MS 170 with major issues!!

[1CallLandscape]

my stihl ms170 topping saw has some major issues that i cant figure out... it will run ( sometimes) flawlessly until its hot, but other times i can cut for an hour with it while hot and its fine.. then when i let off and back to an idle after a cut it stalls out and is a royal ##### to re start, sometimes it will restart after 40 pulls! WTF!!

it has great spark ( ive tested it while running and not running) is getting fuel cause it does run, ive also cleaned the fuel tank vent out, new spark plug

any ideas????? cause im stumped, and i need to get this annoying thing working right cause i have a big prune job to do on saturday! please help!

 

[Stihl-Pioneer]

It could be the coil acting up when it gets hot enough(see it happen on outboards)or possibly vaporlock from the heat.Does it start fine when cold? Have you changed your fuel to a different octane or brand?

 

[1CallLandscape]

i had thought about the coil but never dug any deeper into it, i run 93 octane in all of my equipment, with stihl oil, the saw is ported too. i had thought about the vaporlock and thats why i cleaned out the fuel tank vent, sometimes they get clogged with chip dust

 

[ms290]

I had almost the same issues with mine. CHECK MUFFLER SCREEN!!!!!!!! as i have seen this is a VERY common trait of these saws.

 

[1CallLandscape]

I had almost the same issues with mine. CHECK MUFFLER SCREEN!!!!!!!! as i have seen this is a VERY common trait of these saws.

mine is out and exhaust is pretty much gutted out to accomadate the port job

 

[Dan_IN_MN]

My thought is coil also.

Oh.....I'm confused on three little letters in your post....Do they stand for Where's the Fun?

Dan

 

[1CallLandscape]

My thought is coil also.

Oh.....I'm confused on three little letters in your post....Do they stand for Where's the Fun?

Dan

ill test the coil today and they stand for What The F@#$

 

[Dan_IN_MN]

ill test the coil today......

It could test good cold and go bad when hot. If you're depending on this saw for work, I'd replace the coil...... There's not much to a two stroke..... they either run or don't.

Regards,

Dan

 

[Mike PA]

Another vote for the coil. Can be an intermittent problem that only will be seen when hot. Friends 029 was doing the same thing. PITA until the coil was changed.

 

[Fish]

Inspect the fuel line.

 

[K7NUT]

There's not much to a two stroke..... they either run or don't.

Regards,

Dan

I may be off base here, but I had a problem with my 064AV that drove me nuts!
After doing everything it didn't need, I did the "maintenance" issue's we should always be checking, the spark plug wire was bad!
It could be your coil, but change your wire, there cheap and that will also make your coil test true. I tested the spark and I had spark, but I could'nt tell how much or if it was sparking when I put it back in the hole?
Bought new wire from the dealer BTF and away she went!
BTW, with a new crankcase seal on the right and ALL new rubber lines, gas and oil!

 

[Dan_IN_MN]

I may be off base here, but I had a problem with my 064AV that drove me nuts!
After doing everything it didn't need, I did the "maintenance" issue's we should always be checking, the spark plug wire was bad!
It could be your coil, but change your wire, there cheap and that will also make your coil test true. I tested the spark and I had spark, but I could'nt tell how much or if it was sparking when I put it back in the hole?
Bought new wire from the dealer BTF and away she went!
BTW, with a new crankcase seal on the right and ALL new rubber lines, gas and oil!

k7NUT

How did you find out it was the wire. BTW good call! I'd replace the wire over the coil any day!

Dan

 

[ms290]

Just how ported is your little tree slayer? What did you do to adjust the high side of the carb?

 

[sefh3]

I'm going to go out on a limb and say your coil is good but your grounding wire is loose or bad.

 

[Dan_IN_MN]

I'm going to go out on a limb and say your coil is good but your grounding wire is loose or bad.

I can understand if the saw doesn't want to shut off if the wire is loose.

I can understand if the saw kills in mid cut or while running if the grounding wire is bad.....however, that saw is just about all plastic and there isn't much the wire can ground against...... (from what I can remember)

FWIW....This is my 1000 post..... :spam:

Regards

Dan

 

[Dan_IN_MN]

Just how ported is your little tree slayer? What did you do to adjust the high side of the carb?

Both good questions! Doesn't this saw have a "fixed" H jet?

Dan

 

[ms290]

Both good questions! Doesn't this saw have a "fixed" H jet?

Dan

Mine does. So does my dads but they are the older models. MFG in 08 i think.

 

[blsnelling]

Did you install an adjustable carb? If not, and it's ported, then you're not getting enough fuel and it's getting to hot.

 

[ms290]

Did you install an adjustable carb? If not, and it's ported, then you're not getting enough fuel and it's getting to hot.

Brad what carb can i get that can be adjusted and fit my 170? One of the walbo carbs is prefered but i will use a tillotson too.

 

[blsnelling]

Brad what carb can i get that can be adjusted and fit my 170? One of the walbo carbs is prefered but i will use a tillotson too.

It's in one of my old threads somewhere. I'm not sure, but seems like it may have been a WT315. Whatever it was, it fits a 025.