787 GTX Carb Settings

[Jeff_5_7]

MY 787 in my GTX fouled my brand new set of plugs in about 5 minutes. I pulled them out and they were dark glossy black and wet. When the fouled the ski would only run about 5000rpms and started back firing.

How do i need to set my high and low jets?

I thought lows were all the way in then 1 1/4 turns out and highs were all the way in 1/4 out. My plastic caps are gone off my highs.

How can i fix this i almost sure its because i am running to rich. I am also runing premix at 32:1

 

[kustomkarl]

The correct oil ratio is 40:1 The low speed screw should start off at about "2 1/2" turns, and the high speed screw should be at "0".

The injector pump injects oil at at variable rate, while premix uses more oil and could foul plugs from low speed use.

Karl

 

[Jeff_5_7]

I am running 32:1 as i am still breaking in this motor then i will switch to 40:1.

So 2 1/2 turns on the low?

On the high since the plastic cap is gone i should just turn it all the way in?

 

[Chris488994]

In my 1997 GTX manual it says to set the lows at 1 turn out and the highs are 0 (all the way in) on the MAG and 1/4 on the PTO.

 

[Mathews_1]

In my 1997 GTX manual it says to set the lows at 1 turn out and the highs are 0 (all the way in) on the MAG and 1/4 on the PTO.

I believe Chris is correct, my 96 GTX manual says the highs are 0 and the lows are 1 1/4 out.

 

[kustomkarl]

Typically, when you adjust the carbs you will be adjusting them to run properly anyway. The 2 1/2 turns on the low speed is just a starting point. You always need to adjust the carbs based on how it is running. The high speed screw usually has a plastic cover on it to prevent it from being adjusted more than 1/4 turn out. The high speed usually never needs to ever be more than that.
Be sure both carbs are the same adjustment and in sync with each other.

Karl