Wet plug situation after tweaking carb

[tnutcher]

Well as the title says, each time I try to get my carburetor jetted right and change something, when I put it back on and go to start the bike, it has never started first or second kick but more it floods and then the plug gets wet and air it out and either have to open the air screw 3+ turns or hold the throttle at WOT till it fires; upon firing it runs extremely groggy and spews gasoline out the tail pipe until it is all cleared out. :yell: After that it runs great and starts first or second kick if I jetted it correct. If I leave it to sit for a few weeks then it does a similar thing but not as bad.

Whats going on? Obviously I have too much fuel at startup - this happens with or without the choke on. Would it be my float level out of wack? The carb's been cleaned thoroughly each dissasembly and reassembly. . . The float needle seals off flow when the floats hit it but the only questionable part I have about the carb is the float setting. This is on my 91 rm250 but it has on a Mikuni VM roundslide carb the PO put on it. Jets are a 350 main - plug reading maybe a shade lean, i think last i put in is a 45 pilot and 3rd position on needle. It has an 8 plug in it and an fmf fatty pipe and silencer is the only aftermarket stuff on it.

Any input appriciated! As well as tips to set float height on this carb ect. Thank you very much
TNutcher :bang:

 

[tnutcher]

:uh: two days and no biters?? Anyone got any advise?? i'm lost on this one and don't know how far the float should be adjusted or if that's even the problem!
TNutcher

 

[tyler_43]

I'd check the reeds...
If the float level was off it would just cause gas to pour out of the carb overflow.

 

[tnutcher]

The reeds are fine, i checked them before my last ride. They're a dual stage reed pedal from boyseen - the semi-transparent ones. They help out loads down low for idling around and not stalling.

Then is it my starting technique if the float is off? Do you start is as normally would when the carb is dry? :bang:
Thanks,
TNutcher

 

[whenfoxforks-ruled]

http://www.dirtrider.net/forums3/showthread.php?t=92818, this is a start. That old, replace the float valve. I know, it appears to work fine, replace it and save a headache! Get some reference marks on your throttle and start at the bottom. 3 turns out on the air screw tells you the pilot is way off, but the float valve can cause a similar situation. Float height does not change by itself, putting the bowl on incorrectly or someone fiddled with it is another story. And finding the correct float height could be a problem. Does it have a drain screw in the bowl?

 

[tnutcher]

Alright I'll pick one up next time i'm at the store.

That thread was really interesting and insightful but not quite what I've been looking for. I did tweak the float height a bit from what it was when I got the bike but not sure if it was correctly set when I got it either. The tab was straight and I bent it to get a higher float height. I read that when holding the carb upside down the float height should be 17-19mm from gasket to bottom of the float itself. That seems awefully high. Right now its near 25mm i recall. Hell maybe try it and see. Worst that could happen is i'm still in the same boat.
TNutcher

 

[whenfoxforks-ruled]

If it is not high enough, it will be leaning out from not enough fuel. I was under the impression you are getting too much fuel? The plug will tell you. Work each circuit of the carb, check the plug on each circuit. The only real thing you can read on the plug is the main, but you can use it for reference, wet or dry, it can get you real close. Then ride it! The float height from a different carb has nothing to do with a different carb, they are different, and some get measured differently. I like when you are able to take a clear tube out of the bottom of the bowl and hold it up next to the carb, liquids seek its own level.

 

[tnutcher]

Well it isn't so much the running part but trying to get it to start. I can read the plug and figure out the lean or rich situation but the problem is when i try to get it to start, the thing FLOODS like fuel dripping out the exhaust port and plug dripping wet. I don't understand what i'm doing wrong or if the float is set wrong.

how high above the piolot jet opening should the fuel level be set to if I were to use the hose method as you say? I've thought about it but as a last resort. But I'm getting close to that. Is it a certain minimum say 5mm above opening or is it more 'just enough not to run dry WOT and loaded'?

Thanks
TNutcher

 

[whenfoxforks-ruled]

Start at 1mm below the bowl to carb seal. Good as place as any to start. It will show you if the float valve is shutting off also. Make sure the floats are sealed and installed correctly.

 

[tnutcher]

do this as it sits on the bike? or on a level surface? I assume the first because it tilts slightly. . . thanks
TNutcher

 

[whenfoxforks-ruled]

???? Well, in the bike.