RX DI stalls after riding for a while

[greggri79]

Hi everyone. This is my first post. Thanks in advance for any help with my issue. I have a 2001 RX DI. I bought it brand new back in 01' and it has been a great ski. Haven't had a single issue other than a couple of wear rings. Last weekend I took it out and it ran great but started losing power. Let it sit for 15 minutes or so and it would run great. Started getting worse to where it would start and only run for a few seconds. Had to tow it back in with my other ski. I ran it in the driveway with a water hose for over a hour with no issue. I had a fuel pressure guage attached. 30psi with key on. 110psi while running and applying throttle. After some time, my fuel pressure guage started rapidly fluctuating from about 75 to 110psi. This didn't effect the engine sound, rpm or applied throttle. Any ideas as I am not familiar at all with this fuel/air system? Side note: cylinder compression is 90psi on one and 100psi on the other. Thanks again for any guidance

 

[etemplet]

Have you ever replaced the fuel filters in the canister inside the fuel tank. There is also another fuel filter outside the tank. If you have not, those filters are 20 years old and can disintegrate. Your fuel pressures are great and if they are bouncing around... you are cavitating. I replace all of the filters and maybe drain the fuel from the tank. Sounds like the ski just needs some love. I love the DI's they are bad azz. Good Luck with it.

 

[WaarrEagle]

You should not run it on a hose for that long. You will cook your carbon wear ring.

If your fuel pressure checks out, I would take a good look in the cylinders. At that age and if an original motor, it wouldn't surprise me if your issue is in that direction. With my first rebuilt engine, I had okay compression but it would not fire on one cylinder. Turns out a small chunk was missing from the edge of the piston.

Your DI should fire on 1 cylinder. Try unhooking each spark plug and see if it will run.

 

[greggri79]

Have you ever replaced the fuel filters in the canister inside the fuel tank. There is also another fuel filter outside the tank. If you have not, those filters are 20 years old and can disintegrate. Your fuel pressures are great and if they are bouncing around... you are cavitating. I replace all of the filters and maybe drain the fuel from the tank. Sounds like the ski just needs some love. I love the DI's they are bad azz. Good Luck with it.View attachment 65651

I actually have a brand new pump and filters that I'm going to install next week. I love my DIs'! Thanks for the info

 

[greggri79]

You should not run it on a hose for that long. You will cook your carbon wear ring.

If your fuel pressure checks out, I would take a good look in the cylinders. At that age and if an original motor, it wouldn't surprise me if your issue is in that direction. With my first rebuilt engine, I had okay compression but it would not fire on one cylinder. Turns out a small chunk was missing from the edge of the piston.

Your DI should fire on 1 cylinder. Try unhooking each spark plug and see if it will run.

I'll definitely check that. Maybe with a bore scope? Is there any way to mitigate the wear on the ring while out of the water? Maybe install a second hose in the impeller intake or jet nozzle?