# Craftsman no high speed..???



## kaferdave (Dec 1, 2014)

I have a Craftsman Easy Start weedeater. It fires right up, idles, but will not rev up to high speeds... changed the fuel lines, fuel filter, primer bulb, rebuilt the carb and had it in the ultrasound cleaner, still won't go much past idle, sound like it is laboring. Bought a brand new carb from Sears, thinking there was a passage in the old one that I couldn't unplug...no change, both carbs do the same thing. SO, I checked for any vacuum leaks, made sure the head bolts were tight, cleaned the screen (that didn't really need it) on the muffler...no change. After spending the $$$ on the new carb that I can't return, where would I go from here? Carb adjustment does nothing, both carbs are identical in (non) performance...wwhat gives?


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## jsouth (Jan 31, 2008)

Have you tried to run the trimmer, with the muffler off.It could have carbon buildup in the muffler.Also check to see if the exhaust port is clear no carbon buildup.Hope this helps.

Jerry


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## kaferdave (Dec 1, 2014)

jsouth, I haven't tried that, but I will...I assume for a short time, it's okay to run without the muffler, then?


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## kaferdave (Dec 1, 2014)

Jerry, thanks for the info, it didn't help top end, but it was sure a lot louder
I cleaned and scraped the muffler while I had it off, cleaned the exhaust port, but neither were really gunked up....I'm not sure where to go from here..after spending the $$ on the non-returnable carb, I don't really want to scrap the machine, it has to be something simple..but for the life of me I can't figure out what:freak:


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## jsouth (Jan 31, 2008)

Have you check the compression,with a compression tester.It should be 90# or better to run.I like it to be around 120#.If the compression is lower than 90#it could be a scored piston or cylinder or both.If both are ok,check for a stuck piston ring.You can press on the ring through the exhaust port with a screwdriver,to see if it will move,be careful not to scratch the piston.Also is the trigger opening the throttle wide open,when you press the trigger.Is your air filter clean,not soak with 2 cycle fuel.Hope this helps.

Jerry


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## kaferdave (Dec 1, 2014)

Jerry, thanks, I'll check that out today. It starts and idles just fine, so I am thinking the compression is okay, but I'll get in there and check the rings...the top of the piston looks great, a tiny tiny bit of carbon buildup, but certainly nothing that would make it do what it is doing.. I have restored complete cars and motorcycles, been around engines for over 50 years, so I'm not what would be called "mechanically challenged"... and the air cleaner is clean and dry, BTW...and full throttle really is full throttle...


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## 30yearTech (Sep 14, 2006)

Perhaps the problem is in the drive train. Check the drive shaft and cutting head to make sure there is no undue load on them preventing the engine from obtaining full rpm's.


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## kaferdave (Dec 1, 2014)

I have disconnected the whole driveshaft assembly, and lubed it, played with it, made sure it spins freely, I'm starting to get a little annoyed...I've spent a lot of time and a little $$ on this silly thing, and I don't want to let it beat me...it's a 2 stroke, centrifugal clutch (which, by the way, locks up tight at anything over idle, just like it should), I just don't get it. I've played with cars, motorcycles, lawn mowers, Bonneville Streamliners on 85% nitro, drag cars, VWs that run a street driven 10 second et in the 1/4 mile, and I hate to admit defeat on such a little, simple, thing...


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## finaprint (Jan 29, 2006)

I've put a few drops of oil in intake with carb removed and then shot a short squirt of starting fluid into the hole and crank it, if a carb/fuel issue it will start and rev high but don't do it for more than a second, the fluid with no oil mixed can scar cylinder walls.


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## Sir Thomas (Dec 7, 2013)

Nobody mentioned the flywheel. Pull and check if the key to the flywheel is sheared. I'm not saying this is the issue but if the flywheel key is sheared or worn the timing may not be right. Most of the Craftsmen has aluminum flywheels with the key built in and they shear easily. Also, I was looking back. No mention of spark check. You work on cars. Check the ohm resistant on the coil. Put the black on the plug to spark plug and the red on the stock (anywhere to ground). What reading are you getting if it's 0 or infinity the coil may be bad.
How old is the machine? The gaskets could get dry and lose sealing capacity. Just throwing out a bunch of ideas.


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