Craftsman YS4500 Briggs and Stratton 21HP Intek Single Cylinder Problem

[StarTech]

Hmmm. Wrong torque and key PN. Per APSI 82 and 89.

Engine before code 120701xxxxxxx now uses new steel key PN 796335 . Engine after code 120630xxxxxx uses new longer steel key PN 591757.

Flywheel torque was increased from 100 ft-lbs to 110 fl-lbs. They also added a washer under the bolt on 330000 series but I don't have that PN at hand.

 

[MasonH]

UPDATE #8763: She Runs PERFECTLY! I rekeyed the flywheel ensuring it slid in all the way and torqued it down to 100 ft-lbs. Since the timing was about 180 out I rechecked valve clearances, etc. Mower still would not start. I went ahead and installed the new Walbro I had purchased and still it would not start - it was turning over nicely but not catching. Checked spark and the valve clearances (AGAIN!) - and all looked well. Now, I suspected lack of fuel getting to the carb itself - when I removed the back-fire solenoid very little gas came out of the float bowl. I removed the gas tank and dumped all the old gas - and I sprayed thru the small outlet nipple, and checked the hoses were clear - refilled with fresh gas - still no start! Now my wife says "Lets dump it..." but I said nope not giving up yet! I took my auxilliary gas tank I use for my motorcycles and bypassed the tank and the (NEW) fuel filter and mower started and ran like a charm with no surging and a beautiful idle and throttle response. Now I put it all back together with NEW fuel filter - and no start! Next I removed the (NEW) fuel filter entirely and voila! Perfect start and smooth running! I assume that I was given a fuel filter that is not correct for this B&S 21hp single cylinder (see photo attached) as I just checked the one from the Sears part's website which is a flat pancake style (like the old one that I threw away) - and the engine cannot draw the gas thru it (?). Perhaps this fuel filter is for the twin engine models with a fuel pump that pushes the fuel through? Anyway - after doing a happy dance to the Mower Gods and calling the wife out to witness - I am overjoyed and now can get back to the business of mowing the lawn. I hope this may save folks the pain and agony and to check that fuel filter is the correct one if you are having surging and/or no-start issues
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[MasonH]

Hmmm. Wrong torque and key PN. Per APSI 82 and 89.

Engine before code 120701xxxxxxx now uses new steel key PN 796335 . Engine after code 120630xxxxxx uses new longer steel key PN 591757.

Flywheel torque was increased from 100 ft-lbs to 110 fl-lbs. They also added a washer under the bolt on 330000 series but I don't have that PN at hand.

Ah - okay I will torque it to 110 ft-lbs - but not sure about the key part # you mention? I got the part from a local supplier - and the same one I see listed: Part #222698S. I had actually looked for the washer on the parts diagram but it is not shown for this engine. THanks!

 

[Rivets]

If you don’t have a flywheel washer, 100 ft. lb. is fine.

 

[Scrubcadet10]

glad you got her going!

 

[MasonH]

Thanks to all for your help!

 

[StarTech]

Local supplier will just sell you what ever you ask for.

Maybe I need to post the links to the APSI's before anyone will believe me about those Briggs spec changes that were made back in 2012 and 2013. Boy some are soo stubborn, but will listen to those uTuber that don't have an idea of what they are doing. Btw I got the actual keys here and both are steel; unless, aluminum is now attracting magnets.

APSI 82
APSI 89

 

[Rivets]

He’s talking about me, because he knows so much more than me. That’s why you have to read and follow my signature.