McCulloch Chain Saws

[heimannm]

I won't be home 'till later this week but I think I recall from the McCulloch carburetor book that all of the HL's had the same size throttle bore and venturi bore.

I believe I covered several in another thread some where but I haven't tried to search it out recently.

Mark

 

[pioneerguy600]

The Tillotson carb. factory manual claims that the HL`s had venturi ranging from 1/2" to 7/8". The HL-19 has a venturi of 11/16' and the HL-227 having a venturi of 7/8".
Pioneerguy600

 

[Jacob J.]

The Tillotson carb. factory manual claims that the HL`s had venturi ranging from 1/2" to 7/8". The HL-19 has a venturi of 11/16' and the HL-227 having a venturi of 7/8".
Pioneerguy600

That's good info Jerry. Yeah the HLs vary widely in size and some of the custom HL 3** series have even bigger venturis. I think the HL-19 would work fine on a 797.

 

[leeha]

I just did a few measurements and the Tilly
HL 19 and 63 are at .810 and the Mac Flatback
for the 795, 797 are at around .810 to .815
The small kart Flatback is at .940 which is what
i run on my MC75 and MC100 kart saws.

So i guess i'm wondering which carb will make
more power in the 797? The HL or Flatback.
I would like to try a HL with a tad bigger bore than
.810 but don't know which number carb will fit.

 

[briantutt]

PM 650 Sprocket

I need to get a new rim/drum from my PM650. Looks like I can get either a 7 or an 8 slot. Which is going to be best if I put a 20" bar on it with normal non-safety chain?

 

[GASoline71]

I just did a few measurements and the Tilly
HL 19 and 63 are at .810 and the Mac Flatback
for the 795, 797 are at around .810 to .815

Thanks Lee... looks like the HL-19 will work just fine in my 797.

Gary

 

[stinkbait]

I need to get a new rim/drum from my PM650. Looks like I can get either a 7 or an 8 slot. Which is going to be best if I put a 20" bar on it with normal non-safety chain?

I would go with the 7 tooth. I think that the 8 tooth sprocket would be too much for the saw with a 20" bar.

 

[leeha]

Thanks Lee... looks like the HL-19 will work just fine in my 797.

Gary

Gary, Look at your tilly 19, If it's like mine
then i believe the 19 was the original carb for
the 895 geardrives. The throttle shaft on the
left has the provision for the air vane govenor.
I think i might try the 63 unless i can find one
a hair larger.


Lee

 

[GASoline71]

You're right Lee... it does.

It's bolted in the 797 right now. Its the way I got the saw from Rich Dougan. I have started and ran the saw... seems to work okay... but... I'm always willing to try somethin' else if it's mo' betta.

Gary

 

[leeha]

I did some lookin on Acres site,
And one of the 895's he has list
has the HL291BC carb and he states
that saw was built 1966-67. I wonder
what size that 291 is.
I'm gonna have to start checking out the old Tilly's


Lee

 

[heimannm]

Well I did get home last night and looked through the McCulloch carburetor book I have. There are three HL's listed, 19, 63, and 103 if I recall correctly. All three are listed as .812" throttle bore and .625 venturi (maybe it was .675?).

These are used on the 200/250's - 80 cc class up through the 797 @ 123cc.

Mark

 

[leeha]

Nice info Mark, No listing for the HL291?
Acres site could be wrong.
Do know the venturi size on the flatbacks.

Lee

 

[heimannm]

The McCulloch book that I have only lists a few that are used in their saws. Keep in mind this book was published in the early '70's.

There must be a dozen or so different Walbro SDC's, a few Tillotson HS's, the HL's, and I think the rest are all McCulloch carburetors exept for the Mini Mac, don't remember what it is right now.

Let me have a look later today or tomorrow and I will try to report back on some of the McCulloch carburetors. I know there is at least one "pressure pulse" carburetor listed that has no venturi, straight through design with the fuel literally being pumped into the throttle bore, no low pressure "pulling" the fuel through a venturi.

Mark

 

[Brmorgan]

The McCulloch book that I have only lists a few that are used in their saws. Keep in mind this book was published in the early '70's.

There must be a dozen or so different Walbro SDC's, a few Tillotson HS's, the HL's, and I think the rest are all McCulloch carburetors exept for the Mini Mac, don't remember what it is right now.

Let me have a look later today or tomorrow and I will try to report back on some of the McCulloch carburetors. I know there is at least one "pressure pulse" carburetor listed that has no venturi, straight through design with the fuel literally being pumped into the throttle bore, no low pressure "pulling" the fuel through a venturi.

Mark

Almost like McCulloch was trying to come up with some kind of fuel-injection system for their saws, eh? They had a lot of neat (and sometimes hare-brained) ideas back in the day.

 

[Jacob J.]

Almost like McCulloch was trying to come up with some kind of fuel-injection system for their saws, eh? They had a lot of neat (and sometimes hare-brained) ideas back in the day.

That was the cool thing about McCulloch, they were constantly experimenting. They made a piston for the 4-30 saws that used two thin rings and one thick ring. They also made many custom cranks for a number of their popular saws.

 

[GASoline71]

Great info Mark! Thanks!

Gary

 

[heimannm]

From: Usage Guide & Illustrated Parts List

McCulloch Engine Carburetors, Copyright 1970

I won't try to list all the models for each as some have pretty extensive lists.

Carburetor venturi throttle bore used

Walbro
SDC2 .625 .759 10 Series
SDC3
SDC4

SDC7 .625 .750 Mac 15 (no fuel pump)
SDC16 .625 .750 10-10, Super 10-10
SDC17 .750 .812 70 cc 10 Series, 2-10A
SDC19 .750 .812 795L, Super 797
SDC20 .750 .812 CP125
SDC22 .750 .812 Super 2-10C

McCulloch
MDC2 .484 .625 PM6, PM6A
MDC3 .484 .625 Mini-Mac 6, 6A

Tillotson
HL63 .687 .812 250, Super 250, 550, 660
HL19G .687 .812 895

HS43 .625 .750 1-10, 10-10A
HS71A .687 .812 LG2, G70
HS70A .687 .812 CP125
HL272A .875 1.00 940 Welder
HL103 .687 .812 Super 797

McCulloch
MAC1 .687 .812 Super 250, Super 550
MAC6 .687 .812 895
68795 .687 .812 MC49C

BDC2 1.375 Mc91, Mc101
BDC4 1.375 Mc91, Mc101
BDC14 1.125 1.375 Mc91, Mc101


The BDC2 & 4 are pressure pulse, no venturi, just a "straight through" design.

Mark

 

[leeha]

Please keep us posted Mark.
Nice info.

Thanks Lee

 

[heimannm]

That is everything in the book I have, just sort of a snap shot of vintage McCulloch saws & carburetors.

Hey guys, I don't have any CP or LG saws in my collection so far, anyone have an idea how I can correct this defficiency?

Mark

Woo Hoo - I posted #1000 in the McCulloch thread!

 

[sawbones]

Hey guys, I don't have any CP or LG saws in my collection so far, anyone have an idea how I can correct this defficiency?

Mark

Woo Hoo - I posted #1000 in the McCulloch thread!

what is a lg?

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