GSX 98 runs lean around 3/8 throttle

[mikidymac]

That is what I have always seen. No connections between the oil and fuel tank.

 

[Matslor]

After tightening the hose clamp the fuel leak stopped.
Now i have a little : "psssh" from the gastank when opening the gascap. So the tank is pressurised now i assume? Please correct me if im wrong.
Yesterday i noticed gas leaking from the valve at the front of the seat.

 

[1of500]

You need to replace both of the check valves in the fuel system the one under the seat you have pictured and the one under the rub rail

 

[Matslor]

Ordered new check valves.
Tried to pressurise the fuel system through the fuel return line. Found a tiny airleak from the water seperator

 

[Mickirig1]

Now it should run like full throttle.

 

[Matslor]

Got the new checkvalve yesterday. Bypassed the water seperator filter so i could test the jetski.

Was running great when engine was cold, but after a few minutes the problem was still there..

Must say im starting to loose the motivation.

When i took it out of the water and ran it with the garden hose, it seems to hesitate when i give full throttle. Have not been like this before. Previous experience with 2-stroke engine is that they are very responsive

Adding 2 videos for you guys to see.
I really appreciate all the help you guys have given me, would like more

 

[ryffish]

Your still having lean issues with that ski . I have a solution sell it as is and take proceeds and buy another

 

[Chester]

Some things you haven't mentioned. What are the mixture screws set at? Is the stock air box still on it? What jets are installed? A leaking fuel tank vent valve will not affect how the engine runs at all.

Chester

 

[Matslor]

Mixture screw is set at : Low Speed – 1 1/2 +/- 1/4
High Speed – 0

Stock air box is still on.

The carbs are stock, didnt check what valves was installed.
Previous owner told me that the ski worked fine until last summer and have not changed the jets.

 

[ryffish]

I also told you a hairline crack in your block will cause your engine to lean out

 

[Matslor]

I also told you a hairline crack in your block will cause your engine to lean out

Yes i remember.. considering pulling out the engine to inspect it.

 

[Matslor]

https://m.youtube.com/watch?v=4UePryxik1k

Took a video last time i drove it.

 

[ryffish]

It sure does act like it's starving for gas

 

[ryffish]

your carburetor might be turning into a carbitraitor. Meaning it's not working right .

 

[ryffish]

I saw your video that's exactly how mine was running . And it was fuel valve the one that you turn on and off and on reserve. But you already eliminated that problem right

 

[Mickirig1]

Might consider buying a used carb and install. I did it with my problem child Ski 13. It fixed the problem. CoastieJoe can tell you. I went over and over Ski 13. Are you sure it is a carb / fuel problem? Could need spark plug wires trimmed or have a connection problem somewhere. Was carb cleaned right and all wear parts replaced? JETS REPLACED? Pulled the jets and cleaned passages? Might need the, not normally replaced gaskets, replaced. Running the same after warm, kinda says it's one of these issues.

 

[Chester]

Try setting the low speed screws to 1 3/4 turns.

Chester

 

[Chester]

Mixture screw is set at : Low Speed – 1 1/2 +/- 1/4...

Check to see exactly what they are at.

Chester

 

[Matslor]

I saw your video that's exactly how mine was running . And it was fuel valve the one that you turn on and off and on reserve. But you already eliminated that problem right

Yes i assume! Pulled it out and cleaned it with diesel and then used compressed air. But the valve is "sealed" so i couldnt inspect the inside of it.
Can i try to bypass that too ?

 

[Matslor]

Try setting the low speed screws to 1 3/4 turns.

Chester

Tried that too. Set all the adjuster screws to stock/what manual told me. Tried to adjust the low speed a littlebit after driving with stock setting.
About 1/8 turn out, but no response from engine.
Gonna adjust it to accurate 1 3/4 next time i try it.

 

[Matslor]

Might consider buying a used carb and install. I did it with my problem child Ski 13. It fixed the problem. CoastieJoe can tell you. I went over and over Ski 13. Are you sure it is a carb / fuel problem? Could need spark plug wires trimmed or have a connection problem somewhere. Was carb cleaned right and all wear parts replaced? JETS REPLACED? Pulled the jets and cleaned passages? Might need the, not normally replaced gaskets, replaced. Running the same after warm, kinda says it's one of these issues.

I am considering taking a pressure test on the engine.
The only thing i have checked regarding ignition is the spark. It was great.

Yes i bought i carb kit from mikuni and changed all the wear parts.
Jets are not replaced! Should i change to get a higher popoff? The popoff is on minimum regarding the manual.

Cleaned the jets and seats.
Suspecting previous owner did the same job. Everything looked new. (Gasket, 100% clean fuel filter etc)

 

[nitr0genics]

Just out of curiosity, have you tried using the reserve setting on the selector valve and I don't mean because the normal valve on the selector may be blocked but the actual feed from the baffle in the tank could be gunked up?

 

[Matslor]

Yeah forgot to mention that. Tried both on and res while driving, but no difference in engine response.

 

[1983]

Yes bypass the selector valve. I actually remove them on all my skis.

This could very well be your problem. The get clogged quite often.


Rob

Yes i assume! Pulled it out and cleaned it with diesel and then used compressed air. But the valve is "sealed" so i couldnt inspect the inside of it.
Can i try to bypass that too ?

 

[ryffish]

I told you fuel valve a month ago and all you did was clean it . That's not gonna work .