Stihl FS45 Trimmer Engine Problem

[JTL]

I have a fs45 trimmer that i can not figure out what the problem is thought someone could help.I put a carb on it thought that was what it was but still doing the same.I can full choke it and it will idle but when i go to give it throttle it just dies.I can go to half choke and it will go full power than like it runs out of gas.It has a zama carb on it now which is just got one air screw i back it out 1 1/2 turns still didnt help than i changed the intake off thinking it might have a pin hole in it that didnt help either.Could it be a gas tank?Do these models have a filter in the tank or not i cant see one in there?Its like its sucking air from some were but i just cant seem to figure this one out.Im also thinking it might be the head gasket could it be bad?Im not no mechanic but i do know a little about how to work on things i just need someone to tell me what to check for or what to look for.



Thanks For Any Info!
John

 

[KennyV]

WELCOME to LMF John...

How old are the fuel lines? They will crack and fail, or get mushy and expand to where they do not fit tight...
Here is a youtube covering R&R fuel lines Stihl FS38 Fuel Line Replacement - YouTube
on a Stihl trimmer... :smile:KennyV

 

[SONOFADOCKER]

Get them in the shop all the time - fuel lines get hard or crack and suck air .

 

[JTL]

WELCOME to LMF John...

How old are the fuel lines? They will crack and fail, or get mushy and expand to where they do not fit tight...
Here is a youtube covering R&R fuel lines Stihl FS38 Fuel Line Replacement - YouTube
on a Stihl trimmer... :smile:KennyV

OK,i will check them good i just thought that if they wasnt leaking that they are ok but i will check them.What is good compression on these trimmers?


Thanks John

 

[Edwards saw service]

Good compression should be between 85 and 100 psi.

Edwards Saw Service in Glen Mills PA

 

[jteuban]

Spark arrestor screen as well

 

[benski]

As mentioned, I'll bet your fuel lines will do the trick. The spark arrestor tip is a good one, and heck, throw in a new spark plug, too.:thumbsup::biggrin:

 

[JTL]

Ok,ill try everything you guys have mentioned and let you know what happens.


Thanks For Help!