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1996 GTI 718 Starting Issues

K Huf

New Member
Messages
3
Water Crafts
2006 Bayliner 175 3.0
1996 Seadoo GTI 720
1994 Seadoo GTX
I am new to the Seadoo scene but I have been boating for years. I picked up a pair of Seadoo PWC's, 1996 GTI 717 and a 1994 GTX. The GTX engine is in pieces so I am focusing on the GTI. The issues I am having are as follows.......

Initially when I connected a battery it blew the 5 AMP fuse. After a series of tests I found that it only blew if the magneto was plugged in. Figured that the stator was bad and pulled the flywheel. The stator and flywheel are very clean so I figure they may have been replaced recently. Connected the battery and the starter spins but only with the magneto plugged in. And now the 5 AMP fuse no longer blows. Re-installed the flywheel and it cranks and fires on starting fluid but after releasing the start button it is totally dead unless I unplug the magneto and plug it back in. When I re-connect the magneto plug it starts to crank without the start button being pushed. Then it will crank again. Compression is about 130 PSI on both cylinders.

Not sure where to go from here.
 
Last edited:

GGuillot

Well-Known Member
Messages
930
Location
Alabama
Water Crafts
1997 GTX
1996 GSX
The stator and flywheel are very clean so I figure they may have been replaced recently.
Just because it's clean is not a good way to determine if it's good or not. I'd do an ohm test with a meter, per the service manual guidelines.

Re-installed the flywheel and it cranks and fires on starting fluid but after releasing the start button it is totally dead unless I unplug the magneto and plug it back in.
I wouldn't use starter fluid anymore, just not a good idea on these skis. Sounds like there's definitely an issue with the magneto, so you need to rule that issue out first. Then....go through the fuel system, if you just picked it up I'm sure the carbs need a good cleaning and a through rebuild, wouldn't hurt to replace lines and get some genuine carb kits when you do it. Might be a compounding problem, both magneto and carbs.

I wouldn't stop there, maybe get it running, but before sticking it in the water I'd go through everything, jet pump, ck the bailers, replace the oil injector lines. You don't want to fry the top end or sink it on the first water test.

Compression is about 130 PSI on both cylinders.
Not the best, but it should start and run on 130 psi, but you may need a rebuild sooner than later.
 
Last edited:

etemplet

Premium Member
Premium Member
Messages
2,732
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
You da man figuring all that crap out !! You got the combination. :D 130PSI isn't very good compression but you never know, it may come up after you run it a bit. Generally if the compression is that low you will see some physical damage. My experience anyway.

I'm not much help on the electrics butI would suspect the rectifier with that strange issue and go from there. There may be a small ground wire that connects to the mag cover. Make sure that is in place and it is clean and making good contact. Good Luck.

I think that GTX is gonna have a 657X engine in it. I'm building one of those right now. Boy O Boy I thought I had a good spare engine that just needed some love even with a few broken bolts I had my hopes up. Got to the crank and had to give it up. I had a 1995 that was great for pulling tubes and such, better than the 1996 GTI. It had some grunt !! Not fast tho. Good luck with that one.
 

GGuillot

Well-Known Member
Messages
930
Location
Alabama
Water Crafts
1997 GTX
1996 GSX
I would suspect the rectifier with that strange issue and go from there.
Rectifier? How did you arrive at this assessment? He's barely got it running with starter fluid so far...

I wouldn't throw money at swapping the rectifier at this point, he has no way of testing it until he can get it running with a stable idle on the hose.
 

K Huf

New Member
Messages
3
Water Crafts
2006 Bayliner 175 3.0
1996 Seadoo GTI 720
1994 Seadoo GTX
I tested the generator coil which per the shop manual is the black/red and black wires, has 50 ohms. The charge coil, yellow/black and yellow wires, has 0.6 ohms. all within specs according to my shop manual.

Yes, replacing fuel lines, rebuilding the carburetor, are all on my list but need the figure out the electrical issue. The strange thing is the 5amp fuse blowing at first but now is not blowing. Also after cranking and firing I have to unplug and re-connect the magneto before it will crank again.
 

GGuillot

Well-Known Member
Messages
930
Location
Alabama
Water Crafts
1997 GTX
1996 GSX
I tested the generator coil which per the shop manual is the black/red and black wires, has 50 ohms. The charge coil, yellow/black and yellow wires, has 0.6 ohms. all within specs according to my shop manual.

Yes, replacing fuel lines, rebuilding the carburetor, are all on my list but need the figure out the electrical issue. The strange thing is the 5amp fuse blowing at first but now is not blowing. Also after cranking and firing I have to unplug and re-connect the magneto before it will crank again.
Run down all the ground points on the ski, typically when unplugging/plugging something to reset it can be ground issue related. Typically there's a ground point in/at the MPEM (ECU), the battery, the starter and the engine, which will all tie in together.
 

etemplet

Premium Member
Premium Member
Messages
2,732
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
Sounds like your coils are good. :) Not being an electronics guy but what blows the fuse is when voltage tries to come through the back door. I had a rectifier issue on my SPI (1996) that fried the MPEM. Actually blew the diode along "with" the 5 amp fuse. It was easy to find as the rectifier was dead shorted internally. Something is leaking voltage. I'd check the start/stop switch but rectifiers don't cost all the much.

You could test the MPEM's indiviual wires. Then you may have to get into the connectors to the wires in question. Doesn't sound like the problem is your MPEM but you never know.
 

K Huf

New Member
Messages
3
Water Crafts
2006 Bayliner 175 3.0
1996 Seadoo GTI 720
1994 Seadoo GTX
MPEM is new. Next free time I get I will check all the ground points.
 

etemplet

Premium Member
Premium Member
Messages
2,732
Location
Louisiana
Water Crafts
1996 SPI, 1996 GTX, 1997 GTX
Wow Good luck man !!! The electronics on these skis will take you to school.... I got a couple right now.
 

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