MS251 no start

[a. palmer jr.]

Currently working on a friend's MS251 that he says "doesn't run right". I tried it and couldn't get it to start at all. Anyway, he says he installed a new ignition module on it and it does appear to have spark but maybe not on time. My question is: Does the MS251 regular saw and the MS251 with Easy Start use the same module? I've been doing some reading and have gotten conflicting information about this. I think Media Cat just calls for one coil but I went on ebay and other sites and they list a bunch of different part numbers for this module. I know they use a different flywheel.

 

[SteveSr]

Currently working on a friend's MS251 that he says "doesn't run right". I tried it and couldn't get it to start at all. Anyway, he says he installed a new ignition module on it and it does appear to have spark but maybe not on time. My question is: Does the MS251 regular saw and the MS251 with Easy Start use the same module? I've been doing some reading and have gotten conflicting information about this. I think Media Cat just calls for one coil but I went on ebay and other sites and they list a bunch of different part numbers for this module. I know they use a different flywheel.

If the coils are mounted on the same location i.e. cylinder on both variants then the coils are the same.

 

[a. palmer jr.]

If the coils are mounted on the same location i.e. cylinder on both variants then the coils are the same.

All I know is that the coil is located above the flywheel on this one. I never got to see the other coil, I assume it was located in the same place.
I have read somewhere that the easy start saws use a coil that has the timing slightly retarded so it's easier on the spring but then as the engine revs up it advances.

 

[atpchas]

IPL shows 2 FWs for the 251. Unclear what the diff is.

 

[DND 9000]

No it is clear and can be seen which one is for which version. The one is for the C-BE versions which use different starter housings and pawls.

 

[SteveSr]

All I know is that the coil is located above the flywheel on this one. I never got to see the other coil, I assume it was located in the same place.
I have read somewhere that the easy start saws use a coil that has the timing slightly retarded so it's easier on the spring but then as the engine revs up it advances.

The IPL shows 2 flywheels but only 1 coil type so they are the same.

 

[a. palmer jr.]

I may have to rig me up a timing light to see if the spark is occurring at the right time. I looked at the coil today and it was an off brand with no part number on it. It has spark but I'd say not as good as my other Stihl saws.

 

[SteveSr]

I may have to rig me up a timing light to see if the spark is occurring at the right time. I looked at the coil today and it was an off brand with no part number on it. It has spark but I'd say not as good as my other Stihl saws.

So what happened to the original coil?

 

[a. palmer jr.]

So what happened to the original coil?

I don't know. The saw was given to me to fix after the shop gave up on it, I guess. I don't know what they did with the coil they removed. I would guess it's in a dumpster. I have a couple of modules for small Stihl saws somewhere in the garage, I plan to look for them tomorrow, maybe one will fit the 251.

 

[a. palmer jr.]

I found a new coil in my shop that looked like the one in the saw so I tried it. I put a small amount of fuel in the spark plug hole and yanked on the rope and it hit a couple of times and then died and wouldn't hit anymore. I tried it again with no success. For some reason the starter rope is hard to pull the first time or two then becomes easy. This saw has no compression release but feels like it after the first two pulls. The piston looks okay but maybe it could have weak rings or something; I had a Husqvarna like that, caused by cat. converter and overheating..