McCulloch Chain Saws

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I got a question is there any suggested fuel line and pulse line replacement suggestions for a pro mac 850? expecially the fuel line it takes some funky turns in a short distance.thanks
What Carb? Walbro SDC or Zama C2? Impulse lines are not hard to find. If its trying to suck itself shut slide a small spring into it. Both Mark and I have NOS impulse lines. I make conversion fuel line kits for the SDC setups also.
 
There are a number of options for the 10 Series fuel lines, several aftermarket are available but try to find a name you recognize, Stens, Rotary, etc.

Max (Knightmax) has some aftermarket kits on eBay that utilize a smaller diameter Tygon fuel line and a new fitting for the carburetor.

I have some aftermarket kits with Tygon and a grommet in the tank.

The Duke has some AM fuel lines that work on many saws but may need a few wraps of teflon tape where they pass through the tank to insure a positive seal.

You can find 69598 (pulse line) on eBay for ridiculous prices, you can often reuse the old pulse line, or I have both NOS and good used one available.

Mark
 
I was able to find a parts list for the 850 super, I assume that most of the parts cross over. Is this a error on my part? or is it a good parts list to use when I need something.
 
The Super 850 is really a PM800 saw and while many parts interchange (fuel and impulse lines for example) there are many that do not. The 800 family (PM805, 800, Super 850, DE80, and PM8200) have a different flywheel, different flywheel housing/starter, different rear shroud, different AF cover, different muffler, different clutch cover/brake housing, different lower brace...

Mark
 
Got to run some Mac's today. Bucking up the last of two log piles that came via knuckle boom truck. Ran my super 10-10 and the 10-10 light weight.
I had never done the final setting of the carb on the super but got to it today. It was rich and doggy. Better power now but need to address the b&c starts.to cut boat wood on larger logs.
The lightweight needs some love. It's a strong runner , but wants to die if left to idle too long and is a bear to restart. Tank gasket leaking also.
Still good to run them and learn what they need to be top notch.
 
What Carb? Walbro SDC or Zama C2? Impulse lines are not hard to find. If its trying to suck itself shut slide a small spring into it. Both Mark and I have NOS impulse lines. I make conversion fuel line kits for the SDC setups also.
they pulse line has a spring in it already but it is sticky and wierd feeling but I think it has no holes in it but I would like to change it out anyway. and what ever on the fuel line as long as it does not leak at the tank gromet. could I get some contact info. so we can get some parts ordered. thanks dave
 
Yup and FYI to all, It is a link to the McCulloch Vintage Chainsaws folks group.
Was supposed to be a pic of an old Mac go cart of some sorts but I'm as good with tech as I am rocket science, brain surgery or understanding women.
 
they pulse line has a spring in it already but it is sticky and wierd feeling but I think it has no holes in it but I would like to change it out anyway. and what ever on the fuel line as long as it does not leak at the tank gromet. could I get some contact info. so we can get some parts ordered. thanks dave
Meaasge Sent
 
Was supposed to be a pic of an old Mac go cart of some sorts but I'm as good with tech as I am rocket science, brain surgery or understanding women.
Yes it is, But the bigger deal of my mentioning the FB Mac group where it is found is that if one wants help over there too, they can ask questions there as well as here,
 
The D-30 and D-36 were the two "center pull" models. They look like they would be convenient, start with either hand, but in reality they are pretty awkward to start. You have to hold the choke closed by pressing the button with the thumb on your right hand and pull with the left...having the starter in the center does not enhance the process in any way.

They also incorporated the "Lubri-Mac" system that scavenged "unburnt fuel and heavy crankcase residue" from the bottom of the crankcase and directed it to the bar for lubrication. They had no separate oil tank for bar oil. McCulloch came out with a retrofit kit that added a plate/divider in the front of the fuel tank and a new fuel tank cover complete with a manual oil pump. It was necessary to drill out a passage in the back of the bar pad to allow the manual oiler to function. You can see the manual oil pump on the front of this 1-40.

I am going to guess that the 36A came with the divide and manual oiler installed at the factory. I can see the divider plate between the fuel tank and the cover on the saw pictured above.

McCulloch 1-40 patopgut1.jpg

Mark
 
I installed a LRB piston in this iron bore SP125, actually seems to run very well. We will have to wait and see for how long...

20240731_171142.jpg

20240731_171149.jpg

It is rough, but all together and operational.

I also used my own fabricated pulse and fuel line kits. Throttle and choke linkages appear to be shop fabricated as well, but they are functional.

20240731_172024.jpg

Mark
 
I installed a LRB piston in this iron bore SP125, actually seems to run very well. We will have to wait and see for how long...

View attachment 1194333

View attachment 1194334

It is rough, but all together and operational.

I also used my own fabricated pulse and fuel line kits. Throttle and choke linkages appear to be shop fabricated as well, but they are functional.

View attachment 1194335

Mark
That's ironic I just installed a LRB piston in a 700. The cylinder was thin at the transfers and 2 holes appeared on the outside of the block so I filled up to the fins with JB should be fine as it's near the intake. I have complied a data sheet of the differences in OEM and LRB and have had to "MACngineer" the piston. I had to think back to the large frame pistons and where they used thrust washers to help center the rod when installing the LRB piston because the area between bearing bosses is bigger by .0565 of an inch. I'm curious if guys don't do the same as I did and it allows horizontal play on the piston, it is my theory at least that if thrust washers weren't used the piston could eventually catch a transfer port.

So far it's held for one tank of gas and that was all cutting out the gate. Unable to post my video as it's to long so here's a brief look at what I have found thus far.

●Nos rings .0240
LRB rings .0460
●Spacing between bearing bosses is .0565 bigger then oem, causing more rod play on the piston
●Wrist pin is .026 smaller then nos
●Exhaust side not marked (may be issue for inexperienced hobbyists)
●casting flaws ( nothing a dremel couldn't fix and patience)
 

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