McCulloch Super 797 Horsepower Question

[Alaskan Stihl]

Got a question...

Got into a debate on Power of Chainsaws with a friend of mine going on...

I told him that... I heard...that the McCulloch Super 797 was one of largest saws that was sold to the general public (IE: Engine displacement size). My friends reply, is that I was incorrect and (keep in mind that I told him the largest that "McCulloch" produced...) anyway, he brought up that the new Stihl 881 Magnum is the largest and most powerful chainsaw manufactured for the public. Since I am not an expert, I kept silent and went to do some more research...

Survey says....

It appears that the Stihl 881 Magnum has a displacement of 121.6cc whereas the McCulloch Super 797 is 123cc (uh-oh...looks like McCulloch beats the magnum by a couple CC's!) My friend isn't going to like hearing that tid-bit!! haha!

So....

When I came back and told him about my findings...he replied that he was talking about HP and not Displacement (uh...wait a minute slick....that is not what we originally discussed...but whatever). Anyhow, I replied..."Well, I was talking displacement & engine size...not Horsepower!" geeez louis!! I replied that I kind of figured that a saw manufactured in 1969 is not going to have the technology and engineering of a saw produced in 2022 (heck there are even fuel injected saws out now!!)

However, stranger things have happened!

So, I looked up the HP for the Stihl Magnum and it says it cranks out 8.6bhp (braking horsepower). Now, the big question: "Does anyone have any specs on how much Horsepower the McCulloch Super 797 produced? (I know that McCulloch kept that information hush-hush...but maybe someone has some data somewhere?)

Thanks!

 

[Maintenance Chief]

Check out" Dyno Joe" on you tube , he has run a bunch of saws on a dyno.
Some of the McCulloch 125s with the factory cart motor made well over 10hp , but there's plenty of saws that were over 130cc .

 

[Hinerman]

@heimannm

 

[heimannm]

There were several McCulloch saw built with the 123 cc displacement engines, 797, Super 797, CP125, CP125S, SP125, and SP125C. The Stihl likely has an advantage in chain speed and would would well pulling shorter bar (up to 36-42") but over that I think the torque and broad power band of the reed engine McCulloch would win out.

For what it's worth, the Super 797 was actually somewhat detuned when compared with the "regular" 797. Most (but not all) Supers had an SDC carburetor vs. the Tillotson HL on the regular and were equipped with thick rings vs. thin rings on the regular.

Lee Harvey would be our resident expert and he has stated elsewhere that the 797 was the best of the 123 saws for raw power.

A CP125 with a 48" bar had no trouble in an oak log that used all of the bar.



Mark

 

[Bigmac]

I, just by feel think the 797 standard is in the 7hp range, think the sp125c is the mac hp king for stock, non kart application. The lower rpm torque is decent.
If your talking big cc saws of the day the 090 is 137cc. If I remember correctly the 881 was around 10hp on the dyno.(can’t remember if that was with some mods) I think it’s by far the strongest stock saw. Love my Mac’s and haven’t ran an 881, but am pretty sure it’s the king.
Think it’s going to take a modded kart Mac to come close. A big carb 797 might gain, but I don’t think enough. The stock sp125 carb is small, I have no idea what a stock style kart saw would make for hp.

 

[Red97]

I have not had enough old big bores on the dyno to say for sure.

I would guess the 797 to have a very flat power curve without a bunch if extra hp. Would expect to see 7ftlb and 7hp with a few thousand rpm spread 4-6k or so for the peaks.

Which that isn't far from the other limited rpm stock modern Rpm saws 3120,880,1201. If they can handle spinning 11k+ it is possible to make really good power. The 881 makes the most I've seen from any if the modern stock big saws. But the other pass it once ported.