2001 GTX DI Serious Loss of Power, MAINT light

[JDusza]

Hi. I usually work on outboards but I'm venturing into PWCs because we lost our marina and help is needed.
I'm chasing a ghost in a 2001 GTX DI, serial ZZN40402A101.
Interesting compression test with 125 psi in the front cylinder and 145 psi in the rear.
Randomly, at start-up, the unit will experience a serious loss of power and will display the MAINT light. It will smoke like crazy. If this were an outboard, I would say it's choked up. It will clear up if you stay with it trying to find a sweet spot in the throttle to keep it on the verge of acceleration. Might take 5-10 minutes.
Other times you can jump on it and have a great ride, straight away.
Fresh fuel, fresh oil, new battery, solid connections, new spark plugs.
Not sure if this is related, but when I first got the unit and opened the hull drain, quite a bit if raw oil drained out. Must have been a pint. So, there's been a spill or there's a leak somewhere unseen in the bilge. I think I'm going to have to pull the exhaust to find the oil leak.
I see several posts of DI power issues leading to the rectifier. What do you think? Will the rectifier fail in a flaky way or will it be a hard failure?
Thank you,
J

 

[WaarrEagle]

A compression delta of 20 psi between cylinders is not a good sign. Have you checked fuel pressure? Should be 27 psi with the key on and 107 while running. A code reader (CanDooPro) would tell you what code it is throwing. The service manuals are available on the internet with a Google search and are also really helpful.

 

[JDusza]

Thank you, WaarrEagle.
Yeah, the compression isn't great. I'm not sure what to make of that. Next time I'm at the machine I'll try a little oil in the cylinder and repeat to see if I get an indicator from the rings. I looked in the cylinders with a camera and do not see any damage. It doesn't look like it has any overheating damage. From what I can see, the walls look smooth and are not scarred. There is carbon build-up on the piston face. The plugs are a nice light toasty brown.
A said, I'm new to these. I looked up the specs to find this was sold as a 57 mph machine. Right now it runs an exhilarating 50. Can that be expected after 20 years? Doesn't seem too bad ... there's loss on the engine side and there's loss with the drive wearing, too, right?
Any idea when I should declare the compression a very serious problem?
Thank you,
J

 

[mikidymac]

I would agree, perfect compression is on a DI is about 135.

You don't "add oil" to a 2-stroke to check rings. If your tester is good and the compression is low you have a mechanical engine issue.

 

[JDusza]

Thank you.
Yup. Tester is good. Gonna have an issue...
J

 

[POPPS]

Pull out the rav of the 125...look at the piston,,,look for scoring for sure.

 

[XPLORx4]

Significant oil in the bilge may be present due to leaking seams on the 2-piece oil reservoir. Check the seams for seepage. Oil will usually leak out of the seams when the oil level is above the seam. Replace the tank to fix this issue.

 

[XPLORx4]

DI machines are notoriously sensitive to low voltage and will light the MAINT indicator along with a loud beep, and may enter limp mode. Check the voltage while the engine is running. Anything below 13 volts or above 14.6 indicates a bad rectifier.

I bought the CanDoo Pro tool to diagnose issues on both of my 02 DI's. Although the tool and software was expensive, it's been tremendously helpful in troubleshooting issues and has allowed my skis to spend less time "under the wrench" and more time on the water.

 

[JDusza]

Thank you for the info.
I will look for scoring.
I will also look at the oil reservoir. Funny you should say this because when I was wiping up the mess I noticed a lot of oil at the seam of the bottle and did question it. Surprising design error.
Appreciate the encouragement on the CanDoo as well. If it will provide useful direction for the amateur...
I really appreciate the inputs. Thank you,
J

 

[POPPS]

The oil tank will leak along the seam but against the gas tank,,,so you can't see it,,,sometimes they have crack on the bottom,,,there is a thread for a diy repair involving plastic weld repair,,,or,,,just fill the tank to below the leak if the leak is not the bottom of the tank,

 

[Nbracing68]

As far as the oil tank search Seadoo oil tank repair. It’s real simple and it works. I “rewelded” the seam on mine for less than $4 with a lighter and ice maker water line. Much cheaper than replacing the tank.

 

[XPLORx4]

I tried welding the seam on my tank with HDPE water line, but it didn't hold. It just cracked off and leaked again when I applied pressure against the seams (as if the tank were strapped back into place). I confirmed the failed seam by blowing into the filler neck while keeping other openings covered up. Considering how much of a pain it was to remove the tank, I did not want to repeat the labor any time soon, so I just bought a new one. On my 02 RX DI, the seams are also weeping slightly but not oozing oil. In order to R&R that tank, I'll need to pull the exhaust off, so I bought a pre-owned seamless tank on ebay so it'll never fail again. I'll probably replace it over the winter.

 

[_jkxu]

DI machines are notoriously sensitive to low voltage and will light the MAINT indicator along with a loud beep, and may enter limp mode. Check the voltage while the engine is running. Anything below 13 volts or above 14.6 indicates a bad rectifier.

I bought the CanDoo Pro tool to diagnose issues on both of my 02 DI's. Although the tool and software was expensive, it's been tremendously helpful in troubleshooting issues and has allowed my skis to spend less time "under the wrench" and more time on the water.

Hi how would i go by measuring the voltage simply getting a volt meter and hooking it up to the positive and negative off the battery whilst running ??

 

[mikidymac]

Hi how would i go by measuring the voltage simply getting a volt meter and hooking it up to the positive and negative off the battery whilst running ??

Yes.