McCulloch Chain Saws

[Jethro 2t sniffer]

Picked this one up not long ago let me know if you want anymore pictures of the 4300. I was also the guy that ended up with the Pro Mac 800 on ebay with the busted up oiler
I do have all the parts to fix that one if things go good. Kevin

Another Kevin cool we got three here now keep us posted on the 800 everyone was watching that and it's nice to see what will happen to it

 

[Jethro 2t sniffer]

I love my Homies but to be honest the XL-12s I have couldn't touch a 10-10s in any cutting situation, even with brand new bar and chains , the 10-10s was just in a different league, the only advantage modern saws have are antivibe , I wouldnt even say weight because to buy the kind of power that saw has in modern terms you'd have to buy a bigger saw.
Guys who say rpms are higher can't put a 24" bar with an 8 pin sprocket and cut with it,but the 10-10s will happily.
I'm sure your friend will treat you right.

This exactly is my love of these saws rpms are all well in good but it's got to hold it there in decent sized wood not just 16 inch cookies who's cutting faster when the peaky plastic saw keeps bogging and dying out while the mac can pull the numbers it makes

 

[Jethro 2t sniffer]

I love my Homies but to be honest the XL-12s I have couldn't touch a 10-10s in any cutting situation, even with brand new bar and chains , the 10-10s was just in a different league, the only advantage modern saws have are antivibe , I wouldnt even say weight because to buy the kind of power that saw has in modern terms you'd have to buy a bigger saw.
Guys who say rpms are higher can't put a 24" bar with an 8 pin sprocket and cut with it,but the 10-10s will happily.
I'm sure your friend will treat you right.

This exactly is my love of these saws rpms are all well in good but it's got to hold it there in decent sized wood not just 16 inch cookies who's cutting faster when the peaky plastic saw keeps bogging and dying out while the mac can pull the numbers it makes

 

[fossil]

Picked this one up not long ago let me know if you want anymore pictures of the 4300. I was also the guy that ended up with the Pro Mac 800 on ebay with the busted up oiler
I do have all the parts to fix that one if things go good. Kevin

Thanks for posting that pic Kevin. It looks to be similar to the late PM700's

Nice find!

 

[Gaspowered]

Ok sounds like you have covered it all. You could crank the jets in and block them off and the use a bottle and keep it running with and see how you go perhaps your just flooding it.

That's a good idea. I made a little fuel bottle for squirting gas in cylinders to check for spark. I try not to over-choke it and I constantly blew off the plug and cranked it over to clear the cylinder. I also have a question about the fuel pump, I noticed that is has two diaphragms. It has the tan colored one with the hole punched out and then the one that is black and is solid. I am not sure if I installed them correctly, but I looked up a diagram and it went pump cover > gasket > tan > black. Last thing i'll do is check the larger welch plug.

 

[rwoods]

I dont know if " projects" are likely to satisfy the accounting department, but a running saw of that caliber is practically ridiculous and probably for only a serious collector.
I would think you'd take a pretty significant hit on anything not running, but I could be wrong.
Parting stuff out is time consuming and requires dedication, if your time is cheap that might be the way to go.

No plans to part out. I was referring to all of the parts I have accumulated. My original plan was to build a sleeper kart saw, but after I got the PNW saw and discovered all the names engraved on it I thought I should keep it as is. Fortunately while checking the compression I discovered the binding connecting rod - so I never started it. Years later, Brian and I did a little swapping and he rebuild it. With new bearings the binding disappeared. I digress and am getting ahead of the story . Since I decided to keep the PNW "stock", I purchased a 101B motor, sloper intake, numerous 101 parts, and enough 125 parts to build the sleeper saw. Building a sleeper with a large kart carb is easier said than done, especially when you want to retain a working choke and manual oiler. Realizing that even if I built the hottest kart saw ever I still lacked the skills to exploit it and I live in an area where there probably aren't two other people within a hundred miles that would appreciate it.

I could easily put the other motor on the PNW saw but I would lose some of its authenticity. Or I could put together a DYI kit 101B saw and consider other options for the PNW such as re-sleeving or chasing after a big piston. Or sell things the same way I gathered them.

Ron - check with Terry Ives in Granite Bay, California on a 0.100" oversize piston, if they are available he will have one.

Mark

When I last spoke with him he had none. He had a .060 block, piston, oversized wrist pin and rings at the time for a fair price. The best set up I am told is the 125 rod with the bearing in the end but you need a standard bore block or find an even more elusive oversized piston.

Ron

 

[Goinwheelin]

Hey there, I am new to this forum and was told to go to this thread after asking for help with an early model 10-10 Automatic. I am working on it for a friend, he brought it to me saying it hadn't been run in about 35 years. Typical issues from sitting, dirty points, varnished carb, etc. The fuel tank was dry and clean also. I cleaned and gapped the points at .020", nice blue spark. I cleaned and rebuilt the carb, installed a new fuel line and filter, new plug, and it started, but died immediately. I had both screws out at 1 1/2 turns. I tried richening them both by about 1/2 a turn each and same problem. Starts then dies. I tried to choke it while it runs but within about 4 seconds it quits. This morning I took the carb off and removed the high speed welch plug and checked the screen, and it was clean. I replaced the plug, put it all back together and it's still not wanting to run, and at this point it seems like it's getting flooded. I did use the Walbro tool (This saw has the Walbro/McCulloch SDC carb) and set the metering lever height accordingly. I am NOT going to give up on this saw, and besides, it's not mine. I also noticed that a small stream of gas comes out of the gas cap, but I think the vent is just bad. Also, I cleaned out the muffler too but honestly it wasn't that clogged. At this point i'm stumped. (No pun intended) Any suggestions? What I might do is remove the other welch plug and soak the carb in my ultrasonic cleaner. Thanks.

had the same problem with my 850. Turned out it was the duckbill in the fuel cap. Tank can’t vent, builds pressure and floods the carb.

Edit: I think I have it backwards. It’s not pressure it’s vacuum in the tank, the fuel pump can’t pull fuel.
if you open the tank and there is a rush of air that’s it.

 

[Gaspowered]

had the same problem with my 850. Turned out it was the duckbill in the fuel cap. Tank can’t vent, builds pressure and floods the carb.

Edit: I think I have it backwards. It’s not pressure it’s vacuum in the tank, the fuel pump can’t pull fuel.
if you open the tank and there is a rush of air that’s it.

That actually sounds like it could be it. I hear about those things all the time. Homelites, McCullochs, Stihls, you name it. I know that over time those things leak, but this thing was actually acting like it had pressure because it was "squirting" out of the vent hole. I heard that Homelite XL caps will work, I will try tomorrow. This may help a lot. I also like that old McCulloch thermometer on your profile pic.

 

[kbeck]

Thanks for posting that pic Kevin. It looks to be similar to the late PM700's

Nice find!

Pretty much the same, name plate probably different and the decals pretty clean saw won't see much use
I have a beat up 700 for that

 

[Maintenance supervisor]

No plans to part out. I was referring to all of the parts I have accumulated. My original plan was to build a sleeper kart saw, but after I got the PNW saw and discovered all the names engraved on it I thought I should keep it as is. Fortunately while checking the compression I discovered the binding connecting rod - so I never started it. Years later, Brian and I did a little swapping and he rebuild it. With new bearings the binding disappeared. I digress and am getting ahead of the story . Since I decided to keep the PNW "stock", I purchased a 101B motor, sloper intake, numerous 101 parts, and enough 125 parts to build the sleeper saw. Building a sleeper with a large kart carb is easier said than done, especially when you want to retain a working choke and manual oiler. Realizing that even if I built the hottest kart saw ever I still lacked the skills to exploit it and I live in an area where there probably aren't two other people within a hundred miles that would appreciate it.

I could easily put the other motor on the PNW saw but I would lose some of its authenticity. Or I could put together a DYI kit 101B saw and consider other options for the PNW such as re-sleeving or chasing after a big piston. Or sell things the same way I gathered them.



When I last spoke with him he had none. He had a .060 block, piston, oversized wrist pin and rings at the time for a fair price. The best set up I am told is the 125 rod with the bearing in the end but you need a standard bore block or find an even more elusive oversized piston.

Ron

If your PNW saw runs I'd keep it original and sell the other if not going to compete with them.

 

[Jethro 2t sniffer]

Pretty much the same, name plate probably different and the decals pretty clean saw won't see much use
I have a beat up 700 for that

Tell Mark you require a 125 and you can trade him the 4300 lol. Not many Mac's Mark hasn't got.

Sorry Mark

 

[PogoInTheWoods]

I cleaned and rebuilt the carb,

You mentioned pulling the one welch plug but didn't mention whether or not you replaced the diaphragms. And I would definitely give the carb a USC bath just for good measure considering its age -- especially if it were varnished up.

And it may have good enough pulse to flood, but an air leak somewhere else keeping it from running without the choke.

 

[Gaspowered]

You mentioned pulling the one welch plug but didn't mention whether or not you replaced the diaphragms. And I would definitely give the carb a USC bath just for good measure considering its age -- especially if it were varnished up.

And it may have good enough pulse to flood, but an air leak somewhere else keeping it from running without the choke.

I did replace both diaphragms, metering and fuel pump. I only pulled the plug that had the little screen where the "main jet" is. To be honest, the carb wasn't that bad when I opened it up but those holes and passages are tiny so pretty much anything can clog them. Last thing I could try is replacing the insulator block gaskets, but I have had good luck with the USC before, so I'll give it a try.

 

[Maintenance supervisor]

I did replace both diaphragms, metering and fuel pump. I only pulled the plug that had the little screen where the "main jet" is. To be honest, the carb wasn't that bad when I opened it up but those holes and passages are tiny so pretty much anything can clog them. Last thing I could try is replacing the insulator block gaskets, but I have had good luck with the USC before, so I'll give it a try.

Check valve, get one.

 

[Goinwheelin]

Made some progress on the 1-70 this morning. New crank seals, MOTO seal on the stuffer plate, and cut a gasket for the oil tank. Left the rings and bearings alone as they checked out. I have a ton of pics, and made notes so I might put a thread together on it.

 

[huskadolmar]

So....i dont know if its q port quirks, a bad port job in its life or what but my pm800 is just not getting there. It starts hard on zama carb. Runs in the cut with good power, but has a floating low. It dont idle or snap right. With walbro 37 it runs like gold but runs out of fuel buried in 26" walnut. I have to keep it 3/4 throttle. I tried a few zama carbs and cant make it idle right or snap right. If it idles hot, it has to be full throttle and drops a little before catching. Light throttle will stall it and its 4 pulls till it fires up. Wont fire choked till about 6. I cant seem to sort it out. New crank seals,intake,impulse,all gaskets,resealed clamshell, excellent compression,though it takes a quick pull im over 180 psi....even slow im at 165. If i pull like a bandit it shows 195 at third pull. Q port makes compression test flaky. Any thoughts

 

[Gaspowered]

Check valve, get one.

This model carb doesn't use any check valves. Only ones I see are on the fuel pump diaphragms. But it sure is acting like there is one in there somewhere.

 

[heimannm]

I have the Zama on several 82cc saws and they are all very good performance wise. If the carburetor has a lot of hours on it the throttle shaft can get a little sloppy and allow inconsistent air leaks but I think that is unlikely with your compression unless someone has been in there to replace the piston and/or rings. From the Zama literature, there should be a check valve in the main nozzle. Frequently these are not easy to service.



Mark

 

[fossil]

My late PM 700, grey oil tank and black covers, Has a 1/4" fuel line pass through in the fuel tank. 1/4" OD Tygon fits perfectly.

Anyone know if the OEM line was rubber or?

 

[Maintenance supervisor]

This model carb doesn't use any check valves. Only ones I see are on the fuel pump diaphragms. But it sure is acting like there is one in there somewhere.

Ok the welch plug with the screen in it, there is a brass insert that holds the screen with a ring holding the screen , UNDER THE SCREEN there should be a flat peice of diaphragm material or a tan piece, usually its bunched up or turned to goo .... if you remove the plug and open the throttle while shinning a light through the bore you should NOT see light under that screen aka the check valve should be blocking it, now if its the tan material it may be opaque enough to see some dim light.
I have not had any luck removing the screen and stuffing the tiny material in place so a check valve kit is always on hand 86-523 walbro kit number.
Tillotson carbs do not have a screen hence no check valve/ screen = check valve.