GT90 Carburetor Help

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Rampage9086

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And to add to that if you do have the fuel line hooked up right and the overflow keeps pouring fuel then your floats need to be adjusted so that it shuts the main jet and will stop overflowing hope that helps
 


gary55

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And to add to that if you do have the fuel line hooked up right and the overflow keeps pouring fuel then your floats need to be adjusted so that it shuts the main jet and will stop overflowing hope that helps
Well the post was from Aug. of 2017, so he probably has solved the problem by now. Sure is good to know that the float shuts the main jet though. That must be a very unique carb.
 

Phabbits

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Well the post was from Aug. of 2017, so he probably has solved the problem by now. Sure is good to know that the float shuts the main jet though. That must be a very unique carb.
Ahh Gary, I wish! Unfortunately the bike project has kind of been moved to the back burner as work and school have ramped up. I am however expecting this semester to be easier and I should have time to get back on it!

The problem of the constant leakage was most likely due to the angle that the carburetor had to be mounted at, and for the most part I have gotten it level, so there is less leaking now. I will look into my float height however, if that does not fix the problem.

But as it seems this bike project goes, as one problem is remedied another one shows up. The problem now is that it dies shortly after starting if not being constantly revved. I had my uncle who has had many years of experience with gas engines look at it, and he believes that the motor is simply not getting enough fuel.

I have very little experience with carburetors, just this project, and not really sure how to check the jets and float. The fuel line and filter is clear, and I see them both constantly filled with fuel. The what I know now as the nitrous port on the carb, thanks Rampage, is not capped and just had a disconnected line running from it, could that affect things?

Any help on how to troubleshoot fuel on this motor appreciated! Thank-you for your replies!! Maybe I should start a newer thread for this new problem...
 

Street Ryderz

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Ahh Gary, I wish! Unfortunately the bike project has kind of been moved to the back burner as work and school have ramped up. I am however expecting this semester to be easier and I should have time to get back on it!

The problem of the constant leakage was most likely due to the angle that the carburetor had to be mounted at, and for the most part I have gotten it level, so there is less leaking now. I will look into my float height however, if that does not fix the problem.

But as it seems this bike project goes, as one problem is remedied another one shows up. The problem now is that it dies shortly after starting if not being constantly revved. I had my uncle who has had many years of experience with gas engines look at it, and he believes that the motor is simply not getting enough fuel.

I have very little experience with carburetors, just this project, and not really sure how to check the jets and float. The fuel line and filter is clear, and I see them both constantly filled with fuel. The what I know now as the nitrous port on the carb, thanks Rampage, is not capped and just had a disconnected line running from it, could that affect things?

Any help on how to troubleshoot fuel on this motor appreciated! Thank-you for your replies!! Maybe I should start a newer thread for this new problem...
enlarge the pilot jet and raise the needle to keep it running at idle properly,the line rampage referred to is NOT a nitrous port it's for oil injection and yes it should be capped off.The float should be adjusted to stop overflow and it shuts off the fuel inlet not the main jet,the main jet usually needs to be larger than what came stock to work properly.
 

gary55

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Thank god. I have absolutely no experience with this particular carb so was wiating for someone to step in with some experienced advice. Thought it might be a over flow or by it's position a oil injection, also generally reed engines need larger jetting, but not knowing this carb kept my mouth shut. What I do know is I never seen a nitrous port on a stock carb. Never seen a boost bottle connection on a carb. That's a intake thing. Never seen a carb that has it's jet shut off by the float. New I smelled bullsh*t.
 

Phabbits

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enlarge the pilot jet and raise the needle to keep it running at idle properly,the line rampage referred to is NOT a nitrous port it's for oil injection and yes it should be capped off.The float should be adjusted to stop overflow and it shuts off the fuel inlet not the main jet,the main jet usually needs to be larger than what came stock to work properly.
Hey Street Ryderz, thanks for the help! I noticed in your reply you mentioned to enlarge the pilot jet, and also that the main jet usually needs to be larger as well. Should I buy new jets, or is it possible to drill them out?

Also do you know of any good sources where I can learn more about carb adjusting, like raising the needle? I have not had too much luck just searching the internet.

Thanks!
 

Street Ryderz

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Hey Street Ryderz, thanks for the help! I noticed in your reply you mentioned to enlarge the pilot jet, and also that the main jet usually needs to be larger as well. Should I buy new jets, or is it possible to drill them out?

Also do you know of any good sources where I can learn more about carb adjusting, like raising the needle? I have not had too much luck just searching the internet.

Thanks!
It is possible to drill out the jet's with a micro bit set numbered 61-80 and allows for slight increments over swapping jets but that's the most common choice.Getting the idle right first off makes the rest far easier,when the pilot jet size is correct the air screw should be between 1-2 turns out so like ideally 1 and a 1/2 turns and this is for every carb.From there the transition between the pilot and needle can be fine tuned with the needle position and the main you want to go up until it just starts to four stroke or not run cleanly at wot it's mostly listening to how it's running through out the range and after you've done it a couple times it gets much easier.
 

Street Ryderz

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Oct 14, 2016
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Which carb is this. Recently arrived 66cc. Best ways to tune for max performance help?
I've not messed with that setup yet,but a carb is a carb set it up like any other and go through the steps.The biggest question here I would think is how well does that reed block work and does it seal well? I have not really looked at that one other than pictures online and they don't tell much of a story! Keep us posted as to how this works out.
 
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