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Discussion Starter #1
So I recently acquired a McCULLOCH MAC 3227 string trimmer. I have been trying to get it to start. I replaced the fuel lines, spark plug, and the primer bulb. I also cleaned out the Carburetor. Still no start, I have no clue what the problem is at this point.

Thanks for the help!
 

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Check for Fire/Fuel/Compression, needed for the combustion engine to run.


Simple Test Ideas:
  • Pull and ground the plug on metal of the engine and pull as starting and look for a blue spark at plug’s tip.
  • Pull the plug and prime cyl with a teaspoon of fuel mix, replace plug and try to start.
  • Check the compression with a gauge or your finger s/n be able to hold the comp in cyl while trying to start.
These cks could give you indications where the prob is. Most of all do you have any past hist on the Eng.
  • Was it stored off season with untreated fuel in the eng and has not started since?
  • Did the eng stop while in use as if it got hot and stopped.
  • How old is the eng and what conditions are the fuel lines and fuel filter.
 

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Discussion Starter #3
I have tested all those "simple test ideas," and still it won't start.

When I found it the fuel tank was empty and everything was dry, since I found it I haven't been able to start it, and I replaced all the fuel lines and the fuel filter was in very good condition. Everything seems to be in working order, it just won't start up. I have gotten it to turn over a few times but then it dies.
 

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1.If it tried to go and was bone dry it could be a restricted carb from old fuel IMO. Have you opened the carb inspected and verified with carb cleaner or wire that ALL ports are open (with the mixture screws removed)?
2.A lesser method is to add 2 oz of carb cleaner to fresh fuel and try to get it flowing as it trys to start to possibly remove any restriction.
3.The best method to clean varnish from old gas evaporating is to strip the carb (adjustment needles and all and soak the carb in cleaner 8 hrs). Again verify all ports are open.
4.Know your specs on high low carb adjustments or starting points and tweak from there.

Other suggestions:
1.How much compression is the cyl producing? I usually expect 100 psi or c/n hold it in with my finger.
2.Pull the muffler and inspect the piston, ring and cyl for no wear marks, carbon and ring not stuck in piston.

Good Luck!
 

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just a newbie here, but not to small engine repair. I want to ask how you determined the fuel filter was good? If the trimmer sat long enough for all the gas to evaporate, the filter could be gummed up with varnish,too.
a great majority of the repairs I get with "wont start" or "rough running" are on equipment that has been stored for a period of time. as jow mentioned, gas today can gum up a carb if left in for a period of time. carbs on small engines are rather sensitive to any dirt or varnish and cleaning them should be a thorough job. I can still get amazed when I run a guitar string through a passage and see the crud that was in there.

but start with jows suggestion of pullin off the muffler and ispect and a compression test.
 

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I agree that it would be a good idea to check the filter. Also, when you disassembled the carb, did check the condition of the diaphragms? They often deteriorate and lose their elasticity after a while, especially with Ethanol gas.
 

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I had a Mac 3227 for YEARS...I wish I still had it ! Besides all the items that were discussed, when you remove the muffler, make sure the muffler is not stopped with mud from a wasp ! I had to de-mud mine at the beginning of every season due to a no/hard start problem.
 
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