1998 Sea Doo GTX LTD 951 Run Away//Low Running RPM

[dylanthec]

Hi everyone, kinda new here and to the PWC field in general, but more familiar with ATVs, anyway, here's my issue(s);

Picked up a 1998 seadoo gtx ltd so far I have;
1) swapped a known running motor (on land) out of a different 1998 seadoo GTX LTD
2) cleaned but not rebuilt the carbs
3) replaced the fuel lines on the carbs (1/8ID for smaller lines 1/4ID for larger)
4) Taken compression (both near 130psi)
5) rebuilt jet pump
6) made sure premium (93) gas and sea foam were in tank
7) inspected RAVE, appear to be in good shape
8) ensured no exhaust leaks
9) tried different gas cap seal
10) all reed petals present with scope camera inspection
11) oil pump is running a tad rich

ISSUES
as of 6/22/23
-will not hit powerband in water MAX RPM 4500
-runs away really bad on the trailer (basically had to choke off 100% of air to prevent explosion)

Sorry for the long post been trying to get this thing running forever and ive stretched my abilities VERY far
thanks everyone

 

[WhiskeyD]

Fuel lines are 5/16" ID in and 1/4" ID return. Carbs should be rebuilt with OEM mikuni parts and pressure tested afterwards. Cleaning them and reusing the old orings and gaskets is just asking for problems. The engine is running away because its lean. Either air leak in block, air leak at/below carbs, or you are starving it of fuel.

 

[dylanthec]

Fuel lines are 5/16" ID in and 1/4" OD return. Carbs should be rebuilt with OEM mikuni parts and pressure tested afterwards. Cleaning them and reusing the old orings and gaskets is just asking for problems. The engine is running away because its lean. Either air leak in block, air leak at/below carbs, or you are starving it of fuel.

Gotcha, we did notice after the first post that some of the lines (black) were old and cracked (could be pulling air straight into lines) near the fuel selector (the selector was also broken) as well, upon further inspection, the grey vent lines were full of something that looked and flowed like honey, our solution now is redoing all fuel lines and then testing that, if that does not solve our issue was gonna get back into the carbs
Thank you

 

[EdwinBland]

Fuel lines are 5/16" ID in and 1/4" ID return. Carbs should be rebuilt with OEM mikuni parts and pressure tested afterwards. Cleaning them and reusing the old orings and gaskets is just asking for problems. The engine is running away because its lean. Either air leak in block, air leak at/below carbs, or you are starving it of fuel.

Listen to WhiskeyD….

When I got my first ski I also tried to clean the carbs without rebuilding with all new mikuni parts and new gaskets….short story… the motor lost compression due to an air leak… It was a $1100 lesson… read the service manual and ask folks how to do leak tests on the carbs, fuel system and engine if still not sure.
You have to learn this stuff if you want to run the older 2stroke skis…. None of the shops will work on them in my area…