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JON, Small Engine Technician
Category: Small Engine
Satisfied Customers: 1214
Experience:  Certified Small Engine Technician
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Stihl fs 55c trimmer good compression cleaned out carb new

Customer Question

Stihl fs 55c trimmer good compression cleaned out carb new coil.
pops when primed thru spark plug hole...butt won't start or run.
replaced carb with new one...still won't start or run
Submitted: 4 months ago.
Category: Small Engine
Expert:  JON replied 4 months ago.
Have you removed and cleaned the spark arrestor in the muffler?
Customer: replied 4 months ago.
no...trimmer was running fine for 1/2 hour but would not restart after that...then I replaced carb aand runs a little when primed in plug hole
Expert:  JON replied 4 months ago.

If you have replaced the carb and properly installed new coil with proper coil gap it may not be able to exhaust properly if the exhaust port is stopped up. It is a common issue with Stihl machines. How do the fuel lines and fuel filter look? it sounds like it is a fuel issue, and new lines and filter are the only thing remaining if it is exhausting properly

Customer: replied 4 months ago.
fuel issue...fuel lines and filter are clear...gas comes to primer bulb. .010" gap on coil and it seems to be sparking well.
it is a lot of disassembly to get the muffler off, are you sure this is a problem?
Expert:  JON replied 4 months ago.

You shouldn't have to pull exhaust off to remove spark arrestor.

Expert:  JON replied 4 months ago.

Look at where the exhaust port exits machine. Should be able to put a 5/8" socket on it and remove it

Customer: replied 4 months ago.
You must be thinking of a different 5/8" nut...both plastic covers must be removed to get to the muffler/spark arrester....then drive shaft is loose and difficult to re align
Expert:  JON replied 4 months ago.
Customer: replied 4 months ago.
my machine does not look like has a catalytic converter for california
Expert:  JON replied 4 months ago.

Ah, didn't know that info sorry. Yes, you will nee to pull plastics off then. Sorry for not asking, as I am in Tennessee and we do not have the same emissions

Customer: replied 4 months ago.
Sorry, I should have told you that first, I will disassemble if you think it's REALLY necessary...
Expert:  JON replied 4 months ago.
Let me know what exhaust port looks like
Customer: replied 4 months ago.
Can't justify taking plastic's running a couple of seconds when's a fuel issue...I have cleaned the Zamma carb
but can't take out welch plugs to get to passages inside...maybe carbureter cleaner soak? carb is internet bought...looks exactly same but doesn't say Zamma...could be bad even though new?
Expert:  JON replied 4 months ago.

Can be, but not very common. You have all new fuel system pretty much, so.... nothing else really to check. New lines, New filter, new carb, gasket is good? Nothing else is fuel related.