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#Post#: 60193--------------------------------------------------
Troy Bilt 4 cycle trimmer
By: 3000 FPS Date: August 5, 2015, 6:23 pm
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I received a Troy Bilt 4 cycle trimmer for free.
The problem was hard starting and once it started it would die
when trying to rev the engine.
So I replaced the carb which is a Walbro WYLA series.
The trimmer is still hard to start but it will rev alittle
better but it does not seem to go to a high enouph RPM to lock
the clutch in real well.
I checked the valve lash which is at .007.
I dumped the old fuel and put in known good fuel.
The compression is at 85 psi which seems low to me.
I made new gaskets for the intake and carb and made sure the
impulse is lined up correctly.
I checked the spark arrestor and no carbon build up at all.
It will also sometimes die for no reason and then hard to start
again.
I took the metering lever in the carb and raised it just alittle
to richen it up a bit.
I have tried also to adjust the carb needle and it does not
help.
Now the only thing that I can think of that is not right is the
compression.
So is 85 psi to low for a 4 cycle string trimmer putting it
right at the edge making it difficult to run but yet just enouph
to get it started.
#Post#: 60196--------------------------------------------------
Re: Troy Bilt 4 cycle trimmer
By: 660magnum Date: August 5, 2015, 7:20 pm
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I have something like one of those that the Dolmar dealer gave
me several years ago. I haven't bothered with it. He mentioned
some problem they seem to have with the cam?
#Post#: 60197--------------------------------------------------
Re: Troy Bilt 4 cycle trimmer
By: 3000 FPS Date: August 5, 2015, 7:30 pm
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Is it the intake lobe on the cam that worn down and not taking
in enouph fuel and also not creating enouph vacuum to work the
impulse.
I am trying to understand this so I can recognize this if I come
across it again.
What about the 85 psi, that seems low to me.
#Post#: 60198--------------------------------------------------
Re: Troy Bilt 4 cycle trimmer
By: 660magnum Date: August 5, 2015, 7:49 pm
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It's been a few years and hard to remember now? But the problem
was somehow related to the cam? Apparently the problem was more
involved than what the dealer wanted to mess with as he was a
Echo dealer. He had opted out with the customer.
85 psi does not sound good to me either?
#Post#: 60200--------------------------------------------------
Re: Troy Bilt 4 cycle trimmer
By: 3000 FPS Date: August 5, 2015, 8:02 pm
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I tore a different make 4 cycle trimmer apart last year and I
think the psi was more like 120.
#Post#: 60202--------------------------------------------------
Re: Troy Bilt 4 cycle trimmer
By: 660magnum Date: August 5, 2015, 8:19 pm
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120# is more like it.
#Post#: 60211--------------------------------------------------
Re: Troy Bilt 4 cycle trimmer
By: 3000 FPS Date: August 5, 2015, 10:17 pm
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I was on google and it popped up with a guy doing a compression
test on you tube for a Troy Bilt 4 cycle string trimmer.
He was able to hit 150 psi. Yep I think 85 is low.
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