171 hardley revs and has no power

[motolife313]

Sorry. It was red-85. You the man! Thank you Harleyt also!

 

[clint53]

At the local Stihl dealer here they have a poster on the wall showing the effects of mixing the Oil/Gas ratio wrong.
As you have found out now, stay with 50:1

 

[DND 9000]

Will it be too lean to run it with no filter screen? The carb h screw is maxed out from the factory so I can’t go any richer on the carb

You have to use a tach and check the rpms, then you will know. But it can be tricky with the electric speed governor in the ignition module. Rpm`s can be within specification, but it can be set on the lean site. (limit is 13.500 rpm) If it is nessessary to richen your carb, go to your dealer, or if you know what you do, remove the limiter cap and richen the H screw a bit.

 

[mountainlake]

I think the winner is RED, he mentioned the screen first. Steve

 

[HarleyT]

Here. It shows you how to remove the limiter caps.

 

[motolife313]

At the local Stihl dealer here they have a poster on the wall showing the effects of mixing the Oil/Gas ratio wrong.
As you have found out now, stay with 50:1

I actually usually mix it up 40-1 since I run it in my 064 and 075. Probably had about 32.1 mix

 

[motolife313]

You have to use a tach and check the rpms, then you will know. But it can be tricky with the electric speed governor in the ignition module. Rpm`s can be within specification, but it can be set on the lean site. (limit is 13.500 rpm) If it is nessessary to richen your carb, go to your dealer, or if you know what you do, remove the limiter cap and richen the H screw a bit.

Ok thank you. I can hear the rpm with my ear very well. I’ll know if it’s hitting more rpm when using it today later thank you. Probably just clean the screen and put it back in to be safe

 

[lone wolf]

I’m going to take it to the dealer before I even change the plug. Do I tell them I ran non ethanol or ethanol? I run both. Just don’t want to void the warranty

They will test the fuel in the tank.

 

[clint53]

I actually usually mix it up 40-1 since I run it in my 064 and 075. Probably had about 32.1 mix

Not in my Stihl's. Always Stihl oil and always 50:1.
My first Stihl from 1985 is still running. Haven't even changed a spark plug.

 

[SteveSr]

Well the winner is Harleyt! I took the carb apart and clean it and same problem, I thought right away it’s gota be that screen then mentioned on here. It was clogged.took it out and runs great now. Revs high idle also when first starting. Thank you for the help guys.
Will it be too lean to run it with no filter screen? The carb h screw is maxed out from the factory so I can’t go any richer on the carb View attachment 869754

I don't know about the changes to the 171 vs 170/180 but I have seen this same issue on a MS180. I think that it has to do with multiple small exit holes in the muffler don't allow the screen to get hot enough to burn off. Other contributors are too much oil and part throttle operation.

Yes, removing it will make it run leaner which is a BAD thing on the 170/180 with the non-adjustable fixed jet carb. Don't know what the setup is with the 171. The screen will also keep curious insects from finding a home in your engine during the off season.

 

[RED-85-Z51]

Glad you got it going, those screens have sent alot of saws to the landfill


Sent from my LM-G820 using Tapatalk

 

[motolife313]

I actually did notice it hit less rpm when running richer for the first time a long time ago. Maybe I’ll run it leaner so the little thing has more power

 

[SteveSr]

I actually did notice it hit less rpm when running richer for the first time a long time ago. Maybe I’ll run it leaner so the little thing has more power

A clogged exhaust screen will also make it run richer as it will keep some of the incoming charge from escaping through the muffler. Be careful how you tune it. There is a VERY fine line between max power and lean seizure. Tuning is dependant on altitude and air temperature. This was an issue with the predecessor 170/180 with the fixed jet carbs.

 

[motolife313]

I meant oil lean not fuel lean

 

[mountainlake]

I thought the 170 180 weren't adjustable. Steve

 

[SteveSr]

I thought the 170 180 weren't adjustable. Steve

I think that is what I said. Never seen a 171/181 strato saw.

 

[HarleyT]

One must be sure to check the air filter, as a clogged one will make it run rich. And trying to adjust that out will come back to bite you if someone cleans the air filter later

 

[motolife313]

That’s why I didn’t want to lean the carb out during the problem with my saw like someone recommended