Afternoon all, follow-on and variant of previous post. (1994 GTX 657X). I have confirmed entire fuel system is free and flowing to the carbs and the pressure relief valve and check valve for the tank are ok. With intermittent stumbling or dying at high speed and now (last time I had the ski out only time its done it) hard to restart condition should I check settings on low/high speed screws and test on water or do the full pull of the carbs. Rebuilt last year with genuine Mikuni parts and ran well most of the summer. I had been running ethanol free but couldnt get it for the last few tanks of the season due to outages in the area. Should I look for obstructions down all the way to the jets then do a pop off leakdown test or as long as I don't mess with the needle and seat those aren't needed ? Thanks for the expertise.
657X carb test question
- Thread starter ezgoin92
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I pulled the entire fuel system out including the selector, everything is clear and air flows good through it with no debris Pulled the carbs and there was a little bit of debris in the rear filter. Did a full carb rebuild last night and popoff tests are in spec and within 2-3 psi of each other. went to put them back on tonight and i bumped the mag side oil line going from the pump to the cylinder and broke the brass tip off. looks like back to being dead (out) of the water. need to acquire a new elbow that attaches to the pump but wont get that within a day to take down to the lake for the weekend. Thanks for reaching out.
AKnarrowback
Well-Known Member
Did you check your Rotary Valve cover clearance? One condition of excessive clearance is hard starting that becomes even more difficult if the motor is warm.
High speed adjustment screw is turned in all the way and left there. If you spin it out it only richens the mixture, not sure what the low speed is.
You said it's a 94 gtx with a 657x? I believe the 94 only had a standard 657, the 95 gtx had the 657x. Double check the motor identification tag on the stator housing and the last two digits of the black hull tag riveted to the rh side on the back of the hull.
You are dead on in going back through the fuel system. Not many people would go to those lengths, but sometimes it needs to get done to eliminate all the possibilities.
Did you pressure test the fuel system? Air leaks can cause problems and burned motors.
Good catch on finding the small filter with material in it. Button everything up and see what happens. Run it with the same plugs you had in when the machine gave you trouble, if the problem still exists try swapping plugs for fun.
Just to cover another base, if the tuned pipe is a two piece unit double check the rubber hose clamp to make sure there isn't any separation and leaking. My 94 had a little heat damage to that hose section and caused the machine to fall in it's face.
Let us know what you find.
High speed adjustment screw is turned in all the way and left there. If you spin it out it only richens the mixture, not sure what the low speed is.
You said it's a 94 gtx with a 657x? I believe the 94 only had a standard 657, the 95 gtx had the 657x. Double check the motor identification tag on the stator housing and the last two digits of the black hull tag riveted to the rh side on the back of the hull.
You are dead on in going back through the fuel system. Not many people would go to those lengths, but sometimes it needs to get done to eliminate all the possibilities.
Did you pressure test the fuel system? Air leaks can cause problems and burned motors.
Good catch on finding the small filter with material in it. Button everything up and see what happens. Run it with the same plugs you had in when the machine gave you trouble, if the problem still exists try swapping plugs for fun.
Just to cover another base, if the tuned pipe is a two piece unit double check the rubber hose clamp to make sure there isn't any separation and leaking. My 94 had a little heat damage to that hose section and caused the machine to fall in it's face.
Let us know what you find.
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