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Could use a little assistance troubleshooting a lawnmower that won't start.

It's a Craftsman 6hp rear bagger, model# 917.388731. Picked it up several months ago from a used merchandise store, and they told me it came from an estate sale; it does not look like it had been used recently, and the gas tank was bone dry.

Here's what I've tried:

*When pulling the start cord the engine is not starting/running at all, not even chug-chug-die.

*Removed the carburetor and cleaned it out, including the bowl bolt with the main jet (thoroughly cleaned both the horiz & vert aspects of the jet) which was gummed up solid. Reassembled with existing gaskets.

*Replaced the rubber fuel line, which was severely cracked on the outside surface.

*Verified the handle control bar is working properly. When the bar is pressed down, the engine brake and grounding are relieved and when released, they are properly engaged.

*Replaced the spark plug (gapped new one at .030). With the plug uninstalled (grounded on the engine) and pulling the start cord it displayed a strong, consistent spark.

*Removed and vacuumed out the air filter. Filter is uninstalled for most of the testing described here.

*Used a compression test gauge and recorded 72psi after a few pulls on the start cord.

*Visually inspected the intake pipe (carb-to-engine). No visible cracks or breaks, and appears to be solidly connected.

*Having removed the carb bowl now a couple times after testing, I had to drain a little fuel out of the bowl each time, so it looks like there's no obstruction between the gas tank and carb.

*Am using fresh fuel for testing.

*When pressing the primer bulb I'm not seeing any fuel propelled into the carb throat.

*Spritzed a little starter fluid into the carb then pulled the start cord; the engine runs momentarily until that fuel is burned off.


Am considering installing a carb rebuild kit for the new gaskets, but wanted to see if anyone had any other advice first. Thanks for your input.
 

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you need a new air filter housing gasket. if i were you i would pull the carb off and clean it again. sometimes if an engines being stubborn it will take a lot of starting fluid before it will run on its own fuel
 

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"Ditto"....maybe next time you spray to start...spray some more arround outside of intake pipe while it's firing up...,maybe locate a air leak..! Only other possibility I can think of may be a limited travel [amost stuck closed] needle in seat, unable to flow fast enuf...even thou you verified some fuel in bowl..
 

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should be a 12H802-2639-B1 B&S Quantum engine.

sounds like the carb sat quite a while and you've got a good coat of varnish inside.
I would:
- disassemble carburetor (completely, including removal of throttle plate and throttle shaft, welsh plug, and needle and seat)
- soak the carb main body in solvent/carb cleaner/gasoline for a few hours
- blow out all passageways in carburetor main body
- clean main jet (brass nut that holds the float bowl to bottom of carb)
- reassemble with new parts (#498260 B&S carburetor kit)

and try it again.

IF the primer circuit is STILL not working:
- remove air cleaner housing
- remove primer bulb and screen from inner half of air cleaner housing
- thoroughly clean air cleaner housing and blow out that passageway between the primer bulb and the small port where it blows into the front end of the carburetor
- replace air cleaner gasket (#795629, which will come in the #498260 kit)

and then if the primer circuit is STILL not working:
- add another air cleaner gasket (#795269 B&S) because your air cleaner housing is warped (like 99% of them are) OR special-order a new air cleaner housing. (way cheaper to just stack two gaskets in there and it fixes the primer problem 9 times out of 10.)

(don't over-tighten the three 10-32 machine screws that hold the air cleaner housing to the front end of the carburetor and control bracket. tighten the two which attach the air cleaner housing to the carb FIRST (I think it's 40 inch pounds?) and then tighten the outer (upper right corner) one. don't hog 'em down too tight - that's why almost ALL of those are warped, causing the primer circuit to not function properly.)

* and of course you ALREADY pulled the little black wire off that runs between the coil and the brake and checked it carefully to be sure there are no abrasions/cuts on it that might cause it to ground out the coil, right? ;)

 

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After spray "priming'...eng should run on it's own ...since you saw the clog on main jet and cleared it..I wouldn't spend time [yet] on the primer system...just inject the spray and troubleshoot from there ...maybe your carb throttle plate is stuck closed, or gov spring it not holding it open? Feel with throttle with your finger...or prop it open ...worse case, replacement carbs are cheap now....IMO
 
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