640 Fuel Delivery Issue

Doug (OH) · Apr 21, 2014

Hi everyone! Hope you"re all well. The winter gremlins attacked again. She started OK but I had to keep the choke almost full out to keep her running. Moving the throttle has little effect but linkage looks like it"s working OK. Also disonnected the air hose just to make sure she"s getting air. Carb is getting fuel, at least there"s fuel in bowl. Left it with a full, treated tank of gas over the winter. Clogged jet? Ethanol gas gunk? As always, thanks for the input. Doug

showcrop · Apr 22, 2014

Always start with the easy things. Remove the bowl and clean the screen. Next, remove the plug from the bottom of the carb and turn on the gas. Catch the gas and insure that it keeps running strong for thirty seconds. Plugging of the screen is very likely. I have cleaned a lot of crud out of tanks by siphoning with one of those $3.99 transfer siphons from the hardware store.

souNdguy · Apr 22, 2014

if spark is good, it either suddenly developed a vac leak.. or it has a fuel obstruction

Doug (OH) · Apr 23, 2014

Thanks guys, I'll check it out and get back in about a week. Have a great night! Doug

Doug (OH) · Apr 23, 2014

Hi Soundguy. Would you explain vac leak to me? I did loosen the gas cap, if that helps any. Thanks!

Doug (OH) · Apr 23, 2014

Thanks, Showcrop! I'll let you know what I find. Doug

showcrop · Apr 24, 2014

(quoted from post at 19:01:23 04/23/14) Hi Soundguy. Would you explain vac leak to me? I did loosen the gas cap, if that helps any. Thanks!

Sound guy is referring to the remote possibility of air being sucked in between carb and manifold or manifold and head.

souNdguy · Apr 24, 2014

showcrop got ya.

but yeah. vacume leak. vac leaks will lean out an otherwise good mix due to sucking extra air not thru the regular system, so fuel to air ratio is lean and imballanced.

fuel obstructions are more common than vac leaks IMHO..

640 Fuel Delivery Issue

Doug (OH)

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showcrop

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souNdguy

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Doug (OH)

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Doug (OH)

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Doug (OH)

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showcrop

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souNdguy

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