Legal Disclaimer - what I am about to post is based on my experiences and research. I am a relative newb on the whole matter as I have only been messing with these for a couple of years. This comes with no promises except that I have done my best to describe things as well as I can. I welcome anyone to add their comments, suggestions, recommendations, etc.
Many are reluctant to work on the old McCulloch carburetors because they are not Tillotson HL's or other more familiar models. In addition, most of the old Mac's have a primer in place of a choke, which adds to their mystery and in many cases their tendency to be leaky. On top of that, the diaphragms that we can get today are pretty expensive, normally $30 for the set of metering and fuel pump diaphragms with their gaskets.
I have several saws with the old McCulloch carburetors and have been struggling with a few of them myself so lately I decided to just try and document step by step what I've been doing in hopes of helping others, as well as prompting some of you to jump in with better ideas and solutions where applicable.
I will be showing several different saws and carburetors as we go through this, but will try to make it flow in a reasonable logical manner to make it as easy to follow as possible.
Let's get started:
Here is my 795, this carburetor looks pretty bad, but the saw did run, just not very well.
On this saw I had to make a clip to hold the throttle push rod. I don't think the push rod was stock, or maybe the carburetor had been switched already. There should have been a little clip on the carburetor for the rod to slide through but the rod is so bent up it would never have worked anyway.
This is what the clip is supposed to look like.
On this saw, there is no solid connection between the throttle push rod and the levers on the throttle shaft. When the push rod come forward it pushes the lever forward, and when the throttle is released it shuttles and pulls the other lever back.
See the spring on the throttle shaft? Keep going to the next post.