HT 135 WON'T RUN FULL TILT

[Wizard]

New tree saw, won't cut full tilt, only half throttle with seemingly reduced power. Checked valves, were set at 0.012", so I set to 0.004" (book). Carb linkage full range of motion.

Any ideas with this?

 

[J D]

What kind of saw?
If it's new take it back.
I'd suspect a fuel line, filter, or carb issue.

 

[Bullseye T&L]

New, or new to you? How well have you gone through it? I assume if you've played with the valves, then you've probably checked the mix settings.

 

[Wizard]

Yes, it's a new pole saw, used it 3 times, adjusted valves, tried needle jet settings, no change with throttle problem.

So, I'll ck the fuel filter, or replace, & ck for kinks. If that doesn't resolve the problem, I could pull carb and ck high speed circuit.

Or, perhaps I should just return for troubleshooting.

I posted cuz was wondering if these models have a glitch.

 

[lone wolf]

Did you check the exhaust for restrictions? You sure the butterfly is opening all the way ? A video of this might help.
Did this happen after it was running well or come this way?
Maybe the carb isn't adjusted right. The coil comes to mind, but a video is needed. Are you able to turn the H and L jets or are they requiring a special STIHL screwdriver?

 

[Wizard]

Yes, throttle plate has full range of motion.

 

[lone wolf]

Yes, throttle plate has full range of motion.

Can you video it?

 

[Wizard]

Did you check the exhaust for restrictions? You sure the butterfly is opening all the way ? A video of this might help.
Did this happen after it was running well or come this way?
Maybe the carb isn't adjusted right. The coil comes to mind but a video is needed.

I'll ck the exhaust.

This ran like this from new in the box. I have adjusted carb a number of times. Seems like fuel starvation on full throttle, but runs what seems like less than full throttle when at half throttle (doggy). Stalls at full throttle, runs at half throttle.

Throttle cable is adjusted correctly.

 

[lone wolf]

I'll ck the exhaust.

This ran like this from new in the box. I have adjusted carb a number of times. Seems like fuel starvation on full throttle, but runs what seems like less than full throttle when at half throttle (doggy). Stalls at full throttle, runs at half throttle.

Throttle cable is adjusted correctly.

Those carbs are real tricky to adjust, try a bit more. The H mainly from what you are saying. I wonder if the needle valve isn't set right?

 

[Wizard]

The exhaust screen is about 1/4 carboned, but not plugged, probably from running 1/2 throttle. I don't think that is the problem, because it didn't rpm when new.

 

[lone wolf]

The exhaust screen is about 1/4 carboned, but not plugged, probably from running 1/2 throttle. I don't think that is the problem, because it didn't rpm when new.

Burn it off, that might do it. Worth a try. The fact that it carboned up that quick up tells me its running rich try leaning the H.

 

[Bullseye T&L]

My HT131 is a real booger to adjust the mix settings. It's way more sensitive to tuning than a 2-stroke. Maybe try the adjusting jets, just itty bitty turns though. I dinked around with mine one time, and it was such PITA to get back to normal, I've never touched it again.

 

[Wizard]

My HT131 is a real booger to adjust the mix settings. It's way more sensitive to tuning than a 2-stroke. Maybe try the adjusting jets, just itty bitty turns though. I dinked around with mine one time, and it was such PITA to get back to normal, I've never touched it again.

Thanks for telling me that. I have went both ways under load, will try smaller increments.

 

[lone wolf]

Thanks for telling me that. I have went both ways under load, will try smaller increments.

Go 1 turn leaner on the H and see what happens. Do you have a tach?

 

[lone wolf]

My HT131 is a real booger to adjust the mix settings. It's way more sensitive to tuning than a 2-stroke. Maybe try the adjusting jets, just itty bitty turns though. I dinked around with mine one time, and it was such PITA to get back to normal, I've never touched it again.

They suck to tune! I try to never touch them.

 

[Wizard]

Go 1 turn leaner on the H and see what happens. Do you have a tach?

I have a tach.

 

[lone wolf]

I have a tach.

What will it tach up to currently?

 

[cscltd]

Can’t really tach a ht135 the rev limiter will kick in.
Some mistake the rev limiter for not running correctly.
Put it in a large dia wood and see if it smooths out.
If new and under warranty, take it back to dealer.
Screwing around with it only costs you time and coin and upsets dealer when you decide to take it to him for warranty repair.

 

[babaoriley]

Check the chain tension, sometimes too tight saw won’t run right either. Since you’re at it, check if it oils as well.

 

[stihltech]

Rev limiter yes. It will sound terrible out of the wood. It is not like a chain saw.
What matters is how it acts with a SHARP chain in the wood using at least 1/2 of the bar.
If it does not smooth out then, there is an issue. Take it back. That is what warranty is for.