Engine doesn't want to run. Craftsman 21HP 46" cut, Model 91728852, engine B&S Platinum 331977

bertsmobile1

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  • / Engine doesn't want to run. Craftsman 21HP 46" cut, Model 91728852, engine B&S Platinum 331977
Slowy,
Please go back & read the entire thead before you post a response which is factually correct but totally wrong for the problem at hand.
The engine has a glowing pipe with the choke ON so is not likely to be running lean & thus too hot.
It is just confusing people .
 

charleneje

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  • / Engine doesn't want to run. Craftsman 21HP 46" cut, Model 91728852, engine B&S Platinum 331977
Okay I feel like such an idiot, after being so careful about how I replaced the head gasket. By the time I replaced the carburetor I was in alot of pain in my back and just replaced it without paying attention to what I was doing and didn't connect the relay wire at the bottom of the carb.
When I went out and rechecked everything I came in and put my last reply with the picture showing that I had the piston at the correct top dead center.
I went back out to the mower I decided to just put all the covers on it and put it undercover until I could come up with a possible remedy and as I was putting the cover on I noticed the wire hanging that I should have connected to the carburetor once connected I started the mower and it ran perfectly,
What this proved was I (a) should have been more careful when I replaced the carb., and (b) the relay on the bottom of the original carb was the initial cause of the motor not running without the choke, so I could have just changed the relay hanging of the bottom of the float chamber.

I really want to thank all of you that tried hard to help me get this engine running I know its difficult trying to figure out what could be wrong with an engine when it isn't actually in front of you and even more difficult when the problem ended up being something that was missed when reassembled. THANK YOU ALL
 

slomo

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  • / Engine doesn't want to run. Craftsman 21HP 46" cut, Model 91728852, engine B&S Platinum 331977
Slowy,
Please go back & read the entire thead before you post a response which is factually correct but totally wrong for the problem at hand.
The engine has a glowing pipe with the choke ON so is not likely to be running lean & thus too hot.
It is just confusing people .
From what the OP wrote "when I started it up it didn't want to run except with the choke on".

That told me pilot circuit was clogged and engine wanted more fuel (choke).

Far as a red muffler goes, could be rich or lean. Let me know what I'm missing out on. Ears are open.

He said the plug looked normal with the choke on. Again sounds lean to me. If it was running proper, running the choke would blacken the plug till it burned off. '

If you lean out a motor the exhaust will glow red. Entire header pipes will be red. Some where around 15:1 A/F ratio.

slomo
 
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