Stihl FS45, HS80 and HS45-z All Stalling under Acceleration

[S Haase]

Hi Guys,

I'm new here and this is my first post. A bit about me..., I like to play and tinker with any engines I can find, usually get them given from familly to fix or buy them not running, service them and get them running good and sell them and start over.

Anyway I have four Sthil machines that I can't get going and I have no idea why?? They all start and Idle fine but when you give them gas they bog down and stall. I have cleaned the flame screen in all of them, Carbs cleaned, worst ones I have put new carb kit in them, Also tried a cheap ebay carb replacement but always the same result, starts and runs fine but bogs down on throttle.

This happens with two FS45, A HS45-z and a HS80..

Using fresh fuel with all of them. Only cleaned the plugs.

What do you guys think? Or what should I be testing/ Looking for?

Thankyou

Thank You

Thanks

 

[S Haase]

The low speed jet is adjusted wrong and most likely the throttle stop as well.

You need to decide if they are dieing from being too rich or too lean then adjust the low speed needle accordingly.

You should start by adjusting the high speed needle just slightly rich then after that do the low.
If the main jet is clean then you should be able to start a hot engine with the throttle wide open.
Take heed of what dfbroxy posted because the difference between runs like a pearler and wizz BANG ; scrap metal can be as little as 1/2 turn on a needle.

Initial settings are
FS 45; L-1 , H-0.75
HS 45; L-1 , H-0.75
HS 80; L-1 , H-0.75

If they do not start on those setting then something is very wrong

Thank You very much

 

[The Specialist]

Thanks

Your exhaust may be blocked!!!!

 

[The Specialist]

Thank You

Thanks

Remove your exhaust and have a look in the port. You can have a wall of carbon across the port. Remove if you do. Look at the piston. Does it have "barcodes" on it or score marks as what it is known. If it does, the engine has to be rebuilt! If it is ok. Check the exhaust to ensure exhaust is getting out. If all of that is O.K. Change the fuel filter in the tank. In hedge trimmers the part number is 0000 350 3513. When you get the old one out, blow into it. You should be able to blow quite free! replace the fuel filter. You cant blow them out with an air compressor!!! Put a new one in. If that still has not fixed the problem, the 10 micon screen in the carb may have a sludge or dirt in it. That will have to be cleaned out. You can email me at dvata@yahoo.com if you need help with this.