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Discussion Starter #1
Hello gents need help with a 1992 traiboss 240 4x4 i did a rebuild on carb it was leaking so got a kit on Amazon wow what a mistake most parts didn't fit right . So i cleaned all really good and used some from carb . It runs starts up runs ok but i can't seem to get from Backfriring when you let off the throttle ? I have played around with this thing for days fiddling with air screw took i it apart and cleaned again to make sure all is good i am lost here . Please if any here know some thing also any Guys on here from NJ
Thanks Chuck:eek:
 

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Discussion Starter #6
another quick question are those vacuum lines or breather lines coming off carb ?
mine has a tee and a check valve on one side and one line goes to tranny?
 

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Discussion Starter #7
well it only does it after a long hold on throttle small pulls are ok and some times out front pipe but have ahd a few out mid
 

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The lines on the carb are fuel, vent and drain - the one on top is the vent and it may tee to the drain line - the check valve is in the drain line - the drain line may not be teed to the vent line in which case it simply drops down behind the engine to allow any fuel spill over to escape away from the engine and other parts - the transmission vent may be teed to the carb vent line in which case a line off the tee will go above the carb and the open end will be tied to the frame under the fuel tank. If the vent line is not open ended somewhere the carb may not fill with fuel properly and may cause run-ability issues. If the drain line is connected to the transmission, it will let any fuel spillage drain into the transmission contaminating the oil.

If it only backfires after a long hard run, I would guess the main jet is too big causing the engine to technically flood with fuel which is expelled into the hot exhaust and when the throttle is closed, the excess fuel ignites in the exhaust. Or, it is excessively lean at idle or the idle speed needs to be increased - either way, rejetting the carb or adjusting the idle up will help alleviate the backfiring.
 

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Discussion Starter #9
ok so the one by the choke is a vent?
the one on other side of carb would be a vent?
one on bottom of carb i know is overflow
so does the tranny line need to be hooked to the ones on carb and do i really need the check valve as for back fire if you plip the throttle it's fine but if you hold opne as to raise the speed of the engine and then let of fast that's when you get back fire sorry i haven't explained my self to well
 

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The carb could have one or two vents - I'd need a pic to point them out

The drain has a check valve to prevent water from backing into the carb during water crossings
 

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The brass nipple and the black plastic nipple are both vents - connect them together with a tee and run the hose up high on the frame under the tank or seat an it will be fine
 

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Discussion Starter #14
good morning say i have another quick question you might be able to answer?
I have a 2000 325 magnum 4x4 i use for plowing we got some snow last night and took atv out today.Run fine but after i put back in shed shut it down truned off gas and went to finish with shovel i went back in shed and smelled gas didn't see anything leaking ?
Got any ideas ?
thank you
 

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A hot engine will heat the carb and fuel will evaporate out the float bowl vents to the atmosphere - in a closed shed the fumes may be detectable - as long as no leak was found, I would pass it off as that, but keep an eye on things - it might be a leaky petcock, fuel pump, fuel tank or line.

An extreme example of a possibility; (this happened to a friend of mine and he got all hyper about it) he had been plowing snow, got done and filled the fuel tank right to the brim (actually spilled a small amount of fuel putting the cap back on the tank - he rode it up and down the 200 foot drive way an couple times to 'evaporate' the spillage before putting it away in his heated garage. The next morning he went into the garage and smelled gas - he found a small puddle of fuel under the 4 wheeler - he immediately opened the garage doors and pushed the quad outside - left the doors open and the quad out for about 2 hours so 'all the gas would disperse and prevent his house from blowing up' - like I said he was hyper. He called me and I went over to investigate. We started the quad up and moved it back into the garage. I started checking it for leaks - found none, but there was about a half of a drop of fuel hanging on the fuel tank vent line. I figured it was just spillage (overflow) from moving the machine. I checked the fuel tank and it was about 1/2 inch below the rim of the opening. My friend said it should be full - he just filled it before putting it away. I said "Well there's the problem - you are not supposed to fill the tank that full - you are supposed to leave about 1/2 inch of air below the bottom of the filler. With the tank completely full, as the fuel warms in the garage, it expands and can be forced out of the tank vent line. While we were discussing things I noticed the fuel level had risen about 1/4 inch. I put the cap back on the tank and while we were having a cold one, i noticed fuel dripping on the floor. Sure enough it was coming out of the tank vent line. I removed the gas cap and lo and behold, the fuel was nearly to the top of the filler - we left the cap off and about 20 minutes later there were lots of drips of fuel and the garage was starting to smell of gas. The fuel was now overflowing out of the filler neck and running down the sides of the tank. I removed the fuel line from the petcock, attached a length of hose and drained about a pint of fuel out of the tank. Put it all back together and said bye. He called me the next day and said it stopped dripping, but the fuel in the tank was about a 1/2 inch higher than it was after I drained some out. I just said fuel expands as it gets warm - either keep it cold, don't put so much in it or use it for 15 to 20 minutes after filling it. He hasn't had the same problem since then.
 

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Discussion Starter #16
Wow That's mouth full well put thank you i am sure you helped a lot of people that will read this and take notice this
have a good day:):):)
 
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