Stihl 250, compression/pull starting issue

MMagis · Nov 4, 2015

I have a Stihl 250 that all of a sudden last year seemed to have too much compression. So much so that I can't pull start it more than a few times before the rope breaks. I've had a few ideas along the way that I thought fixed the problem, only to find out I was wrong. Originally, I was stripping out the pawl. I took it to the dealer and he put on a dual pawl for me, and that solved that issue, but now the rope continually breaks. Anyone ever had this issue before? I've bought the strongest rope I can find in that size, but maybe it's still not enough? It sure feels stronger than the original. It's never been easy to start with no compression release, but it's to the point I'm ready to throw it in the junk pile. Nothing more aggravating then being in the middle of a fence project and the chainsaw won't start. Then get it fixed and it breaks as soon as you get back out there.

dfkrug · Nov 4, 2015

I did have a similar problem with an old Echo, an all-magnesium unit. It would hydro-lock
from the chain lube oil leaking into the cylinder. Very strange....prob NOT what is happening
to your MS250, since it has a separate plastic oil tank.

What irritates me about these Stihls is the lack of a compression-release valve, a common
feature of similar-sized Huskies. You can add one, and I notice that some aftermkt cyl/piston
kits include them. The kit for an old 026 I had had a CR, and it really improved the saw.

Barry 1 · Nov 4, 2015

Pull the plug and crank it over when it does that,and see if gas blows out. Carb is probably leaking gas into the cylinder and hydro-locking it. I have this problem every couple of years.
You can get a new carb on Ebay for only $10.95 delivered.

MMagis · Nov 5, 2015

Thanks, that makes sense. I’ll take a look.

swines · Nov 7, 2015

What irritates me about these Stihls is the lack of a compression-release valve, a common
feature of similar-sized Huskies. You can add one, and I notice that some aftermkt cyl/piston
kits include them. The kit for an old 026 I had had a CR, and it really improved the saw.

The newer professional Stihl saws have a compression release. As an example, in a mid-size saw, the MS261 has a compression release.

ovrszd · Nov 7, 2015

Barry 1 said:
Pull the plug and crank it over when it does that,and see if gas blows out. Carb is probably leaking gas into the cylinder and hydro-locking it. I have this problem every couple of years.
You can get a new carb on Ebay for only $10.95 delivered.

Yep, sounds right to me.

I've got 2 250s, never had that problem but did have a new carb put on one when it started leaning out and dying all the time. Dealer installed, cost me $24.

dfkrug · Nov 7, 2015

swines said:
The newer professional Stihl saws have a compression release. As an example, in a
mid-size saw, the MS261 has a compression release.

Yes, some of the mid-size pro Stihls have compression release valves, and all of their big saws have it now.

But lowly homeowner Husqvarna Ranchers (e.g. the 455) have CR, but he Stihl Farm Boss (MS290) does not.
These 2 saw compete head-to-head. I don't know if the new MS291 has it.

IMO, any saw over 50cc should have CR.

Mysfyt · Nov 7, 2015

First thought I had is maybe the flywheel key is sheared and it is too advanced.

Giles · Nov 24, 2015

I have two gas hedgers a Stihl and an Echo. The Stihl is their so called "easy start" that has nearly 200 pounds of compression!
My wife does 90% of the hedge trimming but can't begin to start the Stihl. She has absolutely no problem with the Echo. Both are the same size engines and I rebuilt both.
On a positive note for the Stihl--it is MUCH SMOOTHER then the Echo.