XL1 Revving up when cold

[lobo]

Hi,

New to chainsaws in general and have acquired an XL1 chainsaw as a birthday present. At the time of receipt the saw was not running. I bought a new coil for it and is running ok (i think). 

My Questions is:

When I start it from cold, I have to keep the choke pulled out full until she gradually warms up. Otherwise she will ramp up speed to the point where the saw is revving at about 3/4 throttle and the chain is spinning like mad. Once its warm, I can push the choke in and she idols OK.

Is this normal for my XL1 to rev like this when cold? 

thanks,

LOBO

[lubener]

Could be normal depending on the temperature. Might want to check the fuel filter since fuel demands are highest when cold. Verify the use of fresh gas. Since the engine runs good when warm, I doubt the carb needs tweeking.

[lobo]

Thanks for your reply. Gas is fresh (2 weeks). Whats the best way to check the fuel filter? Visually it looks okay, but I know the saw is old. Maybe I will just replace it anyway.. it's like a $3.00 part...

One other thing I notice is that after the saw is warm and I make a cut, it takes a little while for the engine to ramp down, and return to idle. Maybe 6.0-6.5 seconds. All the while, the chain is spinning. Is this normal? From what I have seen with other saws on youtube, they seem to return to idol in around 2-3 sec.

What could be the cause of this?

[lubener]

My saws have a filter on the end of the pickup tubing in the tank. I fish it out of the tank, remove it from the line and blow thru it. You cannot judge it by its appearance. As far as you idle issue, I would check for binding throttle linkage or carb.

[lobo]

Thanks for the filter testing tip. The throttle does not bind at any position. What else could it be?

[lubener]

The only other thing I can think of is the actual idle speed screw on the carb is SLIGHTLY out of adjustment.

[sweepleader]

I don't have any experience directly with your model but in theory if there were a vacuum leak on the engine side of the carb, when you pulled the choke and made the mixture excessively rich for starting, a leak might lean the mix once the engine started and allow it to race as you describe. At least in my mind it would be possible. I would go looking for a vacuum leak at the carb base or somewhere there abouts. Good luck.

[lobo]

Dec 9, 2013 10:43:58 GMT -5 sweepleader said:

I don't have any experience directly with your model but in theory if there were a vacuum leak on the engine side of the carb, when you pulled the choke and made the mixture excessively rich for starting, a leak might lean the mix once the engine started and allow it to race as you describe. At least in my mind it would be possible. I would go looking for a vacuum leak at the carb base or somewhere there abouts. Good luck.

Hi Sweepleader,

The engine does not race while cold when the choke is on (pulled out). Only when engine is cold and I push the choke half in or full in (half off or full off). I should also note that while the choke is pulled out full there isn't any response from the throttle trigger. However when I Push the choke in, the trigger throttle does become more responsive but then the saw is already revving at like 1/2 throttle. 

The whole starting thing is not such a huge deal to me at the moment. BUT the real issue of my chainsaw is how long it takes for the engine to rev back down to idle. I think there is a high potential for an accident as you have to be really careful of the saw bar whereabouts because the chain still spins for about 7 seconds after a cut.


I do think the 2 issues are somehow linked, but I am not sure where to begin the troubleshooting. I did remove and rebuilt the carb. Now that I think about it, I had to make a couple gaskets between the carb and intake spacer, & between intake spacer and the pyramid valve thing. I wonder if this is where the problem lies.... 


Thanks,

Lobo

[sweepleader]

While reading your response it occurred to me that with a vacuum leak you might have to set the carb rich (compared to no leak) to get the mixture the engine sees to be correct. That might result in a lean mix, high speed with no throttle control over the air coming through the leak when you try to go to idle. There would likely be poor power but you would not notice since the saw would not be in the cut. It would seem to me that if this were to be happening, the leak would have to be on the carb side of the reeds. It could be a gasket or a component with a hole.

I might try leaning out the idle mix to where the engine dies and see if that changes the high speed thing. You need to have a lot of air to the engine if it is going to run fast. If you have uncontrolled air (through a leak and not through the throttle) to the engine and enough fuel from the idle circuit, I can see no load high speeds till the fuel coating all the internal engine parts combined with the idle fuel runs out.

All this is conjecture of course, I never had this happen exactly. I HAVE run across a lot of vacuum leak troubles with many various symptoms on larger engines.

Very interested to learn what you find.

[lobo]

Hey,

Thanks for your response. I realized I had made a big mistake before posting my original message. My tank was low on gasoline and I believe it was just not getting enough gas and that's why it was racing. (lean mixture). haha I did not notice this until I looked at the saw  a week later and noticed I had very little gas in the tank. After I refilled the tank it was warming up ok... oops...

But I still have the problem where after a cut the chain does not want to stop spinning. I had one situation where once the clutch engaged, it would not disengage at all. I tried lowering the idle until the saw was running really slowly and would die but this still wouldn't stop it. Then I noticed that when it's idling and I pressed the bar against some wood the chain would stop spinning but immediately spun when I removed the saw. Attached is a pic of my clutch. Is it possible for these types of clutches to stick? Its not the spring type. After I noticed it wouldn't disengage, I took it apart to inspect the clutch but everything seems ok. (to be honest I don't really know what to look for except for obvious signs of damage, wear etc. It had oil inside it which didn't think there should be (from the auto chain oiler maybe?). I checked for cracks etc in the clutch which may make it easier for it to engage. Any ideas? Maybe it's just old? To me these types of clutches seem like they should lake damn near forever because of their design. I must be missing something.

I wanted to remove the entire clutch but I couldn't get it off. it seem to be frozen on the crank. Any tricks to removing it?


Thanks,
Lobo

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