cub spit n sputter

jsfarmall · Jan 17, 2015

My cub starts easily and idles good. Ru s fine till about half throttle then above that starts spitting and sputtering. Can back the power down and clears up. Cleaned the carb. No change, pull choke no change. Ignition tune up?

old · Jan 17, 2015

Pull choke and no change as in no black smoke and engine still runs poorly?? If yes then maybe a vacuum leak. Yes maybe still check spark and make sure it is blue/white and jumps a 1/4 inch gap or more

erik dekeyser · Jan 17, 2015

Sounds like you dont have enough fuel coming from the tank. Try to take the glass bowl off and clean it out .I usually unscrew it from the tank and then clean the tank and make sure the opening is clear and there is a sceen in the fuel line also.

gene bender · Jan 18, 2015

I would put he timing lite on each cy at a time and watch for intermitten spark as the bushing in the dist could be worn i assume you have checked the tappets plug wires ect.

jsfarmall · Jan 18, 2015

Have checked the wires and stuff. They don't plug in very tightly but all the plugs have a golden brown look none black or wet. There is a bit of black smoke when I pull the choke but not much and the engine doesn't change a bit how it runs.

gene bender · Jan 18, 2015

Thats why i use a timing lite to make sure the fire is constant looking at them doesent prove they fire all the time thats why you go from wire o wire to make sure fire is there all the time at different rpms.

glennster · Jan 18, 2015

Just a thought, but did you check the air clear? Drop the cup and take a look see. Try taking the air cleaner pipeoff at the carb and see if it runs any better.

glennster · Jan 18, 2015

Opps should read air cleaner...

old · Jan 18, 2015

With it running pull each plug wire one at a time and notice if it changes the way it runs. As you pull them hold them close but not touching the plug and watch the spark jump across to the plug. If it runs better you have a plug or 2 that is fouled out even if they look good

jsfarmall · Jan 21, 2015

Have pulled the hose off the carb goin to the air cleaner and no change at all. I have noticed it will run good for the first little bit when its started then slowly starts messing up. I think I'm running out of fuel in the float bowl. I have a kit on the way. Needed it anyway. Will see how it works then.

mkirsch · Jan 21, 2015

You can rebuild the carburetor 100 times, but if you're not getting enough gas from the tank, it will still not run right.

Take the fuel line off the carburetor and run it into a catch container. Let a full gallon of fuel flow through. It should be a full consistent stream, no drips or trickles.

cub spit n sputter

jsfarmall

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old

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erik dekeyser

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gene bender

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jsfarmall

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gene bender

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glennster

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glennster

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old

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jsfarmall

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mkirsch

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