Demon fs450

[lewis16]

I have this massive pain in the caboose stihl fs450 brush cutter which is just being a pig.

It has had a new piston and cylinder as the last one was toast, scored and rings held in.

Carb kit, it was leaking out of one of the gaskets when primed. New gaskets and diaphragms.

Now the issue is, it didn't run when it came to me and it had almost no compression.

It will fire when you spray carb cleaner in the carb and put the choke on, then abruptly stop. Won't run off choke at all. I've swapped the primer lines round and there is not different result really. I am running out of things to try. Just won't seem to take off. Plenty of compression, spark is healthy too.

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[ANewSawyer]

So you have already done a pressure and vac test right? What were the results of it?

New fuel lines and fuel filter?

 

[lewis16]

No I havn't vac tested yet. He doesn't want to pay for it lol

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[ANewSawyer]

He has a FS 450 but doesn't want to pay for a test? Who else thinks that is what roached his first piston? Idk, not much you can do without a pressure and vac test. I bet it has a large enough leak to keep it from running. Have you tried fiddling with the carb screws? I am sure you have.

 

[lewis16]

I set them back to stock just to rule it out. Guess I'll just have to pressure test it. He payed for a meteor piston and cylinder but had me fit them, he tried to clean the carb and tore the gaskets which he had to pay to replace. I suggested a pressure and vac test but I said I'd have to charge more and he said no

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[ANewSawyer]

Wonder if he runs 150:1 just to save on oil...

 

[Conquistador3]

Do a pressure test and then charge it as part of labor to fix what you'll find to be the problem.
It will save you a lot a lot of time.

 

[chainsawman2011]

If it passes leak test it more than likely will need a new carb


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[ANewSawyer]

Was wondering if there is a update on this.