# Craftsman yt4500 carburetor problem and solution



## Geezer_ga (Jul 18, 2011)

Folks, wanted to post very quickly that, for reasons too complicated to go into here, I bought a yt4500 a couple of years ago and it ended up being used barely, if at all, over the two years after purchase. When I needed to fire it up again this week (after a battery recharge, of course), needless to say, it wouldn't oblige. I had read that using gas which hade not been seasoned for storage would gum up the works and so I focused on the carb. (I hadn't seasoned tha gas with any additive.) There was a spark for sure, and the fuel pump was delivering gas to the carb. I dismantled the air intake part and sprayed a bunch of cleaner into the carb with no effect. Eventually, I pulled the bowl off the carb. It was full and it crossed my mind, as I threw the gas away, that it was a bit yellowish, but I didn't think anything more of it. After a bowl clean and (since I'm way too chicken to pull the carb off and clean it up) a skoosh of carb cleaner up through the only jet I could see (which appeared to pass through the jet readily), I realized that whatever that electronic thing at the bottom of the bowl was; it was kinda stuck. And it was. This thing is supposed to click and move when current is applied to it. Mine was just static, regardless of current. Actually, it was just kinda stuck. Some manipulation and some carb cleaner later, I had freed up the little spike in the bottom. Some people call this the anti-backfire solenoid. And mine was a bit rusted up and wouldn't operate. Anyway, once I had it moving again and had tested it out by grounding the bowl body against the [-] terminal and touching the red wite against the [+] of the battery, it produced some rusty crap for a while as it moved and when it was clean (after some manual up-and-down and -round-and-round manipulation) I reassembled it and turned the key. Suddenly, everything worked great. So keep that in mind if you have a similar problem, because I'd never even heard of such a thing. Incidentally, I have a slight sensation that I'm going to have to replace this thing because of one or two very slight bumps in performance, and because it did produce a lot of cruddy ussty looking crap when it was being freed up, but at least I know what the issue is, and how to fix it. I guess the moral of the story is, machinery runs at its best when it runs regularly. So the deal was completely my fault, but I hope that someone else benefits from my experience. 

In summary: if you have a spark and fuel being delivered to the carb, but not reaching the plugs, suspect the anti-backfire solenoid. Dismantle the bowl and test the solenoid's operation. 

Quick test: turn the ignition on, and have your ear close to the carb. If there's a click from the carb when you turn the key, your solenoid's probably okay. Mine made no click. It was stuck. Regards to all. - Jery


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF :wave:

Thanks for the info.

Yes newer engines use them, older ones don't.

BG


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