96 GTX carb tune question

[Legacy37]

I Figured out my shutoff issues and fixed them. Ski has 165 psi compression both cylinders. Both carbs rebuilt per the sticky thread pop-off 36/35 all 3 holes in throat clean and flowing. Starts and idles fine in the water. Off idle to 1/2 throttle it falters and will stall. If I feather the throttle to wide open it runs hard and strong. I am unsure if it is going too rich or lean? Plugs look great. Had an identical problem with my single carb 717 and it was a low speed screw adjustment. Would like to add the low speed screws were set to factory 1 turn out…not sure if 165psi is factory compression.

 

[mikidymac]

Perfect compression is 150 psi, could just be the gauge.
You can try pulling the choke a little to see if it gets better or worse. Backing out the LS screws 1/2 turn can't hurt anything.

 

[Legacy37]

Perfect compression is 150 psi, could just be the gauge.
You can try pulling the choke a little to see if it gets better or worse. Backing out the LS screws 1/2 turn can't hurt anything.

The head appears to be after market not sure if that changes things, I will check gauge but its not a cheapie harbor freight. My concern is going lean. 1/2 turn out is richer…either it gets worse or much better. Choke does seem to help some

 

[mikidymac]

Any other performance mods than the aftermarket head like air cleaner?

 

[Legacy37]

Factory air cleaner

Any other performance mods than the aftermarket head like air cleaner?

 

[Legacy37]

Took a little while…Had to remove the carbs to make low speed adjustments…cant see the screws in the 787. Anyway backed both screws out 1/4 of a turn so total 1.25 turns from full in. Ran great hesitation is gone. Thank you….this site is amazing

 

[cloudmaster_321]

I'm having similar issue, but not as bad as yours. I'm also at 1 turn out. Planning to go 1.5 our on each low speed to see what happens. 97 GTX 787

 

[Rob Dog]

I'm having similar issue, but not as bad as yours. I'm also at 1 turn out. Planning to go 1.5 our on each low speed to see what happens. 97 GTX 787

How did it go? Mine are at 1 1/2 and it is sluggish on take off... going to 1 1/4 ......

Update... Went to 1 1/4 and it got worse.... Now at 1 5/8...... Running MUCH better out of the hole....

 

[cloudmaster_321]

How did it go? Mine are at 1 1/2 and it is sluggish on take off... going to 1 1/4 ......

Update... Went to 1 1/4 and it got worse.... Now at 1 5/8...... Running MUCH better out of the hole....

Mine is running pretty good out of the hole on the 1 1/2 out on the low speed. Though, my mid range is rich. Top rpms are at 6,650 currently; which i think is low. Should be closer to 6,800 -7,000 i believe. I'm currently out 3/8 on the high speed needle pto, and 1/4 on the mag high speed needle. I think she is running a bit fat on top, i'm considering going back to 1/2 turn out on the pto, and 0 on the mag and trying again with the new low speed settings. I know they shouldn't overlap, but, eh...........