Sthil FS55R not running.

[Hottech]

After discovering that there was no visible spark I replaced the coil and had a very strong and clear spark it still would not run. Replaced the carburetor, fuel filter, air filter and fuel tank just for good matters it still would not run. Confused and discussed I dropped it off at a Sthil dealership for the knowledge of knowing where I went wrong. The dealership had a 5 week wait for repairs but I felt that it would be in my garage for at least that length of time not being fixed. After 5 weeks I was told by the mechanic that it could not be fixed and the sales rep was trying to convince me to buy a new one. I was certain that anything mechanical could be fixed and google searched this forum. Could not find what I was looking for but was given the Sthil 1-800 # and connected to the technical help line. The tech immediately diagnosed that I had a bad coil and that the timing of the coil was off. Even though I had a good spark it was at the wrong interval. Who would have imagined that the small black coil was programed for timing. Replace the coil and it fired up like brand new. A lesson learned don't give up just because you though the dealership was an expert. A very happy camper and glad to have my Sthil trimmer working again.

 

[Fish]

So the original coil was bad, and the first replacement the incorrect one?
For what it is worth, their fs38 is the same powerhead, and the whole thing sells for $129 new.

 

[Hammermechanicman]

Was the coil OEM or aftermarket? I have had folks buy Ebay and amazon coils for stihls that look and fit the same as the OEM coil but the timing is wrong.

 

[bertsmobile1]

Could not find what I was looking for but was given the Sthil 1-800 # and connected to the technical help line. The tech immediately diagnosed that I had a bad coil and that the timing of the coil was off. Even though I had a good spark it was at the wrong interval. Who would have imagined that the small black coil was programed for timing. Replace the coil and it fired up like brand new. A lesson learned don't give up just because you though the dealership was an expert. A very happy camper and glad to have my Sthil trimmer working again.

Every one who repairs small engines and every mechanic trained since 1901 knows how a Kettering ignition works.
Every one who was not asleep during their science classes would know how coil works .

Glad you got it fixed.
For future reference when you have fuel compression & spark but no bangs, the next thing to do is check the timing ( roughly ) by locating the position of the piston and comparing it to the position of the magnet & coil legs .
Occasionally when really stumped I have put a white line down one of the coil lamination legs & onto the flywheel then hook up a strobe light & spin the engine with a power drill to see where the sparks were happening with respect to the piston position.
FWIW should be some where around 30 deg before TDC.
Been caught out with wrong coils more than once

 

[Hammermechanicman]

My father who was born in 1911 used to joke that charles Kettering was a terrible person. When folks asked why he thought that he would say it was because he invented the electric car starter. Then folks would ask why that was a bad thing and he would say that before the electric starter women couldn't drive cars.
Da dum tss.
Living near Dayton Ohio the kettering name is still very prominent.
City of kettering
Kettering hospital
Kettering foundation
Kettering health network
Kettering labs

 

[bertsmobile1]

My father who was born in 1911 used to joke that charles Kettering was a terrible person. When folks asked why he thought that he would say it was because he invented the electric car starter. Then folks would ask why that was a bad thing and he would say that before the electric starter women couldn't drive cars.
Da dum tss.
Living near Dayton Ohio the kettering name is still very prominent.
City of kettering
Kettering hospital
Kettering foundation
Kettering health network
Kettering labs

Hammer you just made my day
Also learned some thing because I always thought Kettering was an Irish man ( I will of course check )

 

[Hammermechanicman]

He did most of his inventing in dayton ohio. They have some interesting displays of his and the wright brothers in the Dayton Engineers Club. He founded Delco. (Dayton Electric Company). He invented the electric cach register while working for NCR. He also partnered with the wright brothers when they started their airplane company.

 

[slomo]

He did most of his inventing in dayton ohio. They have some interesting displays of his and the wright brothers in the Dayton Engineers Club. He founded Delco. (Dayton Electric Company). He invented the electric cach register while working for NCR. He also partnered with the wright brothers when they started their airplane company.

Imagine people like this, going to school on dirt floors. And today we (USA) have the poorest edu'macation standards in the world. Pouring millions into schools and such. They did it on a peanut budget.

slomo

 

[StarTech]

He did most of his inventing in dayton ohio. They have some interesting displays of his and the wright brothers in the Dayton Engineers Club. He founded Delco. (Dayton Electric Company). He invented the electric cach register while working for NCR. He also partnered with the wright brothers when they started their airplane company.

Never heard of a "cach register" and I worked on a lot of cash registers

What is cach register?

Imagine people like this, going to school on dirt floors. And today we (USA) have the poorest edu'macation standards in the world. Pouring millions into schools and such. They did it on a peanut budget.

slomo

Schools tend just run the students through like cattle. For me English was one of my poorest subjects until I went to 6 weeks of Summer school after the 10th grade. I went from failing it to "A's". Just takes teachers that care about teaching instead just drawing a pay check. Of course having only an hour to deal with 50 students at a time is hard too. Now for me nearly failing History is my fault as I hated it. One of my History teachers just couldn't understand why I barely pass it and but had A+ in electronics.

 

[Hammermechanicman]

Yeah , cash register. My thumbs and phone keyboard not the best combination.