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Discussion Starter · #1 ·
I have a Troybilt 20CS Weed eater.It acts like the flywheel key is striped. Key is OK
The start rope is hard to pull like to much compression.
Where are the valves in this ----.
What would release pressure to make it easier to start.




Thanks for answer & time.
Doorkeeper
 

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The model you mentioned has a 2 stroke engine, so it doesn't have valves. Since the key is ok, there could either be something wrong with the recoil assembly, or there could be internal damage causing binding. Also, excessive carbon buildup in the combustion chamber, or on the piston could cause this.
 

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If it somehow got turned in a position that allowed fuel/oil mix to run into the cylinder, that would make it hard to pull. If you have not already pull the spark plug and see if it loosens up to normal.
 

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Discussion Starter · #5 · (Edited)
I got it to crank for a minute, blowing smoke like crazy, then it started to knock so I stoped it.
I have finished tare down of the string trimmer & there is a layer of carbon on top of the piston appoximate 1/8" thick & some metal dings on edge of piston, no scratches on the piston bore (HEAD) walls.
What is My next move clean of carbon then sand of rough edgec of piston.
OH! There is carbon in the cylinder headsmall amount build up.
 

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I'm not sure that sanding a damaged piston is a great idea. You could try it if the damage isn't too bad. I would clean the carbon buildup on the head with a plastic brush or a wooden scraper. Don't use a wire brush or anything too scratchy! The carbon buildup was definitely what was causing the stiffness.
 

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.... The carbon buildup was definitely what was causing the stiffness.
1/8" would have certainly jacked the compression a bit. Sounds like the oil to fuel ratio used must have been on the high side (too much oil) or maybe it did a lot of idling. Wonder if a chunk of that coming loose would be enough to cause the ding in the piston? :dunno: Loose carbon will make a knock sound.

I remember one time dad had a 74 Olds Cutless and the ignition quit. He cranked it enough to end up flooding the engine. Family mechanic came out and found a wire had came loose in the distributor and got it running but sounded like it was trying cough up a marble. Mechanic said probably just loosened up some carbon from the raw fuel in the cylinders. Cleared up after running on down the road with it. Course back then, leaded gas old fashioned carb, points and condenser ignition, you take a car with a V8 out on a long uphill highway grade after it had been driven easy around town for awhile and hold it to the floor until it kicked out of second gear around 65 mph it would sound like a bunch of marbles running through it along with a nice cloud of grey fog. :D
 
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