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Discussion Starter #1
engine wouldn't crank so I pulled the plug and she cranked fine but blew a ton of gas out of the spark plug hole! On checking the carb is full of gas also - have it drying out right now (gas disconnected) anyone have any ideas on how to proceed? It is a B&S 31c707 17.5 HP.

Thanks in advance.
 

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Discussion Starter #2
Well it seems to be only spitting oil out of the spark plug hole now so I cleaned up that mess and put the plug back in. Cleaned up the carb and ordered a rebuild kit for it.

Now I am going to go crank that thing up...if you don't hear from me again I was blown to ****. Otherwise I will change the oil and let you know how it went :)
 

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Discussion Starter #3
Well I didn't blow up! But it still will not crank but half a turn with the plug in.

I even spun her with the plug out until nothing but air came out.

So off comes the valve cover next - hope the ole match book cover feeler gauge still applies!
 

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Sounds like you have a stuck carburetor float or debris in the needle valve which prevents it from shutting off the fuel.
 

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Superdave!
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It sounds like you washed the piston and rings with quite a bit of gas. Wouldn't hurt to put a few drops of oil in the spark plug hole before you try to start it again.
 

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Cub Cadet Junkie
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Might want to check the oil too to make sure there isn't tons of gas in it. Gas doesn't lube as well as oil..
 

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MTF Junior Poster Esq.
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Fuel line shut off valve. I put them in everything I have. Cheaper than a rebuild. Doesn't take much for a needle to not seat.

That's why all the older tractors had a shut off.
 

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Tractor Junkie
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I had the same problem, fix the sticky float then Change the oil, run for a few minutes, drain and refill.
 

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"Well I didn't blow up! But it still will not crank but half a turn with the plug in."

This is an indication of one of two things, either the cylinder is full of gas, you already said you cranked it until nothing came out, OR the valves need adjusting.

I have pages copied from the B&S Service Manual for your engine on adjusting valves IF you would like them. Address below, put in proper format.

Walt Conner
wconner5 at verizon dot net
 

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Discussion Starter #10
Thanks for the advice guys.

I pulled off the valve cover and it was full of gas. Got her 1/4" past TDC on the compression stroke and man the clearance was WAY off. Set the intake to .004 and outake to .005.

Put a fuel cutoff valve on the fuel line as I won't have the carb kit for a few more days. Also through in a new spark plug.

Sucker fired up so fast it startled me! I ran it for about 6 minutes just to warm her up. I knew the valve adjustment had fixed the original problem but I also knew the carb was still going to be a problem.

Changed the oil again and then just for the **** of it I turned on the gas cutoff valve and let it sit 5 minutes. Went to crank her and BAM - no go - she wouldn't turn over more than half a turn.

Turned off the gas cutoff valve - pulled the plug - spun her for 20 seconds - put plug back in - just before cranking again - turned on the gas valve - BAM - fired right up.

Later - to stop the engine I just turned the gas valve off and let her die.

Then after I would shut her down with the gas valve and she would always restart no problem.

So it was a valve problem combined with the carb problem - hope that helps someone down the line.

Had to get the lawn mowed today as it has been a few weeks and grass was about 10" high, so I didn't bother putting the hood on or the side panels - it may have looked funny to my neighbors - but mission accomplished!

Thanks for your suggestions - much appreciated!
:trink39:
 

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In many of these cases you'll find a cracked carburetor intake manifold. Obvious signs is overfilled oil. Meaning gas is now mixed with your oil. Be careful not to ignore this. Better to repalce one part then a complete shortbolck.
 
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