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Old 12-26-2009, 01:25 PM
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CasualGourmet CasualGourmet is offline
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MC2100 Problems

I hope someone can help me out.....I rebuilt the carb and I did the the adjustment for the float and now it runs like crap. It is backfiring through the carb, put another carb on, it idles for a minute or two the dies try to push on the accelerator and it runs real rough and dies. I am at wit end because I cannot find anyone around here that knows carbs. Thank you!
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Old 12-26-2009, 02:45 PM
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See if you missed anything - HERE
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Old 12-26-2009, 03:15 PM
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Quote:
Originally Posted by brad_fsj10
See if you missed anything - HERE

Well I did everything right but the back firing through the carb is where I am concerned.
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Old 12-26-2009, 03:39 PM
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Two things cause backfiring through the carburetor, timing and a lean condition. If you didn't mess with the timing then carburetion is suspected. As you just rebuilt yours - probable.

Did you reconnect the accellerator pump lever; adjust it at all... unnecessarily? When the engine is off, can you see a clear double shot of gas spraying into the carb throats when you blip the throttle lever? If yes...

Did you adjust the idle mixtures too lean? Shouldn't have that big of an effect but if the set screw are still bottomed out it won't draw any gas through the venturies at tip-in. If 1.5 to 2.5 turns out each...

Did you set the float correctly? Too low will starve the engine after tip-in.
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79 J20
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D44/D60/3.31s
past rigs -
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80 J10
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Old 12-26-2009, 05:16 PM
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Quote:
Originally Posted by brad_fsj10
Two things cause backfiring through the carburetor, timing and a lean condition. If you didn't mess with the timing then carburetion is suspected. As you just rebuilt yours - probable.

Did you reconnect the accellerator pump lever; adjust it at all... unnecessarily? When the engine is off, can you see a clear double shot of gas spraying into the carb throats when you blip the throttle lever? If yes...

Did you adjust the idle mixtures too lean? Shouldn't have that big of an effect but if the set screw are still bottomed out it won't draw any gas through the venturies at tip-in. If 1.5 to 2.5 turns out each...

Did you set the float correctly? Too low will starve the engine after tip-in.

I have a feeling that the timing is going to be the first suspect. I have a professionally rebuilt MC2100. What is the fuel outlet at the top of the float bowl...MC2150? Will it make a difference if I use a MC2150 in place of the MC2100 I took off due the problems I was having. I rebuilt the MC2100 twice and had a local dealership "calibrate" the carb but it they said to just buy a new one and got it back and it runs worse than when I took it there. The new carb I bought is a MC2100 D...is that going to make a difference?. Thank you for the link on the carb!!
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Old 12-26-2009, 05:23 PM
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CHICOWAGGY CHICOWAGGY is offline
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Location: Chico, CA
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Quote:
Originally Posted by CasualGourmet
I have a feeling that the timing is going to be the first suspect. I have a professionally rebuilt MC2100. What is the fuel outlet at the top of the float bowl...MC2150? Will it make a difference if I use a MC2150 in place of the MC2100 I took off due the problems I was having. I rebuilt the MC2100 twice and had a local dealership "calibrate" the carb but it they said to just buy a new one and got it back and it runs worse than when I took it there. The new carb I bought is a MC2100 D...is that going to make a difference?. Thank you for the link on the carb!!

Its the bowl vent, keeps the fumes from building up. It goes to the charcoal canister.
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