McCulloch Chain Saws

[cbfarmall]

You are starting to irritate me.:msp_biggrin:

Nice score, Been wanting one myself.


Lee

You've cornered the 797 market, and I only have 3 550s.:bang:

Chris B.

 

[Brian13]

Nice find on the S550 cbfarmall!!! looks like it will clean up nicely.

 

[leeha]

You've cornered the 797 market, and I only have 3 550s.:bang:

Chris B.

Come on now, I did let one 797 go.
Someday i will find a 550. No hurry.


Lee

 

[cbfarmall]

While I'm on the subject of Super 550s, I just finished up this 795-new rings, bearings, seals, gaskets, points, etc... Both the S550 and the 795 have the same bore/stroke. Other than the handlebar/fuel tank arrangements, are there any performance differences between the two. Why would Mac offer 2 different with same displacement at more or less the same time? A look at an IPL list reveals some overlap between the 740/790/795 and the 550/S550.

Chris B.

 

[dieselsmoke]

Maybe a west coast/east coast thing. The 790,795,797's were extremely popular with the fallers out here.

 

[cbfarmall]

Maybe a west coast/east coast thing. The 790,795,797's were extremely popular with the fallers out here.

I'm guessing you're right. The 795 handlebar arrangement goes back quite a long way as far as Macs go.

Chris B.

 

[leeha]

Nice 795 Chris,
But i sure like the bigggg H+S dog.
I belongs on your 797.



Lee

 

[heimannm]

200/300/400/500/600 vs 700/800

I am under the impression that the 700/800 Series saws had different, more aggressive porting than the 200/300/400/500/600 saws. I don't have any evidence to support this other than my experience with each type. I have run my 740 and 795 as well as the 450 and 550, the 700's seem to be much better performance wise. The 440 and 640 were sort of transition saws for their respective model series.

I think the overall design of the 440/640/700/800 was more for long term best performance and the smaller saws were an effort to simply make them more compact. Two very obvious differences are the separation of the fuel tank for the 700/800 saws (keep the fuel tank cooler, less issues with pressure build up) and the external automatic oiler, easier to adjust and service if needed.

These are not very scientific observations, just a bit of experience that I have.

Mark

 

[dieselsmoke]

Mark, have you ever had vapor-loc problems on your front tank models? Say on a hot july day in the mid-west?

 

[heimannm]

If I were ever so foolish as to run one out of gas, or switch it off for a minute or two hot it would be impossible to start it again short of priming directly down the carburetor. When you shut one down when it is warm, the pressure in the fuel tank can be quite impressive, you can hear it boiling in there and the temptation is to open the cap, I generally let them cool down a bit before I did that.

I'm not sure vapor lock is the exact nature of the problem since the fuel tank is actually pressurized so you expect the fuel line to the carburetor would be as well, but certainly the carburetor stops pulling fuel to the point where you have to take other actions like direct priming to get it going again.

When a McCulloch 300 was my only saw (we're talking 30 years ago) I would get in the habit of never letting it stop all day, refueling on the run, etc. to avoid the issues of having to restart a reluctant hot saw.

Mark

 

[dieselsmoke]

I hear ya. I recall my uncle, a Pnw gypo logger, forty years ago cursing the yellow brand for the hot start syndrome, or I should say non-start sundrome. When i was old enough ( 18yrs) to help him he had switched over to homelites???

 

[RandyMac]

Some models tended to flood when hot, not everytime, but often enough. Most likely a hot fuel tank vent problem, I have seen fuel lines piss over the edge from the pressure. While my Super 250 didn't do that, the 660 would in temps over 90. The 797s flooded once in awhile, that devil 895 seemed to know when best to thwart my progress. the PM850 had no vices.

 

[dieselsmoke]

Lil devils disguised in yellow, all of 'em.

 

[rwoods]

Some models tended to flood when hot, not everytime, but often enough. Most likely a hot fuel tank vent problem, I have seen fuel lines piss over the edge from the pressure. ... the PM850 had no vices.

Its little non-AV brother, the PM700, pretty much meets your description of the others (at least mine does). I assume it is the lack of air flow between the tank and the hot stuff. Ron

 

[rwoods]

Compression testing the 125s

I broke down and bought a NAPA small engine compression tester today. It pained me to pay twice as much for it as their longer hose versions. But it sure peaks a lot quicker.

Anyway I checked the 125s today as part of my decision on the next move. Cold - one was 164# and the other was 138#. In comparision I checked two of my PM800s cold - both were 162# and my PM700 cold - 152#.

With the thought of building a good work saw, do I need to consider new rings for either 125?

I may check my other 125 tonight after I catch my breath.

Thanks for your input. Ron

 

[leeha]

I broke down and bought a NAPA small engine compression tester today. It pained me to pay twice as much for it as their longer hose versions. But it sure peaks a lot quicker.

Anyway I checked the 125s today as part of my decision on the next move. Cold - one was 164# and the other was 138#. In comparision I checked two of my PM800s cold - both were 162# and my PM700 cold - 152#.

With the thought of building a good work saw, do I need to consider new rings for either 125?

I may check my other 125 tonight after I catch my breath.

Thanks for your input. Ron

The one with 164 is great, The one with 138 isn't that bad,
Might just need a set of rings or possibly some run time.
What doe's it look like throught the exhaust port?



Lee

 

[RandyMac]

Some Homelites were even worse, the XL925s I ran would boil so hard the cap seemed ready to blow off. I always hesitated to run XL925s on the fireline, the heat sink after boil, when just shut off could mist the area with vapors. The nasty 10-10s were almost as bad, however with that little fuel tank, there was very little fuel left to boil. The 660 would boil moderately, I think it had to do with added heat from the gearbox.

The old vertical cylinder Homelites are the easiest starting of the big inch saws. I have had my ass whipped by McCullochs, but never with a Homelite.

 

[rwoods]

The one with 164 is great, The one with 138 isn't that bad,
Might just need a set of rings or possibly some run time.
What doe's it look like throught the exhaust port?



Lee

Lee, I'll try to get some pictures of the cylinders. I have had so much trouble posting pictures lately I would rather be yanking the starter cord. I have tried all the helpful posts but no success. I may just resort to posting an attachment followed by a post with the attachment opened. Thanks, Ron

 

[leeha]

Ron, I sent you a PM



Lee

 

[rwoods]

Ron, I sent you a PM



Lee

Thanks. Let's see if this will do. View attachment 178230View attachment 178231View attachment 178232View attachment 178233View attachment 178234 Ron