McCulloch Chain Saws

[PogoInTheWoods]

place some oil at that little hole where the carb gasket sits at the carb mount, is that right?

Yes.

And then what do you mean by barb at the handle?

The pulse hose connection stub under the carb mount that feeds the little hole.

 

[Yokosukadweller]

Yes.

The pulse hose connection stub under the carb mount that feeds the little hole.

Right, I just checked. The small hole to impulse line under carb both pulls and spits oil when I pull the rope. So there is action, but the impulse line is rotten so I will replace it. And a carb rebuild is probably in order anyway.

 

[vinnywv]

Any tips on prepping the cylinder. I have never prepped a new one so to speak lol. Warm water and mild dish saop with clean white cloth. then blow out with air then check with dry white cloth?

All i did was clean it out. There was a bit of blue clay in it left over. Then wiped it all down inside with 2 stroke oil. Used a bit more when i assembled it. It came from a member here but had never been used.

 

[Yokosukadweller]

Opening the walbro carb I find some dirt which I remove. Then I notice there simply is NO Welch plugs in it. I think there's supposed to be two -one smaller and one larger. The smaller should have a valve and assembly beneath it.

At the same time I discover that my kit doesn't seem to have such valves. Only the plugs. I took a picture. No valve and seat assy right? I suppose these are important isn't it. So yes. I'm kinda stuck for now. Any thoughts ?

 

[Maintenance supervisor]

These are the welch plugs as pressed in,
I believe that you might be missing a spring ?

 

[Yokosukadweller]

View attachment 922677
These are the welch plugs as pressed in,
I believe that you might be missing a spring ?

I do have the spring. Not in the set but under the metering lever there was one. Thanks for pointing out there are already plugs there. I had not seen it. I'll try removing these plugs then.

 

[Maintenance supervisor]

this is whats underneath.
Check valve kit for sdc walbro.

 

[Maintenance supervisor]

I do have the spring. Not in the set but under the metering lever there was one. Thanks for pointing out there are already plugs there. I had not seen it. I'll try removing these plugs then.

Use caution when removing the plugs as you can damage the tiny passageways or holes underneath.

 

[Yokosukadweller]

View attachment 922687this is whats underneath. View attachment 922688
Check valve kit for sdc walbro.

Thank you for the awesome help. I got it opened but I do not have the valve replacement. So am just cleaning it and replacing the plugs. Then after cleaning the other areas my plan is to reseat the metering system, replace the cover gasket on metering side and the fuel pump diaphragm on the other side and put things back together. The carb is reasonably clean now. Do I need to check anything else? I don't really know what doing tbh...

 

[Maintenance supervisor]

Under the screen should be a tan or black disc that operates the high speed check valve.
Hold the carburetor choke open and shine light down the throat you should not see clear light.

 

[Yokosukadweller]

View attachment 922692
Under the screen should be a tan or black disc that operates the high speed check valve.
Hold the carburetor choke open and shine light down the throat you should not see clear light.

No light coming through. I did spray a bit of carb cleaner in there and hope I haven't damaged the valve since I don't have replacement parts on hand. But so far so good. One issue I have is the new valve plug seems to be a bit too large in dia for the hole. I'll get a metal file and work it a smidgen smaller but not too small.

 

[Yokosukadweller]

Finished. Let's see if it helps the saw run. I did find some white gunk in the needle hole and removed that. I did replace those Welch plugs. That probably wasn't necessary but no problem. Also replaced the gaskets seen in front of the carb. Not all but those ones looked a bit tired.

Next time I will know more and feel more comfortable working with chainsaw carburetors especially if I can start buying old saws cheap to restore them coz that's a lot of fun.


Thanks a lot to everyone who gave important guidance along the way. Cheers.

 

[Maintenance supervisor]

So I'm having a weird time with my ProMac55, it obviously had a bad PTO seal which I replaced with a 6119 skf.
The flywheel seal looked great but looked a little high so I set it a little deeper in the bore.
The saw idles runs and sounds good , when flipping it side to side pto/clutch theres no perceptible change in rpm speed , but when I let it run on the oil tank cover then briskly set it on its belly it shuts off? Like idles down and dies. Restarts fine and everything but the front down to handle level it doesn't like and it doesn't shut off if I go slow with the movement.

Any suggestions are welcome.

 

[edju1958]

I think you did awesome on your first carb rebuild! My first carb rebuild was a disaster,Lol.Of course I didn't have any help like you had here.Great bunch of guys to help you out.I told you so,Lol.

 

[heimannm]

The only one that is mine is the non-working SP125.







The CP125 belongs to Sawfun, I put this one together from a tote of parts he sent with me a couple of years ago and took it along to the PNW GTG this year only to have it not run. When I finally got around to investigating the problem I found the intake boot was not properly seated on the saw. I wish I had looked more closely when I had the carburetor off in Oregon as it was pretty obvious when I had it apart in my shop today.

The Super 797 belongs to a local fellow. It was not running when he dropped it off but a carburetor kit and new carburetor gasket cured that. Somewhere along the way the oil tank had been been changed out with one from a 1-7X type saws without the automatic oiler so I replaced that one with a correct one providing the automatic oiler again.

The SP125 came to me this week but will need a lot of TLC to make it a runner again.

Mark

 

[edju1958]

I finally got aropund to my little Eager Beaver 2.1.The manual oiler stopped working again.I pulled the front cover off & found the cuilprit - kinks in the line.I put a new line in that was scavenged from another saw.It seems the line I was using previously was a bit too small in diameter & this allowed the tank to leak if cutting on it's side or when the tank was full at a steep upward angle.This little saw gave me a workout.I must've put the cover on & off about 8 times before it'd finally pump oil without stopping.It seemed as soon as I put the cover back on it'd pinch the oil line somehow.Bob J.told me a couple yrs.ago when I worked on this saw that I had to coil the line.I don't know how I was supposed to coil it & hurry up & shove it in that tiny cavity.I just cut the line short so there was no excess & then put it together.

I got the saw put all back together & went to fire it up & no go.The saw had no spark.I put a new plug in & it fired right up. I like working on saws,but not these little turds.

 

[heimannm]

MS - when you figure it out let us all know as I have a friend that I spoke with today that has two 10 Series saws doing the same thing.

Does it need throttle to get it started again? If so, it may be flooding due to excess fuel puddling in the crankcase. This was an ongoing problem for the older reed valve saws and McCulloch was continuously working on ways to minimize the problem. I haven't had that issue with a 10 Series saws myself so I don't have assistance to offer.

Mark

 

[Yokosukadweller]

I think you did awesoI me on your first carb rebuild! My first carb rebuild was a disaster,Lol.Of course I didn't have any help like you had here.Great bunch of guys to help you out.I told you so,Lol.

That's right @edju1958 I was rescued here. But then what happened was I put the carb on, pulled once and the saw started immediately. It was stuck on high revs, so I screwed the idle screw out. I must have screwed too much because after 25 seconds the saw stalled.

I went in raising my arms in victory to my wife, who just looked puzzled. Anyway, declared victory too early. I was not able to start the saw again yesterday.

Basically it floods the engine now. When pulling from time to time I can hear hissing out of the top of the carb, and it will give one explosion here and there, but not start.

It may be a faulty impulse line (got a Stihl one on order), but that doesn't chime with the compression that I feel is there, and the vacuum is also ok.

I may have made some mistake with the carb rebuild. I want to take a look at the metering lever, maybe that little metal seesaw pulls the needle too much which can cause the flooding....i am not sure but imagine this could be the case. I do not have a gauge so not sure what the right height is. Anyway, i'll keep at it and the lesson continues I guess.

 

[ozziechainsaw]

Hi Guys,

Just wanting some advice. I have a couple of SP81 saws that need some carby overhaul kits put through them, but I am not sure of which rebuild kits I should be looking for.

Can someone help ?

My SP81 saws have the single mixture screw type carby on them.

Cheers

Justin

 

[Yokosukadweller]

Ho Ozzie, if the carb is a Walbro SDC 18 like mine, the SDC-10 kits that are available on ebay fit. Others might know more...