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Allisgrandson

Hard starting Carb

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Allisgrandson

I have a B12 that sat for a few years, and I just got it running. The problem is that I have to remove the air filter and use my palm to block all air inflow into to the carb to get it running. I've found that splashing some gas into the spark plug hole helps also.

Once it's running, it runs strong.

Any ideas?

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Allisgrandson

The Choke is the next thing I was going to check. As I looked through the threads here, I noticed a WD-40 test, where WD-40 is sprayed on the joints of the carb to listen to a change in engine pitch to check for air. I'll give it a whirl tomorrow. Thanks!

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Willy

Try holding the throttle closed when you crank it, I have a

B-10 that would crank all day and not start, hold the throttle

closed and it pops right off.

I don't know why but as long as it starts I can live with it.

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RonHatch

My B10 with a B&S is the same way. Throttle closed, full choke, at least a 1/4 tank of gas and it starts right up. It took me awhile to figure that one out. I'm thinking it's be because the carb is so low. ??

My Kohlers aren't like that at all.

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HubbardRA

Check your choke plate. Some carbs had a one-way valve in the choke plate to let a little air pull through when the choke was completely shut to prevent flooding. These tend to come loose and fall off the plate. Without that valve there is a hole in the plate that prevents it from completely shutting off the flow pulling a high vacuum when shut. The palm of a person's hand just does a complete closure a little farther down the inlet tube. I have pop-riveted a couple washers in the hole to prevent air leakage on a couple carbs and it seemed to work fine.

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Allisgrandson

HubbardRA, that's a good point to check. I'm going to swap a known good carb onto it and see if she pops of with that one. I have a couple of spares and a rebuild kit i'm going to try and get to this week.

If I dump gas into the plug hole, she fires right up which supports your too much air theory. It runs very strongly after a minute warm up, though I have seen fire out of the rotted out Nelson can muffler. Would a stuck valve give me this problem?

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HubbardRA

Fire out of a short pipe or rotted out muffler is not abnormal. Most of them will do this once they warm up. It is more noticeable after dark on on an overcast day. Seen this on my tractors many times. A good muffler or a longer pipe should stop the flame from being visible. The visible flame is not related to anything being wrong with the engine, just something wrong with the exhaust.

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Allisgrandson

HubbardRA,

I finally got around to taking my carbs apart and found that I am missing the relief valves on the choke plate. I do have one good choke plate. Which way does that valve go? I currently have it positioned so that it will release any pressure coming from the engine and totally restricts air from the filter if closed.

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