Problem with my Jon cutter.

[Help Wanted]

In need of advice. Just replaced cylinder and piston. Left bar and chain off and ran 2 tank Fulls of 25 to1 mix through it. Put chain and bar back on. Fires up great and screams with throttle pressed. Problem is it will not idle. It slows and dies after a few seconds of releasing throttle. Tried adjusting the low on carb with no change.

 

[bwalker]

Why in the world would you run it for two tanks with no bar and chain?
Sounds like an air leak, which is probably what fried the saw the first time.

 

[Mad Professor]

Why did it need a P/C? Did you replace seals and check intake air boot? Any work/cleaning of carb done?

Carb or air leak. Pres/vac test is a good place to start before it fries another piston.

 

[NSEric]

Which joncutter is it?
The 5800 has the best cylinder for those clone saws on it, most every replacement is a downgrade and will require retuning.

 

[Help Wanted]

Why did it need a P/C? Did you replace seals and check intake air boot? Any work/cleaning of carb done?

Carb or air leak. Pres/vac test is a good place to start before it fries another piston.

Piston and cylinder were scored no compression. My guess is it was running to lean. Going to pull the carb and inspect / clean. Replace seals and give it another try. I ran without chain and bar at idle to break in piston and cylinder. It ran at a very low rpm with 25 to 1 mix.

 

[Help Wanted]

Which joncutter is it?
The 5800 has the best cylinder for those clone saws on it, most every replacement is a downgrade and will require retuning.

Yep 5800. Runs great other than I can't get it to idle without stalling.

 

[Help Wanted]

Just had it apart again. Piston and cylinder great shape, very good compression. Carb is clean and seals are also looking good. I adjusted carb per directions. H 1-3/8, L-1-1/4.

 

[Old2stroke]

Do a search on how to tune the carb. You can't ever expect a particular number of turns out on the screws to be exactly correct, just gets you close and if it's an AM carb, screws could have a different thread pitch and "turns" setting could be way off.

 

[bwalker]

Piston and cylinder were scored no compression. My guess is it was running to lean. Going to pull the carb and inspect / clean. Replace seals and give it another try. I ran without chain and bar at idle to break in piston and cylinder. It ran at a very low rpm with 25 to 1 mix.

There isn't a worse way to break in a two cycle motor than to do what you did.

 

[Help Wanted]

There isn't a worse way to break in a two cycle motor than to do what you did.

Ok I get it. 2 YouTube pros with 25 years of experience and own their own shops are incorrect. Please refrain from your comments if you have no problem-solving advice!! Thanks

 

[bwalker]

Ok I get it. 2 YouTube pros with 25 years of experience and own their own shops are incorrect. Please refrain from your comments if you have no problem-solving advice!! Thanks

Yep and not surprising given you tube.

 

[pioneerguy600]

In need of advice. Just replaced cylinder and piston. Left bar and chain off and ran 2 tank Fulls of 25 to1 mix through it. Put chain and bar back on. Fires up great and screams with throttle pressed. Problem is it will not idle. It slows and dies after a few seconds of releasing throttle. Tried adjusting the low on carb with no change.

You have a fuel delivery problem to the cylinder, it will need you to figure it out on your end, no amount of guessing from members will fix it on here.

 

[Mad Professor]

Ok I get it. 2 YouTube pros with 25 years of experience and own their own shops are incorrect. Please refrain from your comments if you have no problem-solving advice!! Thanks

Youtube is as reliable as Wiki and the MSM for reliable information. Still believe in "safe and effective" too?

 

[bwalker]

You have a fuel delivery problem to the cylinder, it will need you to figure it out on your end, no amount of guessing from members will fix it on here.

He probably has an air leak and will likely seize it again.

 

[Help Wanted]

He probably has an air leak and will likely seize it again.

Um it never seized to begin with!!! Read my original post!! I tested it for air leak and no leaks!! I believe it is a combination of carb adjustment and a new clutch spring. Turns out you really know your stuff !! NOT!!!!

 

[bwalker]

Um it never seized to begin with!!! Read my original post!! I tested it for air leak and no leaks!! I believe it is a combination of carb adjustment and a new clutch spring. Turns out you really know your stuff !! NOT!!!!

You said it seized....and you didn't say you pressure and vac tested it.

You really don't know your stuff or you wouldn't be asking the basic questions you have.
Of course if you knew squat you wouldn't have bought a chicom chainsaw.

 

[pioneerguy600]

If it is not getting fuel on the idle circuit it will stall, an air leak usually still allows enough fuel for idle but it will be a high idle that can be masked out most times by richening up the H and L settings. I have worked on many air leaking saws that still ran but overly fast and lean sounding. A plugged up idle circuit in the carb will not allow the engine enough fuel to idle at all no matter where the screws are set.

 

[thompsoncustom]

There isn't a worse way to break in a two cycle motor than to do what you did.

he is 100% correct here, do some research on breaking in engines. idling is bad and load is what sets your rings.

a lot of people think they can idle it for awhile or a couple tanks and then put it under have load and it will be the same as running it under load to start with but it's not as studies have shown there is a window for proper break in and if you do it wrong then performance will be less even if it's not by a whole lot.