1997 GTX 787 won't start up, misfires

[1997GTX83]

I have a 97 GTX(51hours) with the 787 engine and it won't start up at all.

My ski was running fine and 2 month ago it just shut off on the lake and didn't want to start back up. I've done a compression test a few days later and had 147psi in the front and 0psi in the rear cylinder. I ordered a remanufactured engine from SBT and a new oil pump from the seadoo dealer and replaced everything. The engine alignment was done by a dealer and I've done the rotary valve timing myself(146.5). The ski was running after all was done and I was able to break in the engine. After the break in was done the ski was only going 50mph at 5700rpm max.

I was able to ride it for 6 hours and then it startet loosing constantly power and the rpm's where going up and down when hitting the throttle. I was able to idle home but the idle was rough(between 970 and 1430rpm). One day later I was trying to ride it but it bogged down when I was hitting the throttle and i had to swim the ski back:willy_nilly:. The idle was still rough and the engine noisy and vibrating. A day later my starter was running irregularly, and shut off by itself with a loud hammering noise. I took one spark plug out and the starter was turning but not like usual with a consisting speed. Like something is switching between 7 to 12V. I replaced the starter with a new SBT starter, rebuild and readjusted the carbs and replaced the gray fuel lines. I'm still using the old little springs in the carbs because I have no pop off tester but I took the needle out and sprayed some WD40 on it..

Now my ski won't start up and misfires when i play with the throttle and try to crank it. The new starter was working fine but after a couple times trying to start the ski was he running irregularly too.
When I reconnect the lanyard the starter runs once or twice normal.
The compression is 150PSI in both cylinders, fuses are good, oil pump, starter and fuel lines are replaced, the battery is tested and good, carburetors are rebuild with 2 mikuni rebuild kits, fuel filter cleaned, Ignition tested

Can a rotary valve get out of timing by itself(146.5)?

Wrong carb adjustment?(both LS screws -1 turn, high speed screw had no plastic cap so I adusted it to pto 0 and mag -0.5 turn)

Electrical issues?(rectifier, mpem)

Any suggestions? Help would be greatly appreciated.

 

[seadoosnipe]

Nice write up!

It sounds like your problems are going to involve the grey fuel lines. Once these lines start to decay, they can cause problems even after you do the rebuilds and clean everything out. I doubt very seriously that you have a problem with your rotary. If you know you put it on correct, it can't jump teeth.

Get some fuel from your weedeater or chain saw. Pop out the plugs and put about a half teaspoon in each cylinder and give it a go. If the motor starts and runs for a few seconds and shuts down, then your problem is still in the fuel circuit.

You can also get a short piece of fuel line, run it from the outlet side of the plastic fuel filter, then run it directly to the fuel pump on the mag carb. By bypassing your fuel selector valve, you might find the problem is there or somewhere in between.

Before you put the fuel into the cylinders, lay both the plugs on the side of the engine, attached to your plug wires. Turn the motor over and see if you have spark jumping across both plugs. If one or both look weak, trim about a half inch off each wire, then put the boots back on......

I have this same ski.. I love it! It will haul butt. Mine has hit a peak speed of 61. So, get the fuel circuit back in shape and you should be fine....:cheers:

 

[1997GTX83]

took your advice

Thank you for your quick answer, I took your advice and that's what my ski is doing right now.
I went to my ski, pulled the spark plugs out and put the boots on. The first time I've tried starting the ski I've seen a weak spark and after that I didn't see a spark at all. I've put half a teaspoon gas in both cylinders and put new spark plugs back in and it didn't crank up. I was trying it a couple times and now my starter is not turning anymore, all I hear is a "klack" noise(new starter). I thought my battery is weak, but I see on the black battery connection when I try to start it up that it is smoking. When I touch it it is hot. I opened the fuse box next to the battery and a metal piece dropped down while I was touching it. I think this piece has something to do with the grounding device. I put that piece back in but it seems to be loose. I've never messed with it, so I don't now if it has to be loose or something connect's to it. Do you have any suggestion what to do next?

 

[1997GTX83]

re

I walked down to my jet ski slip again to take out my battery, and I noticed my black battery cable became loose. I tightened it up and the starter was turning again. But I still have no spark on the plugs . After a few times of trying to start the ski, my starter is doing a quiet indescribable noise(suuummm). Also when I hook up the lanyard to the ski again, the screen goes on but it won't tell me how much fuel is my tank. I've never had that before.

Is it normal that the connections to the battery get hot/warm when I try to start it? I took the battery out and will charge it over night.

I hope you have an idea what to try next, and what can cause my spark plugs not to spark. Tomorrow I will trim the spark plug wire and try it again.

 

[1997GTX83]

can't turn engine by hand

I've trimmed the cable on the spark wires and I still get no spark, but I think I found my main issue now.

Now my engine and starter won't turn at all.
I've done a compression test just 2 days ago and I've had 150PSI on both cylinders. My starter wants to turn the engine but he is not able to turn it and makes a weird noise . I've tried to turn the engine by hand(plugs out) like I was doing it when I set the timing for the RV but I am not able to turn it by hand anymore.

What can be the reason that I can't turn my engine anymore by hand?

This was maybe the cause that my starter ran "irregularly", for the rpms jumping up and down and bogging down the ski.

Seadoosnipe can you help me out? I've read many of your threads for example "a look inside the 787", and I know that you know a lot about the 97 gtx and the 787 engine. Any more help would be greatly appreciated. :cheers:

 

[Chris488994]

Hello bud I was just wondering if you figured out your problem?

Could be a possibility that your starter overheated and siezed up with the bendix stuck to the flywheel. Stopping the motor from spinning by hand.

Good luck. I hope its somthing simple like that. Let us know.

 

[1997GTX83]

The gear at front of my starter stucked and didn't slide back anymore. That's why I couldn't turn the engine by hand anymore. I've got a replacement starter(warranty) from sbt, but I still have issue's. I've bought an ignition(inductive) timing light, and figured out that I'm only getting sporadically spark.
I'm not getting constantly spark when I try to crank the ski. I get sparks for a second and then I'm not getting spark for about two seconds and then it sparks again.
I'm gonna check the ignition coil today with a volt meter.
Is there anybody who has any suggestions about my issue?
Any help is greatly appreciated

 

[Chris488994]

Cool I was right about the starter being stuck in. You lucked out on that one bud. Lol.

As For the spark, try disconnecting the red wire of the rectifier in the front gray box. It's the little aluminum box that has 1 red, and 3 yellow wires coming out of it.

When they go bad they mess with the ignition and spark systems.

Good luck bud.

 

[1997GTX83]

Maybe you are right again

Thanks for your quick response bud, you might be right again. :cheers:

I remember a while back, that I was messing with that red wire on the rectifier. I was trying to disconnect the connector, but wasn't able to get it apart. I've pulled on it very hard, but it didn't come off.

Do you know how to get those connectors off?
Is there a way to disconnect the connector without cutting it off?

 

[Chris488994]

Yeah it should just be clear rubber covers. You need to get a small screwdriver and pry between the two then spray a little WD-40 in there and twist. They should just pull apart after that.

The two rubber parts just get stuck together after awhile.

Good luck.

 

[1997GTX83]

I took the red wire on the rectifier off but it makes no difference. I've also checked the resistance on the ignition coil(0.43ohm) today and on the spark plug wires(12.7kohm) with the boots off. Here is exactly what my ski does right now.

When I try to start my ski, I get spark on the spark plugs and then my starter makes a loud "hammering" noise and quits turning. Sometimes it sounds like the starter spins free after that loud noise. It also backfires sometimes and some water sprays out of the exhaust.

I'm guessing that something with my ignition or magneto is wrong. Is that possible. The ski was running after I replaced the engine , but it only rev up to 5500rpm.
Can a wrong ignition timing cause the engine not to start. (it was running before)?

Any ideas?

 

[1997GTX83]

Problem resolved

A bad stator caused my spark/ignition issue. I've replaced the stator with a used one from ebay and it runs like a champ now.

 

[Chris488994]

Wow congrats Bud. Glad to hear you fixed it. Just a couple questions that could possibly help out other people.

How did you figure it out?

Did you test it on the ski?

Did unplugging the rectifier help at all? Or did it still fail?

Was your charging system still working? Does it work now?

How much was the part and was it hard to change?

Once again I'm glad u figured it out. I'm sure other people are scratching their heads over this problem.

 

[1997GTX83]

This can be symptoms of a bad stator:
- no sparking at all
- sporadically sparks when you hit the start button
- erratic operation when the ski runs
- will not charge the battery (lighting coil open)

How did you figure it out?

I met a guy at my apartment complex who works for my local seadoo dealer. He thought my stator is bad after I told him about my issue. So he brought an adapter home from work and we checked the stator.
This is what needs to be done to check the stator on a 787 engine:

Stator
STATIC TEST: CONTINUITY
1. Disconnect the magneto wiring harness con- nector.
2. Install the six-pin magneto harness adapter (P/N 295 000 136).
3. Check resistance between two of the YELLOW wires. The resistance should be between 0.1 to 1.0 ohm.
4. Place either meter lead into the remaining YEL- LOW wire and note the resistance (same as step no. 3). If the readings are out of specifica- tion, the stator will need to be replaced.

STATIC TEST: INSULATION
1. Disconnect the magneto wiring harness con- nector.
2. Install the six-pin magneto harness adapter (P/N 295 000 136).
3. Insert multimeter + lead to one of the YELLOW wire of the six-pin magneto harness adapter.
4. Ground the multimeter – lead to the engine or the stator iron core and note the reading.
5. Repeat test with the other two YELLOW wires of the six-pin magneto harness adapter.
NOTE: There should be no continuity (infinity) be- tween the stator insulated coils and ground. If there is a reading, the stator coils and/or the wir- ing from the coils is grounded and needs to be replaced or repaired.

Did you test it on the ski?

Yes we've done the static test and noticed that we are out of specification.

Did unplugging the rectifier help at all? Or did it still fail?

Unplugging the rectifier didn't change anything. The spark was still intermitted, and this was caused by a faulty stator.

Was your charging system still working? Does it work now?

The charging system was working before the issue and it still works. I can't tell for sure if it wasn't working, because after my ski started to run irregularly, I was only able to ride it home at idle speed. After that it fired up a few more times and then all for sudden it didn't start up anymore. I guess it wasn't working because I had to charge the battery, after a few times trying to crank the ski.


How much was the part and was it hard to change?

He told me that a new stator is around $300 at the seadoo dealer, but I might can get a used one cheap on ebay. I decided to get a used one from ebay for $85.

It was not complicated to change the stator. This is basically what I did.
Usually the stator comes by itself, but my used stator came still mounted in the magneto housing. The easiest way would have been to change just the housing, but I was not sure if it seals properly.
I took the oil pump off. After that I took the outside cover off the magneto housing and replaced my old stator with the used one from ebay. Then I put everything back together and checked the alignment for the oil pump.

After that my ski started up. I also adjusted my carbs, because I've rebuild them a while ago and they needed to be adjusted. Then I put the ski back in the water and ran it for a while. It hit peak speed of 62mph for a second, so everything seems to be fine now. :cheers:

I hope this helps somebody with a similar issue.