1997 GTI backfiring out carb. Help!

[Thomas01]

Hello, I am having problems with my 1997 717 GTI backfiring out the carb when on the water. Runs fine on the trailer. Doesn’t do it at idle, only when you try to give it gas and go. I have checked everything I can think of. The rotary valve does have some scratches on the case but nothing major. Rebuilt the carb using SBT rebuild kit. Checked it and rechecked it. Everything is set perfect. Would that cause backfires. I’m going crazy trying to track the cause down! Help! Thanks.

 

[mikidymac]

1997 GTI isn’t injected, just a damn simple carbed 720.

I would start with a new voltage regulator.

 

[Thomas01]

I ordered a new voltage regulator. What about the stator? Thanks.

 

[POPPS]

Theoretically you would test out the stator first,,,if it is not working,,,then the reg can't regulate,,,also check the front plug for corrosion,..both sides...

 

[Thomas01]

Theoretically you would test out the stator first,,,if it is not working,,,then the reg can!t reg,,,also check the front plug for corrosion,..both sides...

Going to work on it more tomorrow. Probably change out the stator with another one I have. Do you think it’s the stator that would make it backfire out the carbs while trying take off on the water? Also the voltage going up and down on the battery while it’s running on the trailer? I’ve seen it go from around 12.7 to 1.5 and back up especially while revving it. It constantly changes voltage at the battery. Thanks for any help!

 

[Thomas01]

I got a new rectifier, no difference. Voltage still jumps up and down while testing on the trailer. I’m using a digital volt meter with the leads directly connected to the positive and negative connections at the battery. What would cause different voltage readings? Really strange. I will check the carb settings to make sure it’s not lean also. I have a video of it backfiring on the lake but I don’t know how to upload it to this site. Thanks!

 

[POPPS]

Okay,,,test the stator,,the stator may be doing tricks,,,it produces alternating current for the rectifier to change to dc.

 

[Thomas01]

Okay,,,test the stator,,the stator may be doing tricks,,,it produces alternating current for the rectifier to change to dc.

Ok changed the stator and voltage regulator. Double checked everything. Still the same. Runs great out of the water. Put it in the water and backfiring out carb at about 1/4 throttle. What else could it be? Checked the carb settings they are perfect. I do have light groves that go all the way around in the rotary valve housing. Could that be the reason? I’m going crazy trying to figure it out.

 

[Thomas01]

Could it be the Ebox ? Maybe the rev limiter?

 

[Thomas01]

Could it be the Ebox ? Maybe the rev limiter?

So the voltage problem I thought I had was a faulty cheap multimeter. So that’s not it.

 

[Thomas01]

Anybody??

 

[ALLLCAPSRAGE]

I had backfiring out the carbs on my hx I changed the plugs and set carb settings to stock and ran it for a bit then fine tuned the carbs by doing plug chops at wot Sea Doo PWC Carburetor Reference

 

[Coolride17]

Try plugs, and start it at night , and look for electrical arcing from the plug wires or boots.