Interesting jet sizes found in 96 GTX

[dr00andrew]

Finally got my pop-off in the correct psi range and now i took a look at the jet sizes. what is currently in there (how it was upon purchase) is a 130 main and an 87.5 pilot which is way off from what the factory settings are. My ski takes a 70 pilot and 142.5 main stock. I'm thinking I should just order the stock jet sizes and replace what is in there because they just seem way off from the stock settings. I am not asking for how instructions on how to jet/tune the carb, i just want someone else to chime in to my thought process. I figure, if that's the way it came from the factory, why would you put any other size in there? Thank you for your help

 

[etemplet]

I've been thinking of changing my jet sizes on my 96 GTX and my reason is I think I'm rich on the main but 130 from 142.5 is a lot less fuel. Wow !! I'd make sure the carbs are the correct ones for the ski. Seems like with those jet sizes something must be modified. How does the ski carburate?? Idle, transition, full throttle?

I'd do some checks and definitely consider going back to stock jets.

 

[GGuillot]

Finally got my pop-off in the correct psi range and now i took a look at the jet sizes. what is currently in there (how it was upon purchase) is a 130 main and an 87.5 pilot which is way off from what the factory settings are. My ski takes a 70 pilot and 142.5 main stock. I'm thinking I should just order the stock jet sizes and replace what is in there because they just seem way off from the stock settings. I am not asking for how instructions on how to jet/tune the carb, i just want someone else to chime in to my thought process. I figure, if that's the way it came from the factory, why would you put any other size in there? Thank you for your help

I've given up on trying to figure out what some people will do. You're doing what I'd do, put the factory jet sizes back in...

 

[dr00andrew]

I've been thinking of changing my jet sizes on my 96 GTX and my reason is I think I'm rich on the main but 130 from 142.5 is a lot less fuel. Wow !! I'd make sure the carbs are the correct ones for the ski. Seems like with those jet sizes something must be modified. How does the ski carburate?? Idle, transition, full throttle?

I'd do some checks and definitely consider going back to stock jets.

definitely on the rich side, especially from 0-1/3 throttle or so. Looked at the plugs as well and it is definitely running rich. my pop-off was low, and I corrected that but the pilot jet is allowing too much fuel, you can tell by how sluggish it is. Im just going back to stock jetting. Im really not sure why its been changed so much, but im going back to stock and seeing where that takes me

 

[etemplet]

Sounds like a good idea. I know a few people that try to correct engine and carburetor issues with changes in jetting. All that does is mask the problem or make it worse. Good Luck !! Post up the progress... inquiring minds and that. LOL

 

[dr00andrew]

For everyone interested, I am very pleased with the way my GTX runs. I started out with a 70 pilot and that was too lean, especially in the 2500-3000 rpm range. If i didnt feather the throttle it hesitated and occasionally stalled. I ordered some bigger jets and went with a 72.5 pilot and the low speed screws 1 3/4 out. My pop off is much closer to 40 than 35, so I think the slightly larger pilot helped my cause too. I may turn low speed screws in another 1/4 to 1/2 turn but it seems pretty damn good now.

Wow what a difference. can drive around in no wake zones all day long with no issues. WOT I get 6700-6800 RPMs depending on how glassy the water is and although I have not GPSed it with my phone,my info gauge is a hair over 50 mph WOT. High speed screws are 1/8 turn out each. I finally get to enjoy my ski now and keep up with basic maintenance. There are no issues with it, but should I replace my fuel selector switch now or just run it and do it over the winter?


For anyone with a 96-97 GTX 787 who stumbles on this thread at some point in the future with jetting issues, heres what works best for me

Needle/Seat Size: 1.5
Spring: Black 80 gram
Pop-off pressure: 39 psi
Pilot Jet: 72.5
Low Speed Adjuster 1 3/4 turns out
Main Jet: 142.5
High Speed Screw: 1/8 turn out

 

[etemplet]

Sure seems like you are giving that thing a lot of fuel on the low end but whatever works. Good Luck !!

 

[mikidymac]

Each ski is a little different but I have never seen a stock seadoo not run perfectly on the stock jetting assuming everything is working correctly. Typically you have an underlying issue if you have to change the jetting on a stock seadoo. Altitude can change this if you are high up though like Denver.

 

[dr00andrew]

Each ski is a little different but I have never seen a stock seadoo not run perfectly on the stock jetting assuming everything is working correctly. Typically you have an underlying issue if you have to change the jetting on a stock seadoo. Altitude can change this if you are high up though like Denver.

what are common underlying issues? the only thing i could think of is the fuel selector switch and the water/fuel separator. those are the only 2 fuel related things i didnt replace. i cant tell the condition of the bottom end but it does have good compression with 145psi in each cylinder. i will probably turn the low speed adjuster in another 1/2 turn. all the jetting is stock except 1 size up on the pilot and 1/2 turn out on the low speed adjuster

 

[mikidymac]

Fuel selectors go out all the time and the strainer are very common for air leaks also.
I would strongly suggest you replace the selector and strainer o-ring.

 

[dr00andrew]

i replaced them both and went back to stock settings. runs good, thank you for the advice. there was also a tear in the fuel line where it connects to the filter. that was sucking in some air