MCCULLOCH The official McCulloch thread

Bigmac · Dec 22, 2019

Frank bierce said:
It has a Tillotson hs124 on it.

I’ve been wanting to try the larger Venturi 10 series carburetor and converting it for the 125, it’s fairly easy to adapt

Steve · Dec 22, 2019

Bigmac said:
I’ve been wanting to try the larger Venturi 10 series carburetor and converting it for the 125, it’s fairly easy to adapt

SDC18?

Bigmac · Dec 22, 2019

Steve said:
SDC18?

To be honest Steve idk, I know virtually nothing about 10 series saws! I just have seen that some have a larger Venturi and have the idle screw on the carburetor, you have to drill the impulse Barb and put a fitting in the top, on some you have to change the inlet nipple as well and modify the choke arm.But I have no idea what model is the best to do that with

Steve · Dec 22, 2019

Bigmac said:
To be honest Steve idk, I know virtually nothing about 10 series saws! I just have seen that some have a larger Venturi and have the idle screw on the carburetor, you have to drill the impulse Barb and put a fitting in the top, on some you have to change the inlet nipple as well and modify the choke arm.But I have no idea what model is the best to do that with

Oh, then it wont be the sdc18. That has the large venturi but need an external idle screw. I think i have one of those carbs with the internal idle screw. Ill check here in a bit

fossil · Dec 22, 2019

Steve said:
SDC18?

Bigmac said:
To be honest Steve idk, I know virtually nothing about 10 series saws! I just have seen that some have a larger Venturi and have the idle screw on the carburetor, you have to drill the impulse Barb and put a fitting in the top, on some you have to change the inlet nipple as well and modify the choke arm.But I have no idea what model is the best to do that with

The SDC 20 is the carb that came in the CP125 and I believe on some earlier SP's. Hi and low are adjustable and the idle speed screw is on the side.

I always though it might be worth a try to adapt a WB off a Super 650 or 750 Homelite or maybe an HL

Bigmac · Dec 22, 2019

fossil said:
The SDC 20 is the carb that came in the CP125 and I believe on some earlier SP's. Hi and low are adjustable and the idle speed screw is on the side.

I always though it might be worth a try to adapt a WB off a Super 650 or 750 Homelite or maybe an HL

You are correct on the sdc20, it’s a good carb, but hard to find. Some of the 10 series saws had larger carbs than the 125, and are available!

I just got done doing the wb swap in the box and v4 reeds, I test fit the 750 carb before starting

p61 western · Dec 22, 2019

Bigmac said:
You are correct on the sdc20, it’s a good carb, but hard to find. Some of the 10 series saws had larger carbs than the 125, and are available!

I just got done doing the wb swap in the box and v4 reeds, I test fit the 750 carb before starting View attachment 214270

Now you say something.

Bigmac · Dec 22, 2019

p61 western said:
Now you say something.

Ya, mark had mentioned it not that long ago, but I hadn’t seen any pics, then I saw bellhopper on YouTube do the swap like 2 weeks ago, showed some pics and the saw running after, with a port job, looks good. I would like to try, just to know! It’s not much bigger.

but I hear ya...sorry

p61 western · Dec 23, 2019

Bigmac said:
Ya, mark had mentioned it not that long ago, but I hadn’t seen any pics, then I saw bellhopper on YouTube do the swap like 2 weeks ago, showed some pics and the saw running after, with a port job, looks good. I would like to try, just to know! It’s not much bigger.

but I hear ya...sorry

Lmao zero sorry needed. It is something cool to know though for sure.

jacob j. · Dec 23, 2019

Saw-King told me years ago that some of the carbs for the smaller saws can be used but the jets need to be drilled depending on which carb you're converting.

Some of those carbs don't deliver as much fuel under load.

Bigmac · Dec 23, 2019

jacob j. said:
Saw-King told me years ago that some of the carbs for the smaller saws can be used but the jets need to be drilled depending on which carb you're converting.

Some of those carbs don't deliver as much fuel under load.

I was concerned about that too, I don’t know what carbs are the best to convert? Mark was happy with his, but I don’t know the model. It would be interesting to try, on my motorcycles carbs the larger engine usually needs smaller jets to preform correctly over the smaller engine with the same carb, the larger engine pulls more fuel out of the jet, but these pumper carbs are different for sure

Al Smith · Dec 23, 2019

jacob j. said:
Saw-King told me years ago that some of the carbs for the smaller saws can be used but the jets need to be drilled depending on which carb you're converting.

Some of those carbs don't deliver as much fuel under load.

Rich knows his stuff no doubt .That's where the saw in my avatar came from .I sent him a picture after I restored it .

heimannm · Dec 27, 2019

It seems to me someone was asking about the McCulloch 170 welder leads a few pages back. I finally remembered to take some photos.

First up, the receptacles on the welder:

Notice the air/vacuum connections adjacent to the other receptacle.

One of the plugs, notice the two air/vacuum lines tucked in behind the plug. There is a thumb operated valve on the electrode holder to allow remote control of the throttle while operating the welder.

The other plug.

That little "canister" looking device next to the carburetor is a cylinder connected to the air/vacuum lines that are in turn connected to the crankcase. I expect there must be a duckbill or check valve in the circuit somewhere but I haven't torn in to one enough to know exactly how they work.

Mark

heimannm · Dec 27, 2019

I used the SDC18 off a CP70 on one of my SP125's with very noticeable improvements in performance using the jets just as they were. I did have to grind a little in the air box to make way for the adjustment screw and for some reason the choke would not connect but I don't remember the particulars. I only use this saw a few times a year (Baraboo, etc.) so removing the AF cover and filter to start the saw is not a big deal. A clever fellow would also notice there is no idle speed adjust screw...in this case the throttle linkage just happened to stop the throttle in exactly the right spot to provide a good idle. Always better to be lucky that to be good.

The SDC18 was not equipped with the fitting for the external impulse line but I was able to modify the fuel pump cover and found a suitable donor nipple off some scrap carburetor I had laying around. The cover was equipped with a boss in the spot where the impulse fitting was to connect.

Mark

fossil · Dec 27, 2019

@heimannm

I have to ask. Is the caterpillar MAC tractor heading to the museum?

PS, My SP80 or whatever it is has an SDC 18 on it. Not sure if that's a sub or original.

heimannm · Dec 27, 2019

I put the Struck rubber track kit on a few weeks ago. For now, I will keep this in the shop at home and use it to clear the driveway when it starts snowing next year.

Mark

Frank bierce · Dec 28, 2019

Picked these up yesterday. Mac 895, and a 1-75. 895 starts on a prime, but dies quickly. 1-75 has some light mag rot under filter cover, and has no spark. Will likely need to clean up the points.

sawfun · Dec 28, 2019

Frank bierce said:
Picked these up yesterday. Mac 895, and a 1-75. 895 starts on a prime, but dies quickly. 1-75 has some light mag rot under filter cover, and has no spark. Will likely need to clean up the points.
View attachment 215436

You'll like that 895, though with a few more feet of bar.

Frank bierce · Dec 28, 2019

sawfun said:
You'll like that 895, though with a few more feet of bar.

Yeah, I agree. I’ll have to come up with a bigger bar at some point.

Bigmac · Dec 28, 2019

Frank bierce said:
Yeah, I agree. I’ll have to come up with a bigger bar at some point.

What Mac bars do you have?

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