Any small engine experts here?

JohnCU

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Dec 9, 2000
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I just got one of those cheap, feather-weight Weedeater brand blowers from Walmart since I just wanted to do some casual leaf blowing and it was cheap. It ran fine for a while, but now if I take the choke off completely it shuts off. It will run decently with half choke. I took the air-filter off and tried to see what was going on. It opens up completely as it should with the choke off, but still cuts off with the air filter off. I checked the spark plug and it looked clean, although there was a little gas around the rim. I looked inside and it looked black.

I'm sure the gas mixture is correct, and there are no idle adjustments or anything... any ideas?
 

ValValline

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Feb 18, 2005
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If you are forced to run with at least partial choke, then you have a fuel delivery or mixture problem. The choke basically limits that amount of air, which results in a richer fuel mixture. The mixutre may be right, but is it stale? How old is the mix? As fuel ages it loses octane and becomes harder to burn.

If there are no adjustments, then I would look into taking the carb (or what passes for a carb on something that small) apart and clean the orifices that the fuel flows through.
 

JohnCU

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Dec 9, 2000
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Originally posted by: ValValline
If you are forced to run with at least partial choke, then you have a fuel delivery or mixture problem. The choke basically limits that amount of air, which results in a richer fuel mixture. The mixutre may be right, but is it stale? How old is the mix? As fuel ages it loses octane and becomes harder to burn.

If there are no adjustments, then I would look into taking the carb (or what passes for a carb on something that small) apart and clean the orifices that the fuel flows through.

Mixture isn't stale, I just bought a new bottle of the recommended oil and mixed it with fresh gas in a brand new container.
 

Ornery

Lifer
Oct 9, 1999
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Still got the receipt?

I nursed a POS Homelite blower along for close to ten years, but I'd have been money ahead buying a good one in the first place.
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
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Are you letting it warm up half choked before you take it off?

If so..

It's a fuel delivery problem.

That means either carburetor.. You did drain the gas last season, right?..

Unfortunately, for 2 cycle engines, fuel delivery is also related to the mechanical soundness of the engine.

Do a compression check. Under 100PSI and the engine is toast; you probably used TCW-III specced 2-cycle oil.
 

JohnCU

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Dec 9, 2000
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Originally posted by: Eli
Are you letting it warm up half choked before you take it off?

If so..

It's a fuel delivery problem.

That means either carburetor.. You did drain the gas last season, right?..

Unfortunately, for 2 cycle engines, fuel delivery is also related to the mechanical soundness of the engine.

Do a compression check. Under 100PSI and the engine is toast; you probably used TCW-III specced 2-cycle oil.

All 2-cycle oils aren't the same? I got the Poulan two cycle oil that was right beside the blower at the store...
 

wesman6

Senior member
Jan 5, 2001
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Try opening the gas cap just a little so the tank can breathe. If that works, your vented cap is the problem.

As it's new my other fix won't work. It mostly has to do with a stored weedeater's carb getting gummed up with oil as the fuel evaporates. This usually only happens if you have it sitting for a long period of time though.

Have you adjusted the carb at all?
 

arcas

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Apr 10, 2001
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No, there are differences in 2-cycle oils. TCW-III type works best on low-RPM 2-cycle engines such as marine outboards. Sounds like you bought the "right" stuff. Now, that said, oil types is kind of a religious argument and you'll find people who've run TCW-III in their brushcutters for years with no ill effects.

How old is the blower? Did you thoroughly mix the oil+gas mixture before adding to the tank? Are you letting the engine warm up? (this might not be necessary, depending on the engine...I've never played with a Weedeater brand).

If it runs only with the choke partially-engaged, it sounds like a fuel delivery problem. Could be as simple as a clogged fuel filter in the gas tank. Check that first since it's trivial to replace.

If it's not the filter, it's time to start looking at the carburetor. Could be a partially-clogged jet. Does it run for a few seconds with the choke wide open after you pump the primer a few times? If so, it could be a problem with the needle (maybe a stuck spring?). Depending on how much you paid for your blower, it may be worth your time to take the carburetor apart and clean it. If you've never done this sort of thing before, figure it'll take a couple hours. 2-cycle carbs for weedeaters and blowers are really simple beasts, typically only a couple moving parts and a tiny spring but the orifices are so small that they can clog if you don't winterize properly.

To do it right, you'll need to head to your local lawn/garden shop and buy the correct "carb rebuild kit" for your model (usually less than $10) so you can install new gaskets when you reassemble. If you're careful, you can reuse your old gaskets if they're in good shape. Having some sort of workbench or table and good lighting will help immensely.

/finally got around to rebuilding the carb for his Stihl brushcutter last weekend
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
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Go ahead and let it run half choked for a good .. 15 minutes, and report back?

It could help clear any gummy deposits in the carb, if that's the problem.