Mcculloch Super Pro 125C crazy idle!

[Ghostbandido]

Hi everyone,
my name Jerry and although I'm new to this forum, I've been reading and learning about chainsaws for about 6 years with all the wealth of knowledge everyone brings here. I've been collecting chainsaws for about 7 years and own about 12, from a small arbor Echo,a Stihl 066,a McCulloch Pro Mac 850 Super, and the final one...Mcculloch Super Pro 125C.
It's in fantastic condition. It started right up, but then died out. So I changed the spark plug, and I reseated the H and L and brought them out to to 1. I started it right up and it screamed ridiculously and I hit the kill switch, I thought the old fella was going to blowup. I opened the H and L to about 1/4 more and it did the same.
I remember the H and L were seriously pulled out to about 6 turns on the H and about 3 on the idle screw. Maybe that is where it needs to be. I am seriously timid to mess with it again until I know what's the right way to set this beast. Any advice for a newbie is appreciated.

Thank you kindly

 

[Bill G]

Sounds like an air leak

 

[stihlaficionado]

Hi everyone,
my name Jerry and although I'm new to this forum, I've been reading and learning about chainsaws for about 6 years with all the wealth of knowledge everyone brings here. I've been collecting chainsaws for about 7 years and own about 12, from a small arbor Echo,a Stihl 066,a McCulloch Pro Mac 850 Super, and the final one...Mcculloch Super Pro 125C.
It's in fantastic condition. It started right up, but then died out. So I changed the spark plug, and I reseated the H and L and brought them out to to 1. I started it right up and it screamed ridiculously and I hit the kill switch, I thought the old fella was going to blowup. I opened the H and L to about 1/4 more and it did the same.
I remember the H and L were seriously pulled out to about 6 turns on the H and about 3 on the idle screw. Maybe that is where it needs to be. I am seriously timid to mess with it again until I know what's the right way to set this beast. Any advice for a newbie is appreciated.

Thank you kindly

May want to post this in the Chainsaw forum, you'll get more views.

There are also ChainSaw Stickies(subforms) on various brands

Welcome to AS

 

[buzz sawyer]

Is the idle speed screw set out too far or fast idle stuck in? Agree with a possible air leak. Mine starts fine and idles a little fast, then settles down once it's warmed up. I need to check it as well. There are a lot of sealing surfaces on the intake and oil pump as well as the crank seals.

 

[Ghostbandido]

Thanks for your response.
The idle screw and the low jet screw are all that this one has. I just went ahead and seated them.
I just don't know how far to bring them out. I thought like most other saws around 1 1/4 -1 1/2, but it started screaming.

 

[buzz sawyer]

You should have an idle speed screw. Can you post a pic of the carb? Or look into the carb throat to see if the throttle plate is closed - or maybe missing???. if it's there and closed, you must have an air leak.

 

[Garrett Lee]

Sounds like an air leak

Most definitely is an air leak

 

[Jay Hansen]

For a leak that severe I'd look first at the boot between the carb and the reed block and next at the impulse line.

 

[Busmech]

The way I read this is you turned the idle screw all the way in, That would give you a very fast idle. Turn the idle screw out 3 to 4 turns if it is still fast turn it out some more, if it wont idle turn it in till it does.

 

[heimannm]

I have a good supply of aftermarket boots to fit the large frame CP/SP saws like your SP125.

Mark

 

[buzz sawyer]

I have a good supply of aftermarket boots to fit the large frame CP/SP saws like your SP125.

Mark

How do you like them? I saved a couple used OEMs in good cond. but wondered if the aftermarket were as good or better.

 

[heimannm]

I am very happy with the ones I have used, only two or three saws for me so far but one saw in particular that I've been using for a couple of years, they stay very supple.

I used one on the CP125 for Sawfun and that's been at least three years now.

Mark

 

[uswrtd52]

Thanks for your response.
The idle screw and the low jet screw are all that this one has. I just went ahead and seated them.
I just don't know how far to bring them out. I thought like most other saws around 1 1/4 -1 1/2, but it started screaming.

Which Carb? I started at 1.5 turns on my screws, but I believe one would have been better. Left is the Low Speed mixture, Right is High. Above them should be the idle screw. Turn the idle screw in for faster idle. Set idle, then move L screw in, then out to find optimum. High speed, turn in until it smooths out.