371XP will idle, nothing else.

[RiverLogger]

I have my dads 371XP and it will start and idle, but as soon as you hit the throttle it bogs and dies out. If you can pull the choke quick enough it will pick back up and idle again. I took the carb off and completely went through it, put new fuel lines throughout and a new plug. The carb was really nasty inside. Full of varnish and the likes. There was some evidence of rust too. I'm pretty sure I got the carb pretty clean. What do you all think?

RL

 

[Roanoker494]

Sounds like there could be some of that varnish stuck inside the jets, need to run the carb through an ultrasonic cleaner or allow it to soak in a mild carb cleaner and gas solution for a few days.

EDIT:
Before you go tearing that carb back down, where do you have the H&L needles set? May want to run them all the way down and set them back out to 1.25 turns, that should be good enough to run. Not only will that return the carb to "factory" settings the needles will poke out any crud that may be stuck in the jets.

 

[RiverLogger]

H&L needles are right back where they were when I started. I'll check them again tomorrow to make sure I'm atleast 1 1/4 turns out.

 

[SilverKing]

metering lever pulling the float open enough?

 

[PARTSWOODCHUCK]

Did you change all of the gaskets? Ethanol chews them up pretty quick

 

[fearofpavement]

Probably: A fuel issue.
Possibly: timing off.

 

[SkippyKtm]

You may need to use a USC (ultrasonic cleaner) to really get the carb clean. If you have access to another 371/372, I'd temporarily swap carbs to see if the problem goes away.

 

[RiverLogger]

If you have access to another 371/372, I'd temporarily swap carbs to see if the problem goes away.

I do have a 372XPW. I'll give this a shot tonight and see what happens. Great idea. I did change all gaskets and fuel lines.

 

[RiverLogger]

Okay, so I took the H&L all the way out made sure to clean really good and screwed them all the way back in and then unscrewed 1 1/4 turn each. The saw is super hard to start(30-40 pulls) and when it did start it ran much better. Not perfect, but much better. I didn't switch the carbs yet, but will try to tonight and report back. Why is is so hard starting?

RL

 

[PARTSWOODCHUCK]

The diaphram in the carb is more than likely smoked from ethanol, very, very common nowadays

 

[RiverLogger]

I took the carb back off and cleaned everything really, really good. New gaskets all around and put it back together. Set H&L to 1 1/4 turns and it popped 4th pull. After messing with it for a few minutes I got her to run really good and adjusted so she idles and revs real nice. I do have another question though. The high is fairly easy to set, but the low I'm not sure about because you can manipulate this adjustment with the idle setting. How do you know you have the low set correctly?

Thanks for all the help so far guys.

RL

 

[w8ye]

I try to set the low speed mixture screw as lean as possible and the chainsaw will still accelerate from from idle.

Too lean and they stumble or quit.

Also with the idle mixture set too lean and the idle speed screw set a certain way, and the engine will not go completely down to idle right away but will be at a high idle and slowly go down to the lowest idle.

The idle speed should be set just below the point that the chain moves.

 

[RiverLogger]

Well from the sounds of the post above, I have it set right then. It idles great, accelerates great and I have it set so it 4 strokes until you work it pretty good in the cut. I'm waiting for a tach to get the H setting perfect.

Thanks alot Arboristsiters!!!!

 

[greg409]

Well from the sounds of the post above, I have it set right then. It idles great, accelerates great and I have it set so it 4 strokes until you work it pretty good in the cut. I'm waiting for a tach to get the H setting perfect.

Thanks alot Arboristsiters!!!!

The tach is fun, but I'd make sure it 4strokes until load, I'd rather run a little rich than lean any day.

luck,greg