FS85X just does not want to tune in properly

bertsmobile1

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Just to be different.
Please start a new thread with your new problem
1) it avoids confusion
2) it stops people reading 2 pages of stuff that has no relevance to your current problem.
See you there
 

PTmowerMech

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Leave it till you have the time to put in.
It is not like the tool will blow up, it is just annoying.

A small leak at the impulse line, the coil air gap being slightly too big, all of these make little difference to the high speed running will make the idle erratic.
It is one of those things that is oft diagnosed by ear.
A plug that is slightly out of size.

Usually you can hear if it is stalling out rich or lean.
The easiest work around is to richen the L to the point that it hangs when you accelerate.

Now it could be just the H & L jets being out of adjustment as mentioned before there are times I have needed to adjust the needles through 4 or more cycles before I get it right.
It just depends where the cross over L to H is.

I have fooled myself on more than one occasion and had a carb running on just the H needle.
With older carbs it is easy because the adjustment is coarse so if going from rich stall to lean stall was more than 3/4 of a turn you knew you had a problem
1) needle or jet damaged
2) running on the other jet

The new EPA compliant ones are harder because the taper is shallower so 2.5 turns of them is 1 turn of the old ones.

You must have a hell of a set of ears. Being able to tell if a 2 cycle dies because it's too rich or lean, baffles me. When one dies, I just hear it die.

LOL... I have tinnitus, so buzzing is what I hear mostly.
 

bertsmobile1

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You must have a hell of a set of ears. Being able to tell if a 2 cycle dies because it's too rich or lean, baffles me. When one dies, I just hear it die.

LOL... I have tinnitus, so buzzing is what I hear mostly.

So do I and most mechanics that I know
Next time your are tuning the H needle , take it a little too far in both directions till the engine actually stops.
Too rich will 8 stroke, miss a bit then just peter out with the odd bang or two before it stops
The exhaust becomes deeper in sound and sort of fluffy
Too lean will just keep on getting faster then nothing
The exhaust note will become higher and sharper like a blue smoke with a resonant exhaust pipe.
Two totally different sounds
 

PTmowerMech

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So do I and most mechanics that I know
Next time your are tuning the H needle , take it a little too far in both directions till the engine actually stops.
Too rich will 8 stroke, miss a bit then just peter out with the odd bang or two before it stops
The exhaust becomes deeper in sound and sort of fluffy
Too lean will just keep on getting faster then nothing
The exhaust note will become higher and sharper like a blue smoke with a resonant exhaust pipe.
Two totally different sounds

Very good explanation. Thank you.

This forum seriously needs a thank you button.
 

HotnDusty

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Very good explanation. Thank you.

This forum seriously needs a thank you button.

Yes, a thank you button would be good. Some posts are so informative and thorough, and deserve recognition of the time and effort taken to freely help others.

While I'm here.. Thank you!
 

bertsmobile1

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Yes, a thank you button would be good. Some posts are so informative and thorough, and deserve recognition of the time and effort taken to freely help others.

While I'm here.. Thank you!

Not a big fan of LIKE , THANKS etc etc.
Always better to do it as a post.
It very quickly leads to ego problems and people seeking gratification from getting the most likes.
It also tends to prevent people being blunt and oft a blunt answer is exactly what is required to get the OP to see reality.
Many seem to think this is rude, but wrong is wrong no matter how you dress it.
However the very best "thank you" is a "got it fixed and it is working great" post.
Then others who read the thread will realize that the fix worked.
 

Fish

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I would be a big fan of cash,
or better, a Paypal button....
 

PTmowerMech

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Not a big fan of LIKE , THANKS etc etc.
Always better to do it as a post.
It very quickly leads to ego problems and people seeking gratification from getting the most likes.
It also tends to prevent people being blunt and oft a blunt answer is exactly what is required to get the OP to see reality.
Many seem to think this is rude, but wrong is wrong no matter how you dress it.
However the very best "thank you" is a "got it fixed and it is working great" post.
Then others who read the thread will realize that the fix worked.

LOL... You'd spend a lot of your time looking at all the liked posts you made. he he he he he.
 
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