I need help with a small engine please?
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Senior User
Joined: Dec 2011
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From: East Bernstadt Kentucky
I need help with a small engine please?
I have an almost new McCulloch chainsaw, I just replaced all of the fuel line exactly where they need to be. I can get it started but it dies after it burns the fuel in the carb, it will stay running if I press the primer bulb every 5 seconds or so, I tried running it with the gas cap and exhaust off of it, it isn't sucking fuel into the carb. What could cause this?
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Sounds like the carb needs a good cleaning. Blow out the carb real good with an air compressor and use a safety pin to clean out the tiny holes. Check to see if there is a screen in the muffler, if so pull it out. Suppose to be a spark arrestor but they get clogged up and the engine can't breath. Might want to check the air cleaner filter see if is dirty. A new spark plug won't hurt some 2 cycle's go thur them fast.
If you clean the carb open the needle and blow thur the inlet and feel/listen if your get air thur. Doesn't take much to clog the small passage way.
If you clean the carb open the needle and blow thur the inlet and feel/listen if your get air thur. Doesn't take much to clog the small passage way.
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Check the fuel pump gasket while the carb is a part. If ripped or hard replace it. Check carb gasket for damage, if it leaks can suck in air and cause problems. I think a good cleaning will do the trick just make sure you get good air flow from gas inlet passage with the needle valve push open. Good luck!
Small hole (pin size) in fuel line can cause a like problem but sounds like you have that cover.
Small hole (pin size) in fuel line can cause a like problem but sounds like you have that cover.
Thread Starter
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Senior User
Joined: Dec 2011
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From: East Bernstadt Kentucky
I replaced the fuel lines and the filter, also tried to run it without the filter, it will run if I pump fuel to it with the primer bulb but isn't sucking fuel in on its own, the fuel/accelerator pump looks fine, im going to take the carb apart completely and replace everything I can. I have 2 other saws that run I just enjoy fixing things.
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Elder User
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If all does not work it could be time for new rings and maybe piston. Replaced many on my redmax blowers and fixed the problem. Bad rings low compression, not even to suck fuel into combustion chamber.
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From: North of Tulsa, Oklahoma
Did you replace the primer bulb? If there is a tiny pinhole it will suck air and not gas. My weedeater gave me that problem last year. The pin hole was so small that it did not leak gas out the primer bulb, but it was big enough to suck air, not gas.
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Yea good to check, some equipment it will cause problems some not. A pin hole in the fuel line or bulb can be hard to find and can drive you a little crazy trying to figure out. Been there done that.
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Interesting, never of that before. Sounds like it would work good, will have to give it a try!
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From: PA
When you take that carb apart you can get to all of the passages. If you can use fine copper wire to poke out the holes. If you have to use a pin don't enlarged any holes. The thick diaphragm pumper is what is wrong with the saw. It is probably stiff and it won't pump the fuel. Those carbs use the pulse of the crankcase on a two stroke to pump the fuel. Just make sure it goes back together exactly as it came apart. Use gaskets only, unless you be damned careful not to get any gasket sealer in any holes. Some oils that are used in the fuel mix are not that good as I have found out by experience. I've worked on many of those carbs because the oil stiffened up the diaphragm when letting the saw sit for months on end. I use Jonsered or Husqvarna oils now and can let that saw sit for a year and they will start. CB