I bought a 1999 Sea Doo GTX RFI 8 months ago. I suspect the previous owner ran the wrong 2 stroke oil in it. My plugs and RAVE valves continue to foul out after a couple of hours of usage. I had drained the old oil out and put a new filter in. I'm not sure what my next step should be. It runs great for 2-3 hours and then dies at idle as the plugs get fouled. Any help would be appreciated.
1999 Sea Doo GTX RFI fouling plugs
- Thread starter cparrish
- Start date
Any idea on how to adjust the oil injection?
One of the pics is upside down. Compression was 155 on both pistons.
Looks like the first pic is also mirrored, I read too little oil from it.
The second is so close I wouldn’t think it was an issue, just some idle adjustment and its on either side.
There is a temp sensor in the intake, disconnected or failed it may fool the injection to see wayyy cold, enriching the mixture. The right way to test it is checking the wire colors at the plug(2 wire connector in the intake, it is way down towards the starter almost upside down), then locate these wires in the big plug on the MPEM, lower left plug if you face the front of the MPEM, unplug and check resistance. Search for “sea doo temp sensor ohm chart” to see what it should read at the temp you are at.
These guys rarely fail but it happens, more likely there is a loom/connector issue. That’s why checking at the plug can confirm/eliminate all that in one test.
Another possibility is the other 2 guys: Throttle Position Sensor and air intake pressure sensor. I’ve had the latter one fail but the symptoms were different, still I guess it could fail causing rich condition just as well.
A failed TPS…mayyybe. That guy needs to be calibrated too, I really don’t have experience with what symptoms are seen there aside from generally running like sh!t.
I’m currently chasing issues with 2 of these machines, more of a lean issue on one of them and what looks like an ignition issue in the other, but it could be fuel.
I’ll keep on reporting in another thread I have on RFI Lean issue as I find out more. It may help even if symptoms are different.
The second is so close I wouldn’t think it was an issue, just some idle adjustment and its on either side.
There is a temp sensor in the intake, disconnected or failed it may fool the injection to see wayyy cold, enriching the mixture. The right way to test it is checking the wire colors at the plug(2 wire connector in the intake, it is way down towards the starter almost upside down), then locate these wires in the big plug on the MPEM, lower left plug if you face the front of the MPEM, unplug and check resistance. Search for “sea doo temp sensor ohm chart” to see what it should read at the temp you are at.
These guys rarely fail but it happens, more likely there is a loom/connector issue. That’s why checking at the plug can confirm/eliminate all that in one test.
Another possibility is the other 2 guys: Throttle Position Sensor and air intake pressure sensor. I’ve had the latter one fail but the symptoms were different, still I guess it could fail causing rich condition just as well.
A failed TPS…mayyybe. That guy needs to be calibrated too, I really don’t have experience with what symptoms are seen there aside from generally running like sh!t.
I’m currently chasing issues with 2 of these machines, more of a lean issue on one of them and what looks like an ignition issue in the other, but it could be fuel.
I’ll keep on reporting in another thread I have on RFI Lean issue as I find out more. It may help even if symptoms are different.
Thanks for the info. I plan on taking a look at the seals this fall. I have been carrying extra plugs. I can usually get 3-4 hours use out of them before cleaning them or replacing them.
I’ve had a bad spray pattern foul plugs on an sdi snowmobile before, actually caused low compression in that cylinder. Rebuilt the top end same problem, had the injection tors professionally ultra sonic cleaned and problem solved in my situation. I was fouling plugs before the cleaning
Yes, good thing you found that.
I’m not sure how many times you can clean plugs, I have rarely ever fouled a plug but if I’m remembering correctly you could possibly take a foiled plug and let it sit for a few days and it may work again. I’m not sure about what I’m saying but I think I read that the porcelain soaks in fuel and if you let them thoroughly dry they could be re usable.
I'm glad you're posting again man. I like reading your stuff. You keep things in perspective.
I might pick up a load tester but before I do, what I have been doing is just putting a volt meter on while cranking, if the battery goes below 10 volts while cranking I figure it’s done if I have recently charged it. Not sure how low the volts should go while cranking? I just used the number 10. The only time I have done this the battery actually went to 7 or so while cranking so I’m sure that one is done. Is there any benefit to a load tester over this method
Them skis are SNEAKY.
Update on new oil injection cable.
Took out ski after cable installed and it went into limp mode after about 15 minutes of riding. Got it to the dock and it died and would not start. This has happened twice now. Oil injection lines are lined up. I don't understand what's going on with it now. Could it be a bad battery. It's 18 months old.
Took out ski after cable installed and it went into limp mode after about 15 minutes of riding. Got it to the dock and it died and would not start. This has happened twice now. Oil injection lines are lined up. I don't understand what's going on with it now. Could it be a bad battery. It's 18 months old.
I know you took a compression test before but have you taken one lately just to be sure where you stand. You have some great advice above from @Gritzlor and others. Have you tried everything mentioned above? Stock air box? Originally the one plug was definitely rich, did you end up having the injectors inspected and cleaned professionally? As I mentioned I’ve had good luck with having them cleaned. Did you have fresh plugs in after the new oil cable? How do they look now?
