Stihl Trimmer Hard To Start

[PearlWhiteGT]

Howdy fellas, I found a Stihl FS 55R string trimmer on someone’s curb for free and trying to see if I can get it going. When I try to pull the rope to start it. It’s very hard. I removed the spark plug and it turns over very easily. Put the spark plug back in and hard to pull. Fuel tank was empty and the trimmer doesn’t look abused. I removed the screen on the muffler and it was very clean. It’s a 2 stroke so no valves to adjust. Any advice on what might be going on or what to check next would be much appreciated. Thanks.

 

[beaglebriar]

Give this a try. For 15 bucks you have basically nothing to lose. I brought back a fs76 a couple years ago with a Chinese carb….still going strong

 

[Shane¹]

I would dump a little gas in the intake and see if it starts then try the china carb like @beaglebriar said. I have several of these and I have had to replace OEM and chinese carbs every few years 1 seems to go bad. If it doesn't start check for spark and go from there

 

[IffykidMn]

I fail to understand what the carburetor would have to do with pulling over difficult.

perhaps try pulling muffler and check condition of rings, piston and cylinder.

 

[Shane¹]

It pulls over fine with the spark plug out but hard with it? Either wrong plug maybe? Is the piston hitting the plug? How hard does it pull over? Sounds like it just has a lot of compression which would be a good thing

 

[PearlWhiteGT]

It pulls over fine with the spark plug out but hard with it? Either wrong plug maybe? Is the piston hitting the plug? How hard does it pull over? Sounds like it just has a lot of compression which would be a good thing

Correct, pulls hard with plug in. Can’t even pull it correctly to try and start it. Doesn’t appear that it’s the wrong plug but will double check.

 

[Shane¹]

Does it try to spin the head when you pull it over? Maybe the clutch could be stuck?

 

[PearlWhiteGT]

Does it try to spin the head when you pull it over? Maybe the clutch could be stuck?

No the head doesn’t spin when I pull the cord.

 

[bogieboy]

If it spins over fine with no plug, and it has the proper plug (bosch usr6 or ngk bpmr7a, or equivalent), i would look at if the flywheel has sheared the key, if you cant pull it over right... may be trying to ignite the fuel too early. I had an fs55 for a while, and it was not that difficult to start, my wife could start it no problem.... however the 55 does have a bit more snap to it than a 56, and requires a pretty swift snap of the cord once pawls are engaged, as it doesnt have the ez-start damped style of recoil, its just spool-pawls-drive cup.

 

[hotajax]

I have same problem, of course mother-in-law says I'm all effed up. But I was thinking that something with a little lubricant, like Carb cleaner, would be as good as the WD-40 someone else suggested. Quick shot in spark plug hole.