97 gti Problems

[Pnut80]

Ok guys,

Took the Ski out last weekend for a run, Just replaced The PTO,Drive Shaft, and and Carbon Ring, Also at end of Last Season done the following: New Black Fuel lines, New Carb, Drained and replaced Gas. now onto this weekend. kids ride it for about 30 mins, then call saying it wont run, So they bring bring it back to dock, then i get on it and it runs fine, So next day we are riding it and after about 45 mins it starts running rough again. it will barely idle and when going full throttle the ski wont move but maybe 5MPH, seems like its starving for fuel or too much oil, Pulled plugs and they were really oily. What could be the issue to start looking at?

 

[LikeabossTM]

Ok guys,

Took the Ski out last weekend for a run, Just replaced The PTO,Drive Shaft, and and Carbon Ring, Also at end of Last Season done the following: New Black Fuel lines, New Carb, Drained and replaced Gas. now onto this weekend. kids ride it for about 30 mins, then call saying it wont run, So they bring bring it back to dock, then i get on it and it runs fine, So next day we are riding it and after about 45 mins it starts running rough again. it will barely idle and when going full throttle the ski wont move but maybe 5MPH, seems like its starving for fuel or too much oil, Pulled plugs and they were really oily. What could be the issue to start looking at?

Does this ski have a fuel tank breather vent? If so, maybe it's plugged. You should be able to blow into the tank through it. You could also try cracking the fuel fill cap when it starts to run rough to confirm (if it's a plugged breather vent then cracking the cap will accomplish the same thing, relieving the vacuum in the tank.

 

[Pnut80]

Does this ski have a fuel tank breather vent? If so, maybe it's plugged. You should be able to blow into the tank through it. You could also try cracking the fuel fill cap when it starts to run rough to confirm (if it's a plugged breather vent then cracking the cap will accomplish the same thing, relieving the vacuum in the tank.

I will look to see if it has a vent on fuel tank, and if not i will try the cap idea to see. Thanks

 

[GGuillot]

seems like its starving for fuel or too much oil, Pulled plugs and they were really oily. What could be the issue to start looking at?

Check the oil pump alignment, it could effect the oil/gas mixture at certain throttle settings if not aligned properly.

 

[Pnut80]

Tried the Gas cap idea. No luck. could it still be a vent issue? even if i ran without gas cap

 

[mikidymac]

No, if the cap was off then it's not a tank vacuum issue.

 

[Pnut80]

Well Dang, Back to the drawing board

 

[GGuillot]

Well Dang, Back to the drawing board

Above in your first post you stated "new carb" what do you mean by that? did you actually purchase a new carb? I ask because it's not easy to get a new carb, and if you do it's not cheap. Curious why not just rebuild it with an OEM kit.

 

[Pnut80]

Above in your first post you stated "new carb" what do you mean by that? did you actually purchase a new carb? I ask because it's not easy to get a new carb, and if you do it's not cheap. Curious why not just rebuild it with an OEM kit.

yes, Bought new because i don't have alot of free time with work

Bought from OSD seadoo parts.
mikidymac, Recommended thats where i buy it from

 

[mikidymac]

At some point the carbs can't be cleaned and a new one is the answer. I know some people gave up rebuilding them every couple years at $100 a pop and just replace the carb every 5 years for the same price. I have a GTI that no matter how many times and how perfectly I cleaned it it had hesitation off idle. That it every port flowing perfectly, ultrasonic cleaning, soaking for days in carb cleaner and finally I had enough and bought an new carb from OSD an hit has been running flawlessly ever since.

Brand new Mikuni single carb for the 720 is only $209.

 

[GGuillot]

yes, Bought new because i don't have alot of free time with work

Bought from OSD seadoo parts.
mikidymac, Recommended thats where i buy it from

Ok, so it was a bolt on carb, so that should be good.

I'm taking a stab at it trying to assist you in resolving it. My thoughts, might be electrical, but the consistent time mark at 30 -45 minutes having problems doesn't support it. I'd still double check the oil pump alignment, but I don't think that would be your issue either, you'd be fouling plugs, lots of smoke, etc.

It sounds like it's overheating and hear me out, the upper part of engine can be getting cool water so it's not setting off the overheat sensor. The lower portion of the cylinders might not have water flowing out to the very rear exhaust fitting. There's 5/16" tee fitting at the bottom of the cylinders. So if that line is blocked and not flowing, it sits stagnant and eventually heats up to present the problem. It's difficult to see if it's blocked, but see if you can check if the flow is good. Rebuilding my 97' GTX, I found that brass orifice fitting in the very rear exhaust flange to be plugged, little mud diggers clog holes up, especially if it sits outside.

The symptoms seem replicate overheating. I base this off of what I know how engines tend act when they overheat and you describe this with after running for awhile it shuts off, poor idle doesn't want to run and so forth. Then you let it sit (cool off) then it cranks up and runs fine.

I may be way off base, but if the carb is good and it runs fine for the first 30-45 minutes I'm not sure what else to look at.

 

[Pnut80]

Ok, so it was a bolt on carb, so that should be good.

I'm taking a stab at it trying to assist you in resolving it. My thoughts, might be electrical, but the consistent time mark at 30 -45 minutes having problems doesn't support it. I'd still double check the oil pump alignment, but I don't think that would be your issue either, you'd be fouling plugs, lots of smoke, etc.

It sounds like it's overheating and hear me out, the upper part of engine can be getting cool water so it's not setting off the overheat sensor. The lower portion of the cylinders might not have water flowing out to the very rear exhaust fitting. There's 5/16" tee fitting at the bottom of the cylinders. So if that line is blocked and not flowing, it sits stagnant and eventually heats up to present the problem. It's difficult to see if it's blocked, but see if you can check if the flow is good. Rebuilding my 97' GTX, I found that brass orifice fitting in the very rear exhaust flange to be plugged, little mud diggers clog holes up, especially if it sits outside.

The symptoms seem replicate overheating. I base this off of what I know how engines tend act when they overheat and you describe this with after running for awhile it shuts off, poor idle doesn't want to run and so forth. Then you let it sit (cool off) then it cranks up and runs fine.

I may be way off base, but if the carb is good and it runs fine for the first 30-45 minutes I'm not sure what else to look at.

At this point i am up for any advice. LOL I will look into it and see if i can locate and check that fitting
Thanks

 

[Pnut80]

At this point i am up for any advice. LOL I will look into it and see if i can locate and check that fitting
Thanks

No fouling of plugs or excess smoke with Ski running