McCulloch Mac 2-10 (Bullfrog carb swap)

[Garflop]

I now own my uncles mint mac 2-10, this saw is lightly used and I want to bring her back up to shape.
I'm a 21 year old landscaper so chainsaws are nothing new but I have never worked on a saw of this vintage, hopefully I don't have touch the points
Anyways my uncles saw has the bullfrog carb and I can get it to run by spraying gas into the carb. But cant get to fire with bullfrog carb, I think its clogged somewhere. It was stored without fuel inside. I have been looking for bullfrog carb rebuild/gasket kit with no luck.
I found I deal for a rough but running 2-10 with the cube carb.
Between the 2 saws do I have the parts I needed to swap. Are there any mods needed to make or is it mostly bolt on.

 

[GoBigRed]

That’s a tillotson carb. Standard on the 1-10 saws and seemed to be on some 2-10s also with the others having a walbro. The carb shoud I have the number stamped on the intake flange. Get that number and call up discount marine parts at 906-466-2180. They will get the correct kit for you. It’s more expensive than kits you will find on Amazon or eBay but it’s also more complete. It will include all your intake gaskets as well as carb gaskets. There are videos on rebuilding the carb and cleaning it and even more on doing work on the 10 series macs.
I did a 2-10 rebuild last year and love that little saw. Honed the cylinder, very mild port work, replaced piston, and rebuilt its walbro carb. That little thing pulls very nice for a 50+ year old saw.
Yes, they are heavy and slower compared to today’s saws, but the 10 series macs are always my go to saw for anything. They are just cool as heck. And when you get it running there will be nothing more satisfying than getting behind the same saw your grandpa ran back when he was making wood chips.
There are a lot of folks on this site with knowledge on macs. Use the resources, take it slow, and you will be very successful with your work

 

[Rocker59]

Firstly, I would like to welcome you to the CAD club, you are on the verge of Yellow Fever. You will soon find a "Parts Saw" will become a "it only need 'this' to become a runner" saw.



The first thing you need is an Integrated Parts List (IPL). A good source for me is:



https://www.mymowerparts.com/pdf/McCulloch-Parts-Service-Repair-Manuals/Gas_Powered_Chain_Saws/


The second thing you need is the 10 series Shop Manual:



https://www.arboristsite.com/threads/mcculloch-manuals.150172/


Addressing the carb swap, the fuel tank assemblies are different (slightly) for the McCulloch "Bullfrog" and the cube (Walbro / Tillotson) carbs. The bullfrog assemblies are held to the cylinder with the carb bolts and a primer button. The cube assemblies have one set of bolts to hold the tank down and additional set of holes and bolts to hold the carb on (to the tank) and a choke button. You'll also notice that the tank heights are different. There is no spacer under the Bullfrog but there is one under the SDC. Later Bullfrog 2-10s had the1 higher tank and a spacer under the carb.



Regarding your uncles 2-10, the carb is a single needle Bullfrog. They have a better primer design in my opinion. There were five versions of the Bullfrog carbs, three single needle, two double needle. There are a few ebay sellers out there who have NOS diaphragm/fuel pump/gasket kits that are in good shape. Take a good look at the pictures, some are used. Also pay attention to the details of the gasket to make sure they match yours (again, five versions. Sellers don't know what they’re selling). There is a duck bill valve post by heimannm (Mark Heimann) that explains how to upgrade to a Homlite style buck bill valve. The primer is easier to work on than the double needle. Refer to the shop manual, it explains the differences between the three types of single needle bullfrogs and also explains the tuning procedure. I have a few saws with the bullfrogs (2-10, 3-10, two 5-10s) and have no issues with performance.



For the other 2-10, it has what appears to be a Walbro SDC-2 (the only one with the external adjustment linkage), so it is either a later 2-10 or one that has had an "upgrade". There were also Tillotson upgrades but the choke poked out when open, not in. Carb kits are readily available. Just remember to hook the diaphragm pin into the meter lever. It does not go on top like other carbs.



I would recommend getting both running and compare the two. Happy sawing.