McCulloch Chain Saws

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The pm4300 is also the same as the pm700 or pm700s

The 7-10 was a points style ignition and the 700 and later had electronic ignition. There were other differences but for the most part, they are the same
 
A parts list I looked at showed that the 650 also uses a different clutch drum that takes a rim sprocket. It also looks like a decompression valve was offered on the 650, but this was just a 1987 IPL I looked at, so I guess these differences are only for that year. There could have been decomp valves offered on the 610 other years, for all I know. I know the 610 was known to be heavy for the power it offered, and with the greater power, I guess the 650 compared more favorably to other saws in this category back then.

Scott in Penfield NY

EDIT: oops, looks like I replied to a day-old post, which makes my reply look "out of place." This was in reference to a post about differences between a 610 and 650.
 
Last edited:
80sDweeb said:
A parts list I looked at showed that the 650 also uses a different clutch drum that takes a rim sprocket. It also looks like a decompression valve was offered on the 650, but this was just a 1987 IPL I looked at, so I guess these differences are only for that year. There could have been decomp valves offered on the 610 other years, for all I know. I know the 610 was known to be heavy for the power it offered, and with the greater power, I guess the 650 compared more favorably to other saws in this category back then.

Scott in Penfield NY
Click to expand...

You're right about the decomp. It was on all pm650's and pm655's. In my opinion it wasn't needed though. I never pushed it in to start any of those that I had. I don't think it was on any 610's or 605's.

As far as the rim sprocket, I've seen it on both 610's and 650's. I guess someone could have put it on the 610's I've had. The rim type drum for the 650 is compatible with the other 600 series saws as well as the 10-series.
 
I got a PM610 a couple weeks ago that I was told "hasn't run in decades", and a few days ago I finally had a chance to clean it up a little, got all the old oil and gook out from around the brake and clutch area, washed out the air filter, etc. The next day I gassed it up and tried to start it, but no joy. Didn't really look any farther, just pulled it through as many times as I could stand (this is a 60cc saw, after all, and I'm quickly aging at 51 years.) Not a pop. I think I'll pour some mix down the carb next and see if I get a pop, and pull the plug and check for spark. Last night late I didn't want to mess around with it out in the cold garage, so instead I brought it inside, took the carb off and pulled it apart. Didn't seem like there was much gas in it for my having tried to start it a day or so before, so I suspect the diaphragms have gotten stiff. I also noticed the little "flappers" in the pump section looked a little curled. No point fighting with it, so I ordered a carb kit on eBay, and I hope that's all it will need. While I wait I'll do those other checks, and I still put the carb back together, and I'll try to get it to fire as-is, but I could see a kit will make a big difference.

It came with a 16 inch bar, and I've already bought a 20" Oregon D70 chain, looking for a used bar with some life left in it now. Guess I need to visit the Tradin' Post (as soon as I recover from Christmas, that is!)
 
I don't know if it makes a difference but the super model included a zama carb. I know from other 2 stroke stuff zama carbs are a performance carb. Only drawback the few zama's I have rebuilt are alot more time consuming with more parts.
 
Yeah, baby! I picked up a compression tester at Harbor Freight and checked the PM610, only read about 135 or so. I was worried (I guess I still am) but I went ahead and tested the spark and it was good, so I pulled if through a bunch of times with ignition off, then turned it on and gave it a few tries and it started to pop. A few pulls later and it was running, after more than 20 years. Nice! It seems to need a little more gas on the low end, but I don't know if I should even try to tune this carb with the old membranes in there all stiff like that. So now that it starts, I'm not sure if I've really got low compression, or just a bad tester. I'll have to see if I can figure out a way to calibrate it.

I was so single-minded about hearing the saw run, I forgot I had loosened the bar nuts, and once it was running the bar started wagging around, oops. I've got to remember these things aren't toys...

Seems like an awful lot of saw for a 16" bar, tho.

Scott in Penfield NY
 
The 610 I've had in wood wears a 16". Felt pretty good. My other 610 has a 20" on it. 16"-20" is about right for a 60cc saw in my opinion.

If the compression on your saw really is down at 135 psi, then it's getting about time for some new rings.
 
Wow, a lot of water has passed under the bridge while I have been travelling.

Good news is I am home for a few days and will try to do some catching up.

Just a couple of notes, lots of parts out there for RH & LH start 10 Series saws, the RH start version does require the clutch with the starter pawls. There were drums with spur sprockets, drums for rim (spline) sprockets, and Auto Mac/Easy Mac sprockets with a rim type sprocket welded to the drum. Spur sprockets were 7T 3/8" pitch and a few in .354, a McCulloch red head step child. Rim (spline) drums came with the standard small spline and large spline. Auto/Easy Mac sprockets were 3/8" as well as .354 pitch. Lots of choices so choose carefully. Lots of early 10 Series saws had hard nose bars so you could change the pitch without worrying about matching the sprocket in the nose of the bar.

The 10 Series and 600 Series clutches are identical and interchangeable, except for the RH starter pawls noted above. Some have a key and use a regular RH thread but, the ones without key are intended for saws with LH threads. As with all things Mac, there were a limited number of SP80 saws that had a peculiar 3 shoe clutch and as best I can determine, the 3 shoe clutch had a different taper. I have yet to find an SP80 with the "original" crank shaft that will accept he 3 shoe clutch.

If I could remember or find the specific references...I believe the 605 and 610 were smaller displacement (3.4 In³) and the 650/655 and others were 3.7 In³. Wish I could remember exactly where were which. Some were good enough to include it in the model label as in Timber Bear 3.7.

I have some 3-25 carburetor parts, diaphragms etc. so contact me if you have a need, I will try to be reasonable for 60+year old parts that are no longer available anywhere...

Now I hope this has not been a waste of your time.

Merry Christmas everyone!

Mark
 
The 3.4Ci or 55cc are as follows...pm605, eager beaver 3.4, timberbear, silver eagle 3420

The 3.7Ci or 60cc are pm610, pm650, pm655, pm610 super, eager beaver 3.7, pm5700-20

This list doesn't include the ward models like the TMY24084A which is the 3.7Ci
 
Other notes, the earlier saws had brake handles that pivot on the left side of the saw. The later models had the flag style brake handle. The flag style saws had thin piston rings and the the earlier pivoting brake style had thick rings.


These saws could hold two spikes which was pretty cool.

They had the bar tensioner on the saw which was in my opinion a better design than the 10-series.

Some of the smaller 55cc saws came with a zama carb which had a smaller venturi

Pictures coming soon
 
Flag style brake

4utyhyta.jpg


Pivoting brake

nehe9epy.jpg


Dual spikes

zejaraqa.jpg
 
I did find one with a zama carb. The venturi could be the same, I haven't looked up the exact measurement. The walbro does have a bigger bore though.

usava3u2.jpg


I think this is why I've always seen the zama on the smaller saws.
 
Bruce Hopf said:
I know heimannm has a lot of McCulloch Chain Saws, as well as myself, I was wondering if anybody else has a few McCullochs in their collection of Chain Saws, and are they for work, or for display. Thanks for your input. Bruce.
Click to expand...

Work. They are simple and rugged. They are the AK-47 of chainsaws, especially if you get a 10 series. Parts might be less common but they don't break often as long as you treat them with a bit of respect. Got a dumb ole 10-10 from the late 80's, a PM 610 up at my pops, a PM 700 for general cutt'n, a PM 850 for firewood, and a crappy Eager Beaver 2.3 frank'n saw spliced with a Power mac 330 rear handle to improve the feel of it. I have a 10-10S on the way too because they are the one of the swam song saws for Mac. These machines were made for people who can figure things out on their own more often than not, and do not always subscribe to planned obsolescence. The 10 series were not throwaways and could by all rights run forever. Not a good paradigm if your goal is to sell a lot of chainsaws if you can get away with buying just one that ends up an heirloom.

Yah I am about a bunch of years late on this tread.....
 
I'm guessing the only difference in the 610/650 pistons is the ring thickness? I think my second 610 is a little lower on compression, don't remember putting a gauge on it so I'm not for sure.
 
The 610 and 650 had thick rings in the early years and both were built with thin rings in the later years.

BTW, the 600 series started in 1978 and lasted until they went out if business
 

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