Hey guys, i need help. '92 750sx, just had carb rebuilt, great spark, engine cranks over very well, lots of fuel flowing from return port on carb, but motor will not fire. motor is all stock. I have not checked compression recently. Is it possible for timing to be off? looking for help and advice. Great forum!
SX/SXi/SXi Pro Great spark, has fuel, no start...
- Thread starter Warpman89
- Start date
- Location
- Arnold MO.
Is there fuel going into the carb throat? Compression would be my next guess. Did it run before the carb rebuild?
- Location
- Edmonton Alberta
I recently had sheared the woodruff key and even with the timing wayyyy out it would still backfire and sputter.
feartheride
feartheride
- Location
- St.Catharines,On.Canada
sounds like an issue with ur carbs
Mark44
Katie's Boss
- Location
- 100% one place
Time to pull the carbs apart.
mark44
mark44
BruceSki
Formerly Motoman25
- Location
- Long Island
you sure you have the lines hooked up to the carb correctly?
- Location
- Stouffville, Ontario
I don't know much about Kawi's or their carbs. I had a similar situation with my 38's on my 701. Turned out to be a small rip in the pulse line.
Good luck
Mike
Good luck
Mike
Magyar68
Really!!!
- Location
- Lewisville
If the wrong spring was installed when the Carbs were rebuilt would cause this, also if the Float arm was incorreclty adjusted..
A service manual might help with carbs and reeds. Their handy to have especially for torque specs
I need to do my carbs also but would prefer that someone who specializes in carbs only does them, that way I don't have to keep taking them off etc.. So as soon as I can afford it www.osbengineering.com
I need to do my carbs also but would prefer that someone who specializes in carbs only does them, that way I don't have to keep taking them off etc.. So as soon as I can afford it www.osbengineering.com
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After some tests, I found I have about 125 psi in each cylinder, is this ok? I did a vacuum test on the crankcase while cranking engine and pressure ranged from -5 psi to 5 psi. Is this enough for the carb diaphragm to operate. I am beginning to think I do not have enough vacuum in the crankcase because if I cover the throat of the carb as much possible and crank it, it will pop. Uncovered and the engine will not run and no fuel enters the throat of the carb. The next test I was advised to try was a true vacuum test on the crankcase by sealing the intake and exhaust manifold and put a vacuum on the case. I was told that if I can get negative pressure and air begins to leak back in, I may need crank seals.
Also, is the "T" of a fuel primer meant to be installed on the fuel supply line or return line?
Also, is the "T" of a fuel primer meant to be installed on the fuel supply line or return line?
- Location
- Cruising Around
You said you have fuel flowing through the return line so your fuel pump is pumping and recieving pulse from crankcase. You prime it and it fires. Take your carbs apart and clear all the ports, jets, high and low screw ports, N/S. check pop off is good and you should be A-OK. One small fleck of anything can block the low jet and ski wont run.
- Location
- Appleton, Wisconsin
Are your mixture screws turned all the way in? If so that is your problem. Should be roughly 3/4 out low speed. 1-1/4 out on high speed screw
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- Location
- Appleton, Wisconsin
750's also like reed stuffers, I dont know if your engine has them already or if they will fit with your carbon fiber reeds.
If you're worried about crankcase pressure, carbon reeds are harder to pull air/fuel through then whatever was in there. 125psi is low from memory. Grab a service manual there's one on here somewhere. And it sounds like your fuel is getting stuck inside the carbs. Do as wanderer1 said