Project Stumpbroke Stihl FS250

[Stumpys Customs]

Yup, you read the title right. I Had a FS250 trimmer power head sent to be broke. I didn't get any vids of it so you'll have to take my word for it on how it turned out. This was a fun project for me & thought I'd share it.

Since all I had was the power head I had to borrow a shaft from my oldest boy's FS90.

Got the covers off.

 

[Stumpys Customs]

I couldn't take to much off of the squish band because the piston would free port on the ex side @ TDC.

Machined the base to get .025" squish clearance.

 

[Stumpys Customs]

Some pics of the stock ports

 

[Buffhunter]

LMAO this is awesome!!!!!!! You had to go do this stump didnt you...... now im gonna have to send mine to ya........

 

[Stumpys Customs]

And some pics of them finnished

 

[Stumpys Customs]

LMAO this is awesome!!!!!!! You had to go do this stump didnt you...... now im gonna have to send mine to ya........

Send it on over Might as well have a smile on yer face will yer weed whackin.:msp_biggrin:

 

[shougcuo]

Thank you for your sharing，awesome.

 

[Stumpys Customs]

I only got a couple of pics of the muffler. I didn't get any of it while I had it apart to gut it.

I added another port for more breathing room. Sounds pretty good.

Here's some timing numbers
Stock duration
EX 152
TR 106
IN 136
BD 23

Modded Duration
Ex 152
TR 110
IN 156
BD 21

That's all I got for this one.

 

[NPKenny]

This picture is worth a thousand words to me! Thanks for sharing.

 

[Stumpys Customs]

This picture is worth a thousand words to me! Thanks for sharing.

No problem. That's what it's all about.

 

[jropo]

I also like how Stumpy did those transfers. Clean.

 

[Hedgerow]

It's gonna need heavier duty string now...
Just sayin...
:msp_rolleyes:

 

[Stumpys Customs]

It's gonna need heavier duty string now...
Just sayin...
:msp_rolleyes:

Steel cable..........:msp_w00t:

 

[Saw Dr.]

Unless that thing was worn out, I cannot figure how someone would need more power than a stock 250. Anyway, nice work. Make sure the gearhead has plenty of grease. Stihl uses a bigger gearhead on all of the trimmers larger than the 250.

 

[Roll Tide]

Neat but that stock gearbox wont hold up to the extra power if running blades.

 

[johnnichols]

Follow up

Hello to all AS. Just wanted to share with everyone how well the FS-250 has been doing.
Since Sandy came thru the area where I live and work it has been an ongoing task to get all things back in order. Some here know I work for a gas company and have somewhere around 50 miles or so of offroad I travel daily. With that said when we started clearing we cut just enough to get our trucks thru to our well and compressor sites. Time was very important because when something is not running thousands of dollars can be lost each hour.
I've been using my pole saw attachment on the trimmer and along with various saws have been going back over my roads clearing them compleatly this time around. I've used over 20 gal. of fuel mixed at 32:1 with Stihl Ultra thru the trimmer and I believe its still getting stronger. I'm thinkin' it uses almost twice the fuel as it did stock, or close to it, but its well worth it. You just can't bog the thing down!
When I sent the thing to Stumpy, 10 years of hard use had took its toll. Looking to get another 10.

Thanks and God bless you Stumpy!!!
John Nichols