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Stihl FS45 Trimmer Engine Problem

#1

J

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


#2

K

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


#3

SONOFADOCKER

SONOFADOCKER

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


#4

J

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


#5

Edwards saw service

Edwards saw service

Good compression should be between 85 and 100 psi.

Edwards Saw Service in Glen Mills PA


#6

J

jteuban

Spark arrestor screen as well


#7

B

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:


#8

J

JTL

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


Thanks For Help!


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