Aaron Rybicki
ArboristSite Operative
[I apologize in advance for writing a novel, but I was trying to be as detailed as possible]
First time posting on this forum, so hello everyone. I have an early 1970s McCulloch Mac 10-10 Automatic chainsaw (according to the Mike Acres site). On his site it claims that the carburetor for my chainsaw model (600002U) and year (1971-1975) is fitted with a "Tillotson HS series (85720)". I find that interesting because the carburetor on mine is a Walbro SDC, which would have been on the previous years for the 10-10A (1967-1970). Not sure if this makes much of a difference, but that's just some additional information. So, here's the story.
Around April of 2014, my grandfather's basement became flooded from a burst pipe due to the cold weather. A couple of buddies of mine and myself sucked all the water up and cleaned that whole place out. Upon cleaning, we found this old McCulloch chainsaw that didn't get touched by the water. It had to have been sitting down there and not ran for god knows how long. I'm going to assume at least since the Early 90s. We took it outside, put some fresh gas in it and it fired up after about 7 or 8 pulls! Later that year in about June I used it to cut some firewood and it ran just fine.
June of 2014 was the last time it ran.
Fast-Forward to 2017 in the beginning of December and it still had the gas from 2014 in it.. The saw had just been put aside for the time being and kind of got forgotten about. I dumped the old gas out and put some fresh 40:1 in it. Pull after pull, it would not go. Compression seemed fine just by pulling and spark was good and blue. So my buddy and I figured it was a fuel issue. We sprayed some starting fluid down in the carb and every time we did that, the first pull, we'd get a good POP. A healthy pop too, like this sucker wants to run! But that's all we'd get and only with starting fluid or by dripping a little fuel in the carb with a straw. No throttle response from it though.
I took the saw to a local small mechanics shop and they determined that the saw need a new crankcase gasket as the old one was basically non-existent and was sucking air from that area. They handed it off to me and pretty much told me they didn't want to work on it unless I'm willing to dish out a lot of money. So my buddy and I tackled it ourselves (pictures included).
We tore it apart and split the saw in two. Due to the rarity of some McCulloch parts, I bought cork rubber gasket material and we made our own gaskets to seal up the crankcase. Both sides lined up perfectly. We slapped it all back together, threw some fresh fuel in and well... we're almost back to square one again..
Fuel is still not being sprayed into the cylinder. One MAJOR difference however, is when we put a couple straw fulls of fuel down in the carb, this thing doesn't just POP for a half-second like before, it runs for about 2-3 seconds off of that fuel AND there is NOW throttle response! Still sounds healthy as ever.
But then it shuts off.
I'm thinking that our homemade gasket job worked and sealed up that leak, but I believe there is either gunk in the carb, seizing the flow of fuel OR the carburetor is in need of a rebuild. We were going to tear into the carb tomorrow and try giving it a thorough cleaning if it is in decent condition and see if that helps.
I appreciate any feedback, suggestions or questions!
Thanks!
Check out my photo album of the saw below if you are interested.
[album=large]1856[/album]
First time posting on this forum, so hello everyone. I have an early 1970s McCulloch Mac 10-10 Automatic chainsaw (according to the Mike Acres site). On his site it claims that the carburetor for my chainsaw model (600002U) and year (1971-1975) is fitted with a "Tillotson HS series (85720)". I find that interesting because the carburetor on mine is a Walbro SDC, which would have been on the previous years for the 10-10A (1967-1970). Not sure if this makes much of a difference, but that's just some additional information. So, here's the story.
Around April of 2014, my grandfather's basement became flooded from a burst pipe due to the cold weather. A couple of buddies of mine and myself sucked all the water up and cleaned that whole place out. Upon cleaning, we found this old McCulloch chainsaw that didn't get touched by the water. It had to have been sitting down there and not ran for god knows how long. I'm going to assume at least since the Early 90s. We took it outside, put some fresh gas in it and it fired up after about 7 or 8 pulls! Later that year in about June I used it to cut some firewood and it ran just fine.
June of 2014 was the last time it ran.
Fast-Forward to 2017 in the beginning of December and it still had the gas from 2014 in it.. The saw had just been put aside for the time being and kind of got forgotten about. I dumped the old gas out and put some fresh 40:1 in it. Pull after pull, it would not go. Compression seemed fine just by pulling and spark was good and blue. So my buddy and I figured it was a fuel issue. We sprayed some starting fluid down in the carb and every time we did that, the first pull, we'd get a good POP. A healthy pop too, like this sucker wants to run! But that's all we'd get and only with starting fluid or by dripping a little fuel in the carb with a straw. No throttle response from it though.
I took the saw to a local small mechanics shop and they determined that the saw need a new crankcase gasket as the old one was basically non-existent and was sucking air from that area. They handed it off to me and pretty much told me they didn't want to work on it unless I'm willing to dish out a lot of money. So my buddy and I tackled it ourselves (pictures included).
We tore it apart and split the saw in two. Due to the rarity of some McCulloch parts, I bought cork rubber gasket material and we made our own gaskets to seal up the crankcase. Both sides lined up perfectly. We slapped it all back together, threw some fresh fuel in and well... we're almost back to square one again..
Fuel is still not being sprayed into the cylinder. One MAJOR difference however, is when we put a couple straw fulls of fuel down in the carb, this thing doesn't just POP for a half-second like before, it runs for about 2-3 seconds off of that fuel AND there is NOW throttle response! Still sounds healthy as ever.
But then it shuts off.
I'm thinking that our homemade gasket job worked and sealed up that leak, but I believe there is either gunk in the carb, seizing the flow of fuel OR the carburetor is in need of a rebuild. We were going to tear into the carb tomorrow and try giving it a thorough cleaning if it is in decent condition and see if that helps.
I appreciate any feedback, suggestions or questions!
Thanks!
Check out my photo album of the saw below if you are interested.
[album=large]1856[/album]
