. I don’t know all the technical language but you get the idea.
Here’s my problem… When I put brand new spark plugs in it runs fantastic. Then after about 25-45 min it starts to run worse. More and more smoke coming out of the exhaust. The engine doesn’t run as well.
It seems overall like I keep fouling plugs or it’s running too rich. I checked the oil pump markings and they lined up perfectly. So the oil pumIt seems overall like I keep fouling plugs or it’s running too rich. I checked the oil pump markings and they lined up perfectly. I don’t know what else it could be. Can you please help me with any ideas?

 

[mikidymac]

Did you verify the new carbs have the correct springs, seats, jets and settings?
Is the oil pump adjusted correctly?

 

[Bsarno]

Did you verify the new carbs have the correct springs, seats, jets and settings?
Is the oil pump adjusted correctly?

Thank you for those questions and your help. I did not verify anything on the new carbs because when I talk to the company that sold it to me he said that you can literally take it right out of the box and put it in and everything is set. I did check the oil pump adjustment and indicator looks like the two lines are perfectly lined up.
Do you think it could still be something in the carbs? What else would you suggest that I do?

 

[mikidymac]

I would verify the jets and all other settings.

 

[Jeremy72]

I ran into the same problem many years ago. I just kept replacing the plugs and it ran fine. Good luck

 

[Seadoo timebomb]

Is the smoke black, blue or white? Could you be sucking oil from rotary valve shaft cavity? You didnt mention any history on the motor. Taking water in to cylinder? Spark plugs, dry black, wet black, wet oily black or white?

If oil fouling open the plug gap up another 0.005".

 

[dr00andrew]

test your compression with a loaner tool from autozone. should be around 150 +/_ 5 psi.

these are what your carb settings should be around depending on engine condition

Needle/Seat Size: 1.5
Spring: Black 80 gram
Pop-off pressure: 39 psi
Pilot Jet: 72.5
Low Speed Adjuster 1 3/4 turns out
Main Jet: 142.5
High Speed Screw: 1/8 turn out

the stock pilot is 70 and the stock low speed screw is 1 turn out. try these out first. i am also assuming you have replaced the fuel lines as well

 

[Seadoo timebomb]

IF the ski runs fantastic for 30 minutes...That pretty much eliminates the carbs are a problem. If plugs are fouling, then confirm if from oil or fuel. It shouldnt be from fuel since replacing the plugs it runs fantastic again. Look at the plugs. What do you see? Describe the smoke coming out the back.

 

[Bsarno]

IF the ski runs fantastic for 30 minutes...That pretty much eliminates the carbs are a problem. If plugs are fouling, then confirm if from oil or fuel. It shouldnt be from fuel since replacing the plugs it runs fantastic again. Look at the plugs. What do you see? Describe the smoke coming out the back.

Thank you everyone. It sounds like all of these are good troubleshooting ideas. I’ll need to look at the plugs closer to describe them to you. Usually dark. We were out on the Sea-Doo today. It’s like clockwork. New plugs, runs awesome for a little while and then it starts to run worse. I do think that the gentleman who talked about making sure the new carburetors are adjusted correctly sounds wise. Again, since I’ve already checked the oil pump adjustment And it’s lined up perfectly.

 

[Bsarno]

test your compression with a loaner tool from autozone. should be around 150 +/_ 5 psi.

these are what your carb settings should be around depending on engine condition

Needle/Seat Size: 1.5
Spring: Black 80 gram
Pop-off pressure: 39 psi
Pilot Jet: 72.5
Low Speed Adjuster 1 3/4 turns out
Main Jet: 142.5
High Speed Screw: 1/8 turn out

the stock pilot is 70 and the stock low speed screw is 1 turn out. try these out first. i am also assuming you have replaced the fuel lines as well

This all sounds really good. The problem is I don’t know how to check all these things. So I’m probably gonna have to take them to my Seadoo mechanic. Does anyone know of a good seadoo mechanic anywhere near Gig Harbor Washington.

 

[dr00andrew]

This all sounds really good. The problem is I don’t know how to check all these things. So I’m probably gonna have to take them to my Seadoo mechanic. Does anyone know of a good seadoo mechanic anywhere near Gig Harbor Washington.

You will have to look hard and find a private guy willing to work on a 2 stroke seadoo. Most mechanics wont even want to touch them.

just remove your carburetors and check out the sizes of your seat and jets. They are all stamped in there and you will know what you havein there. There is a sticky on this forum telling you how to take apart the carburetor