McCulloch Chain Saws

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A fellow stopped in yesterday with a Jenn Feng 50cc McCulloch that needed starter work.

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With the starter fixed I asked him to start the saw...low and behold it was running backwards? Apparently it fired on the up stroke (as it should) but kicked it backwards and it kept going albeit somewhat lethargic. He switched it off, I suggested he try it again and it was running in the proper direction.

Never say never...

Mark
That's funny because the old ezgo golf carts belt drive ones used to reverse the starter to go in reverse. Then engine was running in reverse. They changed that after a while because you could go as fast in reverse as in forward.
 
Info on pros and cons of Mac thin rings like on 1-72 type saws and similar would be greatly appreciated. I'm debating on whether the saw is worth repairing or not after the new prognosis of the p&c ☹️ what I thought looked good may not of been. I'm at 90# compression and not enough for it to pop off.
 
Generally speaking, the thin ring models were hot rods compared to their thick ring counterparts. I have a 1-72 that I have run a bit, I thought is pulled as well as the 066 Stihl that I had rebuilt with a new piston.

I picked up a bunch of saws from Woody Strommen last year (maybe two years ago already???) and was test running this PM610 on Monday when it stopped very suddenly.

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I'm guessing the wrist pin and/or connecting rod had been reused too many times and the wrist pin slid over releasing the needles.

It was a shame to loose a brand new thin ring piston, those are getting harder to come by these days.

I found a short block laying around in the attic with 155 PSI compression and used that to make the saw operational once again. Currently residing in my "For Sale" rack.

Mark
 

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Generally speaking, the thin ring models were hot rods compared to their thick ring counterparts. I have a 1-72 that I have run a bit, I thought is pulled as well as the 066 Stihl that I had rebuilt with a new piston.

I picked up a bunch of saws from Woody Strommen last year (maybe two years ago already???) and was test running this PM610 on Monday when it stopped very suddenly.

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I'm guessing the wrist pin and/or connecting rod had been reused too many times and the wrist pin slid over releasing the needles.

It was a shame to loose a brand new thin ring piston, those are getting harder to come by these days.

I found a short block laying around in the attic with 155 PSI compression and used that to make the saw operational once again. Currently residing in my "For Sale" rack.

Mark
Yea I was told that my 1-72 thin ring saw with low compression needed to be rebored and a larger piston was needed. Such a cool looking saw.
 
Back in the Mac game. Took me a while to find a bigger Mac I could afford. But got this guy off evil bay. Doesn't run, I didn't have time last night to mess with it much. Compression feels good. Gas just floods out of the carb. Didn't check spark either. Overall it's in decent condition.
 

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Hey guys, need some advice on where to souce parts for the carb on the 1-76. It's got the flat back on it. I've been over the carb thread and have seen mention of getting rid of the capillary screen and installing a check valve, I'm unable to seem to find a kit with the parts listed or parts seperatly. I see sugar creek has a basic rebuild kit for it. the primer leaks too, so there's another mess to deal with. So all this has lead me to thinking about swapping a tillotson hl in, however I haven't been able to find any mention of what model I should be looking for, for a 1-76. I've seen hl 19,63 and 103 (?) Meantioned for smaller displacement saws, and someone mentioned getting a carb off a bigger homelite. They however failed to mention any model number of the saw or carb. Somewhere I have a box full of old carbs so I very may well have another Mac flat back or a tilly that would work but it would sure be a bit easier if I knew a model number of carb to look for, weather I have one or need to get one.
 
Hey guys, need some advice on where to souce parts for the carb on the 1-76. It's got the flat back on it. I've been over the carb thread and have seen mention of getting rid of the capillary screen and installing a check valve, I'm unable to seem to find a kit with the parts listed or parts seperatly. I see sugar creek has a basic rebuild kit for it. the primer leaks too, so there's another mess to deal with. So all this has lead me to thinking about swapping a tillotson hl in, however I haven't been able to find any mention of what model I should be looking for, for a 1-76. I've seen hl 19,63 and 103 (?) Meantioned for smaller displacement saws, and someone mentioned getting a carb off a bigger homelite. They however failed to mention any model number of the saw or carb. Somewhere I have a box full of old carbs so I very may well have another Mac flat back or a tilly that would work but it would sure be a bit easier if I knew a model number of carb to look for, weather I have one or need to get one.
Does saw have spark Sean ?
 
Well I was just going to take a few pics and maybe pop covers off for a quick peek. Famous last words......
Very strange carb settings. I checked prior to disassembly and it was L 1-1/2, H 4!!!!!
After carb cleaning and new parts , I had to go right back to that to get a consistent run?????
View attachment VID_20240419_003456565.mp4
 
Hey guys, need some advice on where to souce parts for the carb on the 1-76. It's got the flat back on it. I've been over the carb thread and have seen mention of getting rid of the capillary screen and installing a check valve, I'm unable to seem to find a kit with the parts listed or parts seperatly. I see sugar creek has a basic rebuild kit for it. the primer leaks too, so there's another mess to deal with. So all this has lead me to thinking about swapping a tillotson hl in, however I haven't been able to find any mention of what model I should be looking for, for a 1-76. I've seen hl 19,63 and 103 (?) Meantioned for smaller displacement saws, and someone mentioned getting a carb off a bigger homelite. They however failed to mention any model number of the saw or carb. Somewhere I have a box full of old carbs so I very may well have another Mac flat back or a tilly that would work but it would sure be a bit easier if I knew a model number of carb to look for, weather I have one or need to get one.
I know that 'oldsawshop dot com' is run by a forum member here and stocks flatback kits.
 
Hey guys, need some advice on where to souce parts for the carb on the 1-76. It's got the flat back on it. I've been over the carb thread and have seen mention of getting rid of the capillary screen and installing a check valve, I'm unable to seem to find a kit with the parts listed or parts seperatly. I see sugar creek has a basic rebuild kit for it. the primer leaks too, so there's another mess to deal with. So all this has lead me to thinking about swapping a tillotson hl in, however I haven't been able to find any mention of what model I should be looking for, for a 1-76. I've seen hl 19,63 and 103 (?) Meantioned for smaller displacement saws, and someone mentioned getting a carb off a bigger homelite. They however failed to mention any model number of the saw or carb. Somewhere I have a box full of old carbs so I very may well have another Mac flat back or a tilly that would work but it would sure be a bit easier if I knew a model number of carb to look for, weather I have one or need to get one.

Hi Sean,

My kits include the diaphram, Diaphragm fuel pump, and two carb gaskets. Unfortunately nothing for primers yet, but I'm sure you'll get some info on a rebuild (and possibly parts for it) from other folks here... My kits are ready to ship, not built on demand.
https://www.oldsawshop.com/McCulloch-Flatback-Carburetor-kit-p561950577
 
Hey guys, need some advice on where to souce parts for the carb on the 1-76. It's got the flat back on it. I've been over the carb thread and have seen mention of getting rid of the capillary screen and installing a check valve, I'm unable to seem to find a kit with the parts listed or parts seperatly. I see sugar creek has a basic rebuild kit for it. the primer leaks too, so there's another mess to deal with. So all this has lead me to thinking about swapping a tillotson hl in, however I haven't been able to find any mention of what model I should be looking for, for a 1-76. I've seen hl 19,63 and 103 (?) Meantioned for smaller displacement saws, and someone mentioned getting a carb off a bigger homelite. They however failed to mention any model number of the saw or carb. Somewhere I have a box full of old carbs so I very may well have another Mac flat back or a tilly that would work but it would sure be a bit easier if I knew a model number of carb to look for, weather I have one or need to get one.
Parker Jameson made a decent video on rebuilding these there is a part1 and part 2. Guessing you could use something like a threaded plug to seal it up if you can't weld like he can.

Part1 :

Part 2:
 
Does saw have spark Sean ?
Didn't remember to check that last night, figure at most it will need points and condenser. Wife gave me proper heck about leaking fuel all over the basement and stinking up the house... she's counting down till I move put to the shop, lol. I'll check it when I get off work and see if it has spark or not.
Hi Sean,

My kits include the diaphram, Diaphragm fuel pump, and two carb gaskets. Unfortunately nothing for primers yet, but I'm sure you'll get some info on a rebuild (and possibly parts for it) from other folks here... My kits are ready to ship, not built on demand.
https://www.oldsawshop.com/McCulloch-Flatback-Carburetor-kit-p561950577
Thanks, got anything else for a 1-76? I'd love a set of the proper decal plates for it.
 
Parker Jameson made a decent video on rebuilding these there is a part1 and part 2. Guessing you could use something like a threaded plug to seal it up if you can't weld like he can.

Part1 :

Part 2:

welding isn't a problem, at most I'll run over to my brother's house and get him to tig the hole closed. Thanks for the videos. I saved them to my play list for future reference.
 
Didn't remember to check that last night, figure at most it will need points and condenser. Wife gave me proper heck about leaking fuel all over the basement and stinking up the house... she's counting down till I move put to the shop, lol. I'll check it when I get off work and see if it has spark or not.

Thanks, got anything else for a 1-76? I'd love a set of the proper decal plates for it.
I also make a fuel tank gasket for the 1-76. Working on making a plate for a 1-71 but it may be a while til thats done....If we get that done and its a win, I may start adding others.

https://www.oldsawshop.com/McCulloch-Fuel-Tank-Gasket-p559107267
 

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