McCulloch Chain Saws

[Jethro 2t sniffer]

Carbs can do some strange things. I have a sdc44 that runs rather rich nose down but nose up quite lean and kinda think aww must be crank seals put that carb on another saw with good seals and awww what it was the bloody carb lol... in the rebuild pile you go Mr sdc.

The 2-10 I just gave a bath and fix up was running beautifully...5 days later a unrunable dog and is stripped again on the bench yay yay yay the bullfrog

 

[Jethro 2t sniffer]

Interesting stuff about the bars n chain factorys guys. It would be a nice place to work testing chains all day.

Who was the man Windsor? I can't find much about that company other than the obvious Blount bought them out. I really love my windsor speed tip and hard nose bars.

 

[BigBlue]

Sorry for the slow response time. Just what he mentioned above, if you can or can’t keep it going with a spray bottle it will help point you in a direction

Gotcha. Thanks to both of you.

Rob

 

[Brian Thacker]

You are right about the carbs. Have one of Ron's 125s that first started not running well and I cleaned the carb and kitted it. It seamed like you could set the low and it would be right on the money or just a little rich, you rev it a couple times and it would start running lean and quit. I thought well I must have not gotten it completely clean or had some stuff in the fuel line and sucked it back into the carb. I cleaned the carb again, put a brand new fuel line and filter on and washed out the tank. Got it back together and it acted the same way so I done a pressure and vacuum test and it had both seals leaking a little, but not much. So I changed the crank seals and tested it and all good. I also while in there put new points and condenser in. Started it up and same thing. I put my old fixed jet Tillison carb on it and it runs like a clock. Smooth as silk, no lean condition. I took a SDC carb I had taken off a parts saw and kitted it, this time I even removed the welch plugs and this carb was spotless under there. No Ron's old carb had the main one way valve and spring missing, mine was in good condition. I had to change out the throttle and choke shaft on the new carb to get it to hook up right. Put it all back together and same thing. Ron provided me with another SDC carb and hoping this will solve the problem. But for now it has me scratching my head.
I have had a couple carbs that if you turned them on there right side would go lean. I finally just richened them up a little and now OK. But thhe carb on Ron's saw you just keep chasing the lean till you can not richen it up any more and it quits. Very strange.

Brian

 

[mogulmasher]

Anyone have any tips on removing clutch on my Mac 790? There are very small threaded holes in clutch face. I put some screws in them and have my puller on it, but puller is really too wide for the spacing of those 2 holes. I'm afraid I'm gonna break something.

 

[heimannm]

mogul - I took a large, heavy washer and drilled a couple of holes to align with the threaded holes in the clutch, attach it to the clutch with long screws and use your puller on the O.D. of the heavy washer.

Brian - some times the throttle shaft and the bore where it passes through the body of the carburetor get worn, depending on the attitude of the saw, throttle position, or just how the shaft and bore slop together it can change the amount of air leaking through the carburetor.

Mark

 

[Brian Thacker]

Thank You Mark. I looked at that but briefly and it did not look like it had play in it but I think I will take another look at that. This is Ron's go to saw and we cut a lot of wood and you could very well be right. You have a lot more experience than I do. It has a lot of hours on it.

Brian

 

[mogulmasher]

Thanks Mark! Now that's off how do I remove the plate the pawls are mounted to? I gotta drive out one of the pins to replace the spring and pawl. Looks like the plate is one piece with the keyed center section.

 

[Jethro 2t sniffer]

You are right about the carbs. Have one of Ron's 125s that first started not running well and I cleaned the carb and kitted it. It seamed like you could set the low and it would be right on the money or just a little rich, you rev it a couple times and it would start running lean and quit. I thought well I must have not gotten it completely clean or had some stuff in the fuel line and sucked it back into the carb. I cleaned the carb again, put a brand new fuel line and filter on and washed out the tank. Got it back together and it acted the same way so I done a pressure and vacuum test and it had both seals leaking a little, but not much. So I changed the crank seals and tested it and all good. I also while in there put new points and condenser in. Started it up and same thing. I put my old fixed jet Tillison carb on it and it runs like a clock. Smooth as silk, no lean condition. I took a SDC carb I had taken off a parts saw and kitted it, this time I even removed the welch plugs and this carb was spotless under there. No Ron's old carb had the main one way valve and spring missing, mine was in good condition. I had to change out the throttle and choke shaft on the new carb to get it to hook up right. Put it all back together and same thing. Ron provided me with another SDC carb and hoping this will solve the problem. But for now it has me scratching my head.
I have had a couple carbs that if you turned them on there right side would go lean. I finally just richened them up a little and now OK. But thhe carb on Ron's saw you just keep chasing the lean till you can not richen it up any more and it quits. Very strange.

Brian

The zama on my 800 has a very similar thing the high is fine but the low is dog rich so wind in the screw till nice and touch the throttle and then would go way lean lol so richin it up again yup good and after 10 secs start getting richer n richer... around n around for 10 mins ahhh screw this. I have a sdc44 on it now until the zama kit arrives. The 44 as you guys know does not fit the rubber needle boot thingy it could be modified to fit but then the zama won't fit so I just tape up the hole in the air box in the meantime. Ain't it strange how a carb goes from running perfect then a week later it's terrible

Anyone rebuilt the zama off an 800 are they ok to do?

Good to see you here Brian hope you get that 125 going good again I/we are missing you n Rons tales and exploits on the end of yellow saws every Sunday morning with a coffee

 

[Brian Thacker]

We will be back cutting soon. Most of us do not cut during the summer. I have had many things to get done and don't seam to be putting much of a dent in them. Ron purchased a new tractor and among other duties and chores around the house has been getting it ready to work hauling logs. On top of all this it has been about the hottest summer on record and I am getting old and cannot take the heat as well as I used to. I am glad that you enjoy Ron and Is' exploits or sometimes miss adventures. We both enjoy cutting with our old MACs. Ron is the mastermind, I am just a sidekick he brings along for comic relief.

The Zama carbs are not much different than the Walbros to rebuild. Sounds like we are chasing the same horse. The same way Ron's saw is acting. I would not have guessed that it would go from a good running saw to this in the short time it did either. But I am in hopes this will fix his. I want to get it back to him because cutting weather is upon us and will need it soon.

Brian

 

[Jethro 2t sniffer]

We will be back cutting soon. Most of us do not cut during the summer. I have had many things to get done and don't seam to be putting much of a dent in them. Ron purchased a new tractor and among other duties and chores around the house has been getting it ready to work hauling logs. On top of all this it has been about the hottest summer on record and I am getting old and cannot take the heat as well as I used to. I am glad that you enjoy Ron and Is' exploits or sometimes miss adventures. We both enjoy cutting with our old MACs. Ron is the mastermind, I am just a sidekick he brings along for comic relief.

The Zama carbs are not much different than the Walbros to rebuild. Sounds like we are chasing the same horse. The same way Ron's saw is acting. I would not have guessed that it would go from a good running saw to this in the short time it did either. But I am in hopes this will fix his. I want to get it back to him because cutting weather is upon us and will need it soon.

Brian

Very much enjoy it and Ron writes a good story too. Good to hear you boys are getting back into it.

I get the too hot to cut thing I got heat stroke last year cutting in 30 plus and yeah nah never again.

 

[fossil]

Thank You Mark. I looked at that but briefly and it did not look like it had play in it but I think I will take another look at that. This is Ron's go to saw and we cut a lot of wood and you could very well be right. You have a lot more experience than I do. It has a lot of hours on it.

Brian

Hi Brian,
If it's an SDC 20 or any other SDC that has two welch plugs on the metering side, pop out the small welch plug and change the capillary screen. Even if it looks OK, just change it. If that is the least bit dirty (varnish build up) or damaged which is very hard to see, it can cause a low fuel flow on the high side. The little clip that holds the screen in will likely fly away but most kits include the screen and the clip.
It's worth your time and has worked for me.
I use a small slot hobby screwdriver to pry the clip out.

 

[fossil]

Very much enjoy it and Ron writes a good story too. Good to hear you boys are getting back into it.

+1 on that.

I had a really good laugh when you two were considering going to Randy's Tennessee GTG and Ron said he really didn't have anything interesting to bring except Brian.

 

[Jethro 2t sniffer]

+1 on that.

I had a really good laugh when you two were considering going to Randy's Tennessee GTG and Ron said he really didn't have anything interesting to bring except Brian.

Haha that's classic

 

[fossil]

Interesting stuff about the bars n chain factorys guys. It would be a nice place to work testing chains all day.

Who was the man Windsor? I can't find much about that company other than the obvious Blount bought them out. I really love my windsor speed tip and hard nose bars.

Some info here on Windsor

http://www.acresinternet.com/cscc.n...d2e506131fdde44688256bf6000fd261?OpenDocument

 

[Brian Thacker]

Hi Brian,
If it's an SDC 20 or any other SDC that has two welch plugs on the metering side, pop out the small welch plug and change the capillary screen. Even if it looks OK, just change it. If that is the least bit dirty (varnish build up) or damaged which is very hard to see, it can cause a low fuel flow on the high side. The little clip that holds the screen in will likely fly away but most kits include the screen and the clip.
It's worth your time and has worked for me.
I use a small slot hobby screwdriver to pry the clip out.

Tim, The original carb that was on the saw was missing the screen all to gather, including the clip. The second carb has the screen in place and went thru the ultrasonic cleaner and is clean as it gets The carb was new when I got it. Very clean. I was surprised the old carb was missing the screen. I did not think they would run proper without that screen. I thought it was to atomize the fuel to help keep the fuel in vapor. The second carb I had to switch the throttle shaft and use the shaft out of the old carb because of how the throttle connects. The SDC I used was from a 10-10 pro. It kind of bewilders me that a 54cc 10-10 Pro would have the same size carb as a SP125c. I bet they used that carb to increase torque on the 125 and to make the 10-10 scream. I wonder how a 125 would act if a man could find a carb that is about 2mm larger and fit that bolt pattern? Any way I bet that throttle shaft is worn. Ron gave me 2 SDC carbs he had to try. They look clean. I am going to kit them and see what they do. Will let you all know the outcome.

By the way I am a very dull person and not very interesting.

Brian

 

[Jethro 2t sniffer]

Some info here on Windsor

http://www.acresinternet.com/cscc.n...d2e506131fdde44688256bf6000fd261?OpenDocument

Exactly what I was after thank you very much

 

[fossil]

By the way I am a very dull person and not very interesting.

Brian

It took me many years to realize looking from the inside out is very different from looking from the outside in, if you get what I mean

I don't find you the least bit dull or uninteresting.

 

[Jethro 2t sniffer]

It took me many years to realize looking from the inside out is very different from looking from the outside in, if you get what I mean

I don't find you the least bit dull or uninteresting.

Your very interesting Brian and have a great head for engines of all sorts

 

[Brian Thacker]

Thank You but I am Just an old hack.

Brian