1999 GTI wont go over 30mph, need help

[Coastiejoe]

You are sucking air somewhere. Pressurize the fuel line and find the leak. Common for the O-ring on the separater to fail and suck air.

 

[Mekanix]

See an occassional small bubble heading back for the tank... just ran it again on WOT and really looked at the lines. The small line that comes out of the bottom of the accel pump to the top of the carb is geeting airbubbles (like an aerator at WOT). Is this normal?

Huh ? So you changed the lines going to and from the accell pump to clear lines ?

On the output of the pump that's fine and you will see some bubbles if the check valve in the sprayer lets gas dribble out while the engine is vibrating. It will fill up again when you hit the throttle again.

However for the other line going to the pump from the metering chamber there is a small restrictor in that line!

Looks like a small pilot jet.

The accell pump is supposed to be like a check valve and only allow fuel to go one way but if the pump is bad and you changed the line that could cause air to get sucked backwards and into the metering chamber. And if you had the old lines in there, that restrictor would have limited the amount of air being sucked backwards. So the machine might have and a problem with the pump and you wouldn't have known it until you changed the lines and discovered this. (I did the same thing the first time changing lines on my GS and discovered Oh yeah there is a restrictor in there. Probably going to need that )

So once you suck all the gas out of the chamber and there is air in there instead, that means you don't have enough suction to pull the diaphram down and push on the inlet needle to bring more fuel in.

But there might be enough suction to just work good in the mid range.


I think your getting to the point where you'll have to start checking the carb itself for leaks



Also like Coastie said that square O-ring on the cup of the water seperator is a common problem that causes air leaks and it behaves like a 3/4 / WOT hesitation but behaves ok on low end.

 

[ironmike4134]

Went to the Lake and it ran great. Was hitting nearly 50 at WOT. Still want to play around with some adjustments but problem solved. The main solution, fix the exhaust leak (Rubber piece between the tuned pipe (upper half) and the lower exhaust pipe. 2nd fix item... not sure if it mattered... tightened up the fuel filter (dont think this was the problem as I was not getting big air bubbles and I was running rich.. Thank you to everyone who replied on this Thread. Learned a lot of new things about jet skis!

 

[ironmike4134]

also forgot, did the lithium thing on the square o-ring for the water separator.