Poulan Pro trimmer clutches

[Hokiefyd]

I work in an office that does a lot of commodity recycling, but we also get equipment and other stuff in. Last week, we got a like-new Poulan Pro string trimmer, with a 30cc 2-stroke engine. Symptoms were it didn't start or ran rough. Nobody wanted it so I took it home. I took the recoil off the back and spun the starter cup by hand and there was a metal scraping. Not good. So I took the power head off the trimmer shaft to begin to open the engine up. To my surprise, the flywheel on the front of the power head was LOOSE on the front of the crankshaft. All it needed was tightening that nut. The key wasn't even sheared. After that, the engine spun smooth, and it started up fine. And it runs strong.

Problem is, I have to run it at pretty much full speed to get any speed on the trimmer line. It's got a typical flyweight clutch system on the front of the flywheel. The faster the flywheel spins, the flyweights will expand out, engaging with the clutch housing attached to the trimmer head drive. At anywhere but full speed/full throttle, the trimmer line will bog down in thick grass, and I can even get it to stop pretty easily by pushing the trimmer head into the ground. With my Echo GT-200R, I seem to get full clutch engagement right off idle. In fact, I often trim with the throttle just cracked open, or at most half throttle, because I just don't need the engine at full whack to get results from the trimmer line.

I'm not sure what I can adjust on this Poulan Pro. Is this just the way it's designed? It's like the flyweight spring is too tight and it's holding the weights in. I can imagine having a spring that's too loose or broken, needing replacement. But a spring that's too tight?

 

[lars11]

dont know what to adjust. But is it a trimmer with the "bent pipe" gear? They may need some breaking in in my experience. Before that the axle to the head have a bit too much resistance. It may feel peppier after a few hours work.

 

[Hokiefyd]

It is a curved shaft trimmer. There is no gear in the trimmer head...it's a flexible cable inside the curved shaft.

 

[lars11]

yeah, run it for a while and see if the clutch sets better and that the cable softens a bit. But I think these are sort of meant to go full open or idle...

 

[Hokiefyd]

Thanks. The Echo is very progressive, and I really like that about it. I can rev it up just off idle for very light trimming and it works great. This Poulan won't even start to spin the trimmer head until it reaches about halfway up the engine speed range. Once it reaches full speed, that trimmer head is spinning stupid fast, and impossible to stop. It's very "rubber band"-ey in its operation (if that makes any sense).

 

[Fordiesel69]

Thanks. The Echo is very progressive, and I really like that about it. I can rev it up just off idle for very light trimming and it works great. This Poulan won't even start to spin the trimmer head until it reaches about halfway up the engine speed range. Once it reaches full speed, that trimmer head is spinning stupid fast, and impossible to stop. It's very "rubber band"-ey in its operation (if that makes any sense).

I can confirm on a rebadge craftsman version of this trimmer it operated exactly as you describe.

 

[mk378]

Yes think of the trigger as idle and go. Two positions. They are designed to work at wide open like a chain saw. Running part throttle causes clutch wear. Speaking of that the clutch (both the shoes and the drum) is a wear item and will lose its grip when worn out.

 

[yeehaw1960]

As the centrifugal clutch assembly loosened (before getting too loose to run) it probably damaged itself. Cheap replacements on Ebay.

Some McCulloch clutches I've seen had rubber-like inerts. Strange. Another cost saving thing gone wrong.