1994 Sea-Doo GTS missing top half of throttle

[jmurph]

My seadoo gts (587) sounds like it is not exceeding approximately 3000 rpm. It sounds like a limiting sound rather than bogging. Occasionally It blips and has correct acceleration/power for about 1 second. The engine does not die even when throttle is pulled all the way, and it starts and idles perfectly. I just went through and rebuilt carb, replaced fuel lines and filters. Pop off pressure tested at 25psi after I had to trim spring slightly. Curious where I should look too next.

 

[hingstin]

Do these models have the throttle -ignition control, like the 951.?
is there two leads out from throttle/oil cable?
it? it can be that throttle cable is out of adjustment, but it should be reqognized in 75-80 % of throttle "use"...

 

[WaterChampion]

Maybe run it in that state for a bit and pull key and check plug condition? Rich? Failing ignition coil?

 

[mikidymac]

My seadoo gts (587) sounds like it is not exceeding approximately 3000 rpm. It sounds like a limiting sound rather than bogging. Occasionally It blips and has correct acceleration/power for about 1 second. The engine does not die even when throttle is pulled all the way, and it starts and idles perfectly. I just went through and rebuilt carb, replaced fuel lines and filters. Pop off pressure tested at 25psi after I had to trim spring slightly. Curious where I should look too next.

There is one of your issues, you never cut the springs.

You need to be running genuine Mikuni parts including the 2.0 needle and seat and a 115 gram spring. Your pop-off should be 32 psi.

 

[jmurph]

Thank you all for your help, today I was able to confirm that opening the fuel lid and relieving the pressure allows it to run with full rpm for about 15 min. I assume that’s how long it takes to build a vacuum. I will run through the relief valves/lines again, but does anybody have other ideas if they’re not clogged? Also there’s one valve up top in the dry storage and one down lower. Which does what? Thanks!

 

[burtshaver2021]

The valve up high allows air to enter the tank only, and the valve down low, usually under the rub rail allows excess pressure in the fuel tank to escape only

 

[jmurph]

Thank you all for your help, today I was able to confirm that opening the fuel lid and relieving the pressure allows it to run with full rpm for about 15 min. I assume that’s how long it takes to build a vacuum. I will run through the relief valves/lines again, but does anybody have other ideas if they’re not clogged? Also there’s one valve up top in the dry storage and one down lower. Which does what? Thanks!

Final Update: To my surprise replacing top hoses, spraying carb clean through the valve, and half a turn out on the high screw seems to have solved it. Besides that now it seems to idle/start harder. Might just be a low speed adjustment. I saw many saying that the fuel tank vents would never cause issues running but I seem to have disapproved that. Thanks all!