Stihl HS45 Trimmer won’t stay running or take throttle.

[Rwhitebbq]

Pre-2001 HS45 was initially very hard to start (15-20 pulls).

In an attempt to correct this, I have:
- changed fuel
- installed new air and fuel filters
- new plug
- new carb
- cleaned spark arrestor screen
- new coil (found NOS at a dealer)

Now it starts on the first few pulls (likely due to the new coil), but won’t take any throttle without dying. If I set it down, it will run untouched for 15-30 seconds and then dies.

I haven’t torn it apart but it hasn’t been used much over the years, so it seems unlikely it has worn rings, etc.

Thanks in advance for any ideas to try next.

 

[Michael Rupley]

Adjust the low speed adjustment out 1/2 turn.

 

[hacskaroly]

I haven’t torn it apart but it hasn’t been used much over the years, so it seems unlikely it has worn rings

Pulling the muffler off will give you a view of the piston on the exhaust side, you can see the rings from there and gauge if there is any damage or not. You can also pull the spark plug and look in from there to see if there is any scoring on the exhaust side of the cylinder. If you pull the carb then you can see from the intake side the piston and rings for a visual inspection.

As noted from above, you may need to adjust your new carburetor. Sometimes it is best to reset it and adjust from there.

Here is the information from the HS 45 Manual

 

[Rwhitebbq]

Thanks. Adjusting both low and high speed screws, and then setting idle seems to have done it. Appreciate the responses.

I also have 2 Stihl blowers, a trimmer, and a chainsaw, and have never had to tweak a carb!