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Post by jonasbriggs on Dec 16, 2017 19:23:46 GMT -5
hello. I have tao tao 49cc 139qmb engine with 100cc big bore kit. my problem is my carb keeps flooding. I checked timing, engine compression tightened and retightened. I have plenty spare parts. I've tried 3 different carburators and all do same thing. keep flooding. on air hose I see gas dripping out. what can possibly make all 3 carbs to keep flooding? I've done 5 big bores already and pretty experienced but this issue I cannot seem to be able to solve. I get spark and air suction AND gas. I have advanced coil did and exhaust as well as rebuilt air box for better flow. it's first time this happened. any help is greatly appreciated
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Post by gsx600racer on Dec 16, 2017 20:56:22 GMT -5
The diaphragm on fuel tank petcock is broken and the petcock needs to be replaced.
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Post by jackrides on Dec 16, 2017 22:05:41 GMT -5
Your oil is probably diluted with gas. Change it and measure how much comes out. Till you find the problem, gently clamp the fuel and vacuum line closed. If it is over 28-30 (+-) oz, don't drive it till problem is fixed.
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Post by jonasbriggs on Dec 16, 2017 23:07:34 GMT -5
diaphram on petcock is good. just checked. oil is new cause i just installed 100cc bbk on the engine. timing is good. tried changing cdi no go. changed 3 carbs no go. any other ideas?
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Post by gsx600racer on Dec 17, 2017 4:35:23 GMT -5
Is it flooding when running or flooding when just sitting?
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Post by jonasbriggs on Dec 17, 2017 23:00:10 GMT -5
flooding when I try to start it
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Post by jonasbriggs on Dec 17, 2017 23:03:54 GMT -5
I empty gas out of carb then when I try starting...it fills it up and then floods the air box
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Post by greginisn on Dec 18, 2017 4:49:36 GMT -5
It’s hard to believe that all 3 carbs have a lazy float valve.
With just a carb full of fuel and the tank disconnected will it start and run OK? Assuming it was running well before the bbk your electronics should be OK but do check your connections if no spark.
Are your fuel connections connected correctly? You aren’t sucking fuel into a vacuum port? I realize you have experience in these things and I might be asking dumb questions but sometimes you just gotta step back a bit and rethink it all.
Good luck, Greg
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Post by gsx600racer on Dec 18, 2017 6:00:51 GMT -5
I agree with greginisn, I find it odd that all 3 carbs are bad. That is why I suggested the fuel petcock being bad. With both hoses from the fuel tank(fuel & vacuum)disconnected, Does fuel flow out of either hose ? A bad petcock would cause the engine to flood(sitting/starting/running)
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Post by jonasbriggs on Dec 18, 2017 18:18:18 GMT -5
when both hoses disconnected fuel runs out of only one hose. the one that connects to carb. the other one is not leaking anything. this is normal I believe. tomorrow I will try to rebuild the engine once more....but this is 6th time me doing so... it's painfully just to sit 3 hours a day trying to figure out the issue.
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Post by jonasbriggs on Dec 18, 2017 18:24:03 GMT -5
greginisn I get spark air and gas. it just overfills my carb. btv, as soon as I rebuilted the engine prior to asking for advice it did start.. I turned off engine, put on my exaust...then.. that's when carb problem started. I disconnected e xaust and tried and ever since would turn over but my rpm meter is stuck at one won't start. seals are good im sure cause they're new.. so is compression I believe.
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Post by jonasbriggs on Dec 18, 2017 18:26:26 GMT -5
maybe the gas isn't going into engine... cause the hole which carb sits on feels dry. if that's my problem how would I fix that? or even test it?
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Post by greginisn on Dec 18, 2017 22:19:35 GMT -5
Jonas, I just can't shake the idea that the carb is hooked up wrong. That some hose is misplaced. I don't know there is a one size fits all carb foto but maybe this can help. Good luck, Greg
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Post by gsx600racer on Dec 19, 2017 1:18:35 GMT -5
When you say
Are you applying a vacuum to the other hose is when you say the above statement ?
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Post by jonasbriggs on Dec 19, 2017 12:19:53 GMT -5
first is gas second is vacuum line. vacuum line is dry the gas line runs a bit of gas then stops leaking out. the problem may be in engine itself. is there any part of engine not carb that may make carb flood?
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