RESTO Carb adjustment

[Chrisd1234]

Gentleman I am having trouble adjusting my carbs and I was wonder which screw is what on the carb it’s a 1996 seadoo gtx 787 and how many turns out they should be

 

[JeremyD615]

The low speed screw, the one with the Tee adjuster on it, should be one full turn out from fully closed. The high speed screw, the small one on the opposite side of the carbs, should be fully closed. The popoff spec is 23-43psi. I hope that helps.

 

[Chrisd1234]

Yes it does thank you I appreciate it

 

[Chrisd1234]

I’m having some technical difficulties with i was running it pretty hard and the mag piston flooded out but the pto piston did not I also just loosened up the oil line that I had way to tight so hopefully after some adjusting it will run good

 

[JeremyD615]

Well in that case, make sure you check to see where the carb needles are set now. If they are way out of adjustment, that could be your issue, but if they’re at or close to the factory settings, we need to dig in and see what’s causing it.

 

[mikidymac]

If one cylinder flooded out you have a major carb issue, not an oil issue and you need to take the carbs apart and check.

 

[Chrisd1234]

Ok so I should be 1 full turn out on the lows and 0 on the highs

 

[JeremyD615]

Yes, that’s where they should be set. You really need to go through them and see what the cause of the one cylinder loading up is though...

 

[Chrisd1234]

Ok yea it doesn’t make sense because it only fouls out after running it full throttle

 

[Chrisd1234]

So just an update my mag piston was 2 turns out

 

[JeremyD615]

On which screws?

 

[Chrisd1234]

The low speed

 

[JeremyD615]

That should not be enough to cause the loading up on that cylinder that you’re describing. Unfortunately I think you’re looking at something more serious than a carb adjustment...

 

[JeremyD615]

I’d start by pulling the carbs and installing fresh OEM Mikuni carb kits along with new needles and seats. Reuse the old spring for the needle arm, and see if that does it. Follow the carb rebuild sticky and it’s a pretty simple process.

 

[mikidymac]

The low speed

The low speed screw does absolutely nothing once you touch the throttle. It only adjusts the idle mixture when the throttle is closed. You have something else wrong with your fuel system.

 

[Chrisd1234]

Could it also be that I had to oil adjustment set way to tight or would that just make it make it smoke a little more and not effect it

 

[mikidymac]

It's possible if it was dumping full oil all the time.
Although I have seen a few skis run perfectly fine with a broken cable causing the pump to give full oil all the time and all they did was smoke a little more than normal. It should not foul a plug at WOT.

 

[Chrisd1234]

I rebuilt carbs with genuine Mikuni rebuild kit followed all the specs as per the book and I melted the crown of the pto piston I think I’m going to go with a oil block off plate and go premix

 

[Chrisd1234]

Or sink it

 

[mikidymac]

I rebuilt carbs with genuine Mikuni rebuild kit followed all the specs as per the book and I melted the crown of the pto piston I think I’m going to go with a oil block off plate and go premix

Premix won't help if you are running lean, you'll just melt the new pistons also.

 

[Chrisd1234]

What else could cause a lean condition the whole motor is rebuilt upper and lower

 

[Chrisd1234]

The only thing I could think of is an oil issue that I’m not getting enough to that piston the mag looks great the pto piston is practically dry

 

[mikidymac]

If it is dry, it's a fuel issue.

Did you rebuild the carbs with genuine Mikuni parts?
Did you test pop-off and leak down on the carbs?
Did you replace the fuel selector and strainer o-rings?
Are you running the gray Tempo fuel lines?

The oil pumps don't typically fail. Is oil filling the little 3/32" oil lines?

 

[Chrisd1234]

I checked all of that and used the Mikuni parts I replaced all the gray lines last year with new black ones and I can see oil in the lines I’m completely at a loss with this thing

 

[JeremyD615]

Check your transition ports very carefully as well. They’re very hard to get completely clean!