Mac 250 difference?

[mogulmasher]

Hey I've got an old Mac 250 and also a 1-52. Saws are almost identical but the 1-52 seems to cut a lot better than the newer 250. Both are 80cc with 20" bars and .404" chain.

I'm guessing the 250 and later the Super 250 we're the most updated version of the 1-40 thru 1-53 saws? Was there any difference in any of the 80cc motors used in these saws?

I just love how these old saws cut, no high rpms they just chug their way through the wood with no bog at all.

 

[RandyMac]

The Super is 87cc, will rev 9k in the cut with a 36'' bar, it was the last of the line.
There variables between new saws can be noticable, older used ones even more so.
The 250 is a mid range saw, set up for durability, with more power than some of the other 80cc versions.

 

[mogulmasher]

I knew the Super was 87cc. Is there any difference between all the 80cc versions? Porting, carbs, etc?

 

[RandyMac]

McCulloch made constant developments in the 80cc models, many different configurations.
Most 80cc saws were low stress, high durability, meant to last a lifetime.
As time went on, with changes in design and materials, power and rev range went up, without effecting longevity.
The 250 is the epitome of this type of 80cc McCulloch. the 1/2 ton, inline six, three on the tree pick-up of chainsaws.

 

[SEAM]

The SUPER 250 and the 300-550 line also did have an auto oiler...

 

[mogulmasher]

Ok, so my 250 should run a little better than the 1-52 then. It just doesn't seem to run as good in the wood as the 1-52. Of course they have some years on them so condition could vary. Cosmetically the 250 is way nicer, the 1-52 looks like it was run hard and put away wet, then fell outta the truck on the way back to camp.....

 

[Chainsaw Jim]

They tend to run real good after replacing the crank seals and carb kit. Tune the high jet in wood for the most power.

 

[mogulmasher]

Cool maybe a good going through is in order then.

 

[RandyMac]

Some, not many, 250s had auto oil, I have one out of my five 250s. Every one of them has something different about it, no guessing why.
Super 250 on the left, 250 on the right.

 

[Chainsaw Jim]

Another thing to check is the reed valve petals. Warpage or wear will cause running and tuning problems.

 

[RandyMac]

 

[mogulmasher]

That's a great looking saw. Is that a 34" bar? Also did you switch to 3/8" chain?

 

[mogulmasher]

Here's my 250.

 

[mogulmasher]

And here's the 1-52. It's got a yellow 1-40 AF cover on it, but is stamped 1-52 on the bottom.

 

[RandyMac]

36'' bar and yes, 3/8th'' chain.
That is an early 250, it was NOS, but both sides were stripped of most parts and covers.
I put together with new or very nice parts and some extras like the rear handle grip and the wraps, also replaced the Flatback with a Tilly.

 

[mogulmasher]

Nice it's a sweet looking saw. How's it pull the 36" bar?

 

[RandyMac]

Nicely, I filed it to match the saw's power and rev range.

 

[mogulmasher]

Sweet, thinking I need to put a 28" on mine with 3/8" chain for some of those big oak logs.

 

[wcorey]

A few years back I took some timing numbers from the three I have.
And actually wrote it down, lol.



S250 ex duration is 168 with 27 degrees of blowdown, while the other two are close to each other at around 154/20 and 156/19.
Would be interesting to raise the transfers on the Super and raise the exhausts on the other two.
Don’t think I really want to find out the hard way if it does or doesn’t fly though.
Wondering if the difference in blowdown may have something to do with mufflers, the super has a can while the others have stacks.

 

[RandyMac]

This is my beater 250, cut a lot of timbers, ties and glulams with it.