2003 Seadoo GTX-DI Won't Start

[ParamedicCurt]

Here's the situation:

2003 GTX-DI (Rotax 951) with only 86 hours. It had low compression, bad fuel pump and bad air compressor.

New WSM top end - 128 and 119 compression now

New WSM air compressor - good compression now

New fuel pump - good fuel flowing to the rail now

The fuel rail has been cleaned. All the O-rings have been greased and feel good and tight.

No error codes

Had a spare set of injectors so I swapped injectors - it ran for about 20 seconds (just twice) very rough. No throttle control

Cleaned the check valve and solenoid (they didn't appear to be dirty inside)

New spark plugs, properly gapped

New Battery

No large draw on battery when cranking

After ALL that, it still won't start. I even checked to see if there are codes that aren't triggering a maintenance light. There are none according to the display. The best result is when I changed injectors. It acts like it wants to fire, but just doesn't.

Could it be an ignition coil? I went to Harbor Freight tonight to get an in-line tester and they closed 4 minutes before.

Should I try replacing the check valve and solenoid?

Could there be something in the MPEM that needs to be reset? On YouTube I saw the Seadoo Refurb guy from Canada use Can-doo Pro on the same year ski reset something (after doing a complete rebuild) and it fired right up. How much would a repair place charge to do that?

I'm determined now to not let this thing beat me!

I'm very vested now.
- New handle bar grips installed
- New deck mats installed
- New bearings, couplers and tires installed
- All the waxes and pads to take the oxidation off the hull and refresh all the black plastics
- Heat gun and Goo Gone to get the old ugly stickers off

Any ideas?

 

[etemplet]

Did you check the fuel pressure? You can buy adapters to test the pressure. You may have an o-ring leaking. Make sure you have the rave valve solenoid properly connected and the lines are in the correct places. Definitely get a spark checker. I wouldn't worry right now about resetting anything with the Candoo. All my DI issues were solved without the Candoo. If it is trying to start your problem is likely fuel. Good Luck !!

 

[ParamedicCurt]

Well, I found one issue. I had the air compressor and RAVE valves backwards. Still no go though.

 

[etemplet]

Sneaky SOB ain't it? LOL I remove mine so I don't damage the solenoid when I'm removing and installing the engine. Last one I installed reverse. very strange running to say the least but when I realized it, it all made perfect sense.

That's great information in the post though. Lotta lines going to that solenoid. Plus 5 on the explanation.

 

[Jeff Berner]

Did you use factory fuel pump, got to no fuel pressure, or you will be spinning your wheels

 

[Jeff Berner]

Got to be 107PSI or will have issues

 

[tkarvelis]

Try putting a bit of fuel in the jugs and see if it fires. It will point you to the correct road. Remember, compression, fuel, and spark. Make sure the plug and injector wires are correct. He used a CanDoo to reset the TPS. The TPS will not prevent it from running. It will keep you from getting good RPMs and affects air/fuel ratios

 

[POPPS]

Agree with karvelis,,,throw some premix in the cylinders,,if it fires quickly,,,its probably the aftermarket fuel pump,,,,i have never had one work for me,,,unless your compression gauge is way off,,,those numbers are worrisome,,,DI should be around 135.

 

[tkarvelis]

It should run with 128 and 119 lbs compression. For a new top end that the rings are not seated, they will be lower, but 119 seams a bit low.

 

[burtshaver2021]

Here's the situation:

2003 GTX-DI (Rotax 951) with only 86 hours. It had low compression, bad fuel pump and bad air compressor.

New WSM top end - 128 and 119 compression now

New WSM air compressor - good compression now

New fuel pump - good fuel flowing to the rail now

The fuel rail has been cleaned. All the O-rings have been greased and feel good and tight.

No error codes

Had a spare set of injectors so I swapped injectors - it ran for about 20 seconds (just twice) very rough. No throttle control

Cleaned the check valve and solenoid (they didn't appear to be dirty inside)

New spark plugs, properly gapped

New Battery

No large draw on battery when cranking

After ALL that, it still won't start. I even checked to see if there are codes that aren't triggering a maintenance light. There are none according to the display. The best result is when I changed injectors. It acts like it wants to fire, but just doesn't.

Could it be an ignition coil? I went to Harbor Freight tonight to get an in-line tester and they closed 4 minutes before.

Should I try replacing the check valve and solenoid?

Could there be something in the MPEM that needs to be reset? On YouTube I saw the Seadoo Refurb guy from Canada use Can-doo Pro on the same year ski reset something (after doing a complete rebuild) and it fired right up. How much would a repair place charge to do that?

I'm determined now to not let this thing beat me!

I'm very vested now.
- New handle bar grips installed
- New deck mats installed
- New bearings, couplers and tires installed
- All the waxes and pads to take the oxidation off the hull and refresh all the black plastics
- Heat gun and Goo Gone to get the old ugly stickers off

Any ideas?

When you did the top end rebuild did you have the cylinders bored or did you put pistons and rings into the existing bore.? That seems like a fair size difference in compression between cylinders.? I noticed in your new thread today that 2 cylinder is down to 99 pounds now? I didn’t want to post on your new thread so that it would still show zero replies and someone who knows might check for posts with no replies, I was just curious about the boring? Good luck Curt, maybe it’s not time to give up yet? Sounds like you e put a lot of work into the machine.

 

[ParamedicCurt]

When you did the top end rebuild did you have the cylinders bored or did you put pistons and rings into the existing bore.? That seems like a fair size difference in compression between cylinders.? I noticed in your new thread today that 2 cylinder is down to 99 pounds now? I didn’t want to post on your new thread so that it would still show zero replies and someone who knows might check for posts with no replies, I was just curious about the boring? Good luck Curt, maybe it’s not time to give up yet? Sounds like you e put a lot of work into the machine.

I installed new pistons. I didn't not bore it. The cylinders were in mint condition. The new compression readings are 117 and 107. BUT, as I was retracing my steps I noticed in my pictures of the old pistons a different marking than what I installed. (see attached) I installed a STD piston. I'm trying to figure out if these are different sizes pistons and if it is now outside the tolerance and that's why it won't start?

 

[burtshaver2021]

I installed new pistons. I didn't not bore it. The cylinders were in mint condition. The new compression readings are 117 and 107. BUT, as I was retracing my steps I noticed in my pictures of the old pistons a different marking than what I installed. (see attached) I installed a STD piston. I'm trying to figure out if these are different sizes pistons and if it is now outside the tolerance and that's why it won't start?

I re read your newest thread, it does sound like you put a standard size piston in instead of boring and going a size over. I believe this could be your problem as you do have low compression now after the new pistons and rings? Did you have any measurements taken of the notes before to see if they were within spec? Out of round? Especially important when compression readings are different from each other. Also noticed that your compression has went down since the pistons and rings? Possibly a no oil issue. It wouldn’t matter much with bored being out of spec but was the cylinder wall to piston clearance measured and ring end gap? I think if you were to have the cylinders bored for over sized piston and make sure oil delivery is good you would have a good machine there. You’ve already went so far, good luck

 

[ParamedicCurt]

I'm not sure what the measurements were. That was above my skill level. After now doing some research, it seems a made a huge mistake.

 

[burtshaver2021]

I'm not sure what the measurements were. That was above my skill level. After now doing some research, it seems a made a huge mistake.

Your only out the cost of the pistons, rings, and I wouldn’t think there would be anything wrong with pistons, wrist pin and caged needle bearings, you could try and sell those for 75 percent. If you plan on making this a hobby you could buy a dial bore gauge and right sized caliper so you can do your measurements and a set of feeler gauges.if not a local shop can do this for you

 

[etemplet]

What does the top of the piston read, (.25) (.5) ??