GTX 787 RFI won't rev over 4700rpm

[Seadoo787GTX]

Hey everyone.

My new to be 787 RFI 2002 is being a pain. It won't rev above 4700! Sometimes have maint light on but even when it soft it's the same..

It will not rev above 4700, no splutters or misfires, just 4700! On the hose it's fine.

Sometimes on the hose though she. The maintenance light comes on, it will bog unless I very gently throttle up. If I hit the throttle even close to hard it bogs and cuts out.

It's charging at 14v, tried 2 (new) rectifiers so it's not that.

Desperate to get out and use this before the end of season so any advice appreciated.

Thankyou

 

[Seadoo787GTX]

Bump please

 

[mikidymac]

Have you tried changing the fuel filters?
Chang the spark plugs and trim the plug wires back 1/4"?

 

[Ckrawiec]

Not 100% sure this is a relevant thought anymore....but is/was there still a "Learner's" key VS a "Regular" key in the 2002 vintage? The Learner's key will retard a ski's performance.....just a WAG (wild ass guess)......OTHERWISE, bogging is usually a symptom of a fuel delivery issue.

 

[mikidymac]

The only 2-strokes that had the learning key were the DI ones.

 

[Seadoo787GTX]

Right so I'm getting somewhere guys, done AC voltage test out of stator and got 10v! £200 later I got a brand new stator on.. still getting 10v? I'm stumped!

Out of the rectifier I'm only getting 2v (tried 2 new rectifiers)

Wiring from stator to rectifier plug seem good too?

 

[Seadoo787GTX]

Sorry didn't see you're above responses. I'm sure it's an issue as it's bogging on the trailer now when the maintenance light is on. Idles fine but any revs and it will bog and die?

 

[Seadoo787GTX]

So, very strange but it now revs and is responsive (maint light on)

The output voltage from the rectifier (disconnected from battery) is massively fluctuating between 8 and 13 volts! When it's connected to battery, battery charges at 13.2v (low?)

 

[POPPS]

Have you checked every connection starting at the battery?

 

[Seadoo787GTX]

I believe so! Been over pretty much every plug on the ski. I think I'm going to buy a new battery. The one on there is a bit small, it's from my quad bike. Worth a try I guess

 

[POPPS]

I can tell you from experience,,,that once cost be large salad bowl of spark plugs,,,the BATTERY is EVERYTHING!,,,put in the biggest that will fit in the battery rubber receptacle.

 

[etemplet]

I don't have the equipment to do this but after the new battery I'd check the current draw on the fuel pump.

 

[POPPS]

Good call etemplet,,,when the electric fuel pumps start to fail, they will draw more current from the system,,,this "may" explain the fluctuations in the voltages,,.when a rectifer is totally gone, the battery output voltage will be at a "steady/fixed " less than 12 volts reading,,,this will mostly occur when a fuse that protects the battery charging circuit is blown,,,when rectifiers go,,,they still charge in the 12 volts range, but will not reach 13 plus volts.​

 

[etemplet]

Good stuff Popps. Thanks for posting.

 

[Seadoo787GTX]

Hey guys. Sadly I'm losing interest because of this so only got back out tonight. After a new battery and another check of everything I'm charging at a steady 13.4v. a little low I believe? But stead. Revs freely now (on The trailer)

it does however have a rough ideal and bizarrely enough, the front cylinder plug was not black at all but the rear was almost like the front cylinder is not doing anything?

rear rave valve filthy, front was clean?

i checked resistance in coilpack primary side and I'm getting 0.020k ohms. That's 2 ohms isn't it? Manual states between 0.36 and 0.46 ohms? Therefore I'm out?

 

[etemplet]

I'm not sure how often those coils go bad. I've chased a few issues where it thought it was the coil. It never was. I restore the skis so I generally remove the front mag cover and clean everything or make sure everything looks OK. Most times it is really pretty inside. If moisture got in there at some point... it can get really ugly. If you have not opened it up yet... take a look. Good Luck

 

[Seadoo787GTX]

It has a brand new stator. Old looked nasty so replaced it. Stator, battery and rectifier all brand new?

Thanks