Mtd wont prime!!! (Headache!!) - Snowblower Forum : Snow Blower Forums
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post #1 of 9 Old 12-22-2015, 03:35 AM Thread Starter
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Mtd wont prime!!! (Headache!!)

I have a very common mtd 4.5HP snowblowet. This **** thing has me banging my head against the wall. I have thoroughly cleaned the entire float bowl and plastic emolsion tube, still no luck. When i hit the primer button all i get is a hiss of air coming from this little black hole on the side of the carb. Any help would be appreciated, as im tired of fixing my wall.

Yours truly, chimpboy
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post #2 of 9 Old 12-22-2015, 03:43 AM
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Did you check all of the fuel line? Got to be sucking air someplace.

Just went through that on my chainsaw, ended up replacing 'em all.

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post #3 of 9 Old 12-22-2015, 07:43 AM
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If you're sure you don't have any leaks in the primer line, check to see if you notice fine fuel bubbles around the float bowl gasket. If any air passes the rubber gasket, the primer bulb will only push air. I started a thread "leaking carb bowl gasket". Lots of good advice from members.
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post #4 of 9 Old 12-22-2015, 09:41 AM
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to the forum Chimpboy

The primer bulb pushes air to the carb through a vacuum hose that should be connected to a nipple on the carb.
The air pushes on the fuel in the carb and is supposed to force some raw fuel up into the throat of the carb.

Is the line connected to the nipple on the carb ??
Can you post a photo showing the "black hole" on the side of the carb you say air is coming out of ??

Leaking carb bowl gasket :

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Last edited by Kiss4aFrog; 12-22-2015 at 09:44 AM.
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post #5 of 9 Old 12-22-2015, 09:44 AM
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Check the bulb itself very carefully. It may have a hairline crack in it.

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post #6 of 9 Old 12-22-2015, 09:53 AM
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Gotta have an air leak somewhere. Been there, done that.

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post #7 of 9 Old 12-23-2015, 09:36 AM
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Recently I worked on a Go-kart engine where the air filter housing screw went into a passage and if the screw wasn't in, it wouldn't prime.

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post #8 of 9 Old 12-23-2015, 11:03 AM
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Another thought - if somebody has ever used gas with etynol blend is will soften the hose/rubber tubes and parts and they will leak. try nipping the end off the primer line (carb side) and stick it back on (should be snug). Try to avoid the blended fuels if you can......

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post #9 of 9 Old 12-23-2015, 12:44 PM
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I am guessing the hole you are talking about is the vent hole on the left side of the carb. Pushing the primer should lightly pressurize the bowl and push fuel through the emulsion tube and into the carb throat. I would say you still have a blockage in the bowl nut passages or emulsion tube if the air is coming out the vent.

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