This machine has been sitting up in a barn for about 2 years, carb was all varnished up, I disassembled the carb & soaked it in my carburetor parts cleaner bucket, it cleaned up to look brand new. put the carb back on & put a gas tank on with fresh gas, it starts easy and runs great with the choke on, turn the choke off and it idles perfect but will not throtle up, it just smothers down and dies, can't even feather it to increase rpm, turn the choke back on and it will throtle up beautifully. I put a new fuel screw with new o ring in it, have repeatedly soaked it for days but no improvement. This carb is so clean inside and out it looks brand new. I hate to spend 400 bucks on a new one if not necessary. Anyone got any ideas?
Thanks for a reply kerbbirds, yeah I'm thinking something's still plugged up but I removed every part from this carb & soaked it in carb cleaner for days, blew it out good with compressed air, still same problem. I disassembled it again a couple nights ago, got it soaking now, I'll blow it out & reassemble it again tommorrow & see what happens.
The carb looks like it has some fuel cross channels molded into the body of it that you can't get to with a wire or air pressure, may just need to keep cleaning it this way till something gives.
If you cant get the straw from a carb spray can into those passages and blow them out to be sure, maybe you can find a local shop with an ultrasonic carb cleaner, that breaks up the crud in all the little passages and makes it easier to blow it out.
I agree with checking the pilot jet, but if that were plugged, it would not idle at all, it controls the fuel circuit from idle to about 1/4 throttle. What type of carb do you have? is it a slide type carb, (lifted by cable) butterfly carb, or CV carb? ( slide is lifted by diaphram on top, depending on engine vacuum)
CV carbs will not rev if the diaphram is pinched, torn, or has a tiny hole in it, slide carbs will have throttle problems if the main jet or emulsion tube is gummed up, so make sure what type carb you have and check out the fuel passages for any obstructions.
It's a CV carb but the diaphram is perfect, it lifts up when revving the engine with the choke on.
I'm wondering if having the breather assembly removed would have any effect on it, (there are no vacuum lines to have anything to do with that)
I had the same problem with my 2004 250 AC, after I rebuilt the carb, same running characteristics, etc. . . It turned out I had put the diaphragm for the choke in upside down or backwards. Might want to check this out.
PROBLEM SOLVED!!! I had never removed the main jet from the nozzel, just cleaned and reassembled, I decided to check the numbers on the jets and after close inspection I realized some ya-hoo has had this carb apart before me and swapped places with the main jet and the pilot jet, (they are exactly the same size, shape & thread size, only difference is the drill hole size) After getting the jets in the proper places there is not a brand new one that runs any better than this machine. I feel stupid for not checking this sooner. Live & learn.
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