McCulloch 790 build

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Kyle an HL63 also has the AF stud. An HL19 or HL103 will not have the AF stud.

Thanks for that info.


I don't have a 19 or 103 on hand though.


I'll try tweaking the throttle stop and see if I can't get it sorted out.

If I can't get it to work right, then I'm gonna forget about flat backs and stick with Tilly carbs.

It might sit on a shelf with a "Money wasted" label on it, along with the other one that came off of the 1-76 parts saw...or something else.


I'm not happy about the idea that I may have to buy more parts for this thing to run properly. It should do fine with the flat back. If it doesn't... there will be hell to pay and it may be possible that carb will no longer exist... might have to sell the parts out of it and then shoot the carb body with a .45 so no one will never have to deal with it again.
 
I got my latest 640 together tonight but finished too late to give it a rip. Some one before me replaced the McCulloch flat back carburetor with a Tillitson HL 63 and simply cut the stud off leaving the top of the carburetor plugged. I will post some photos tomorrow in the McCulloch sticky.

I know Lee is partial to the Tillotson carburetors but I have several good runners with the flat back and Kyle is right about the primer, when they are working properly they do make starting very easy.

Mark
 
I got my latest 640 together tonight but finished too late to give it a rip. Some one before me replaced the McCulloch flat back carburetor with a Tillitson HL 63 and simply cut the stud off leaving the top of the carburetor plugged. I will post some photos tomorrow in the McCulloch sticky.

I know Lee is partial to the Tillotson carburetors but I have several good runners with the flat back and Kyle is right about the primer, when they are working properly they do make starting very easy.

Mark

That primer is such a good feature that I'm going to do everything I can to get this thing sorted out... not to mention that it would save me money not having to buy another carb.

In any case, I will be checking with a few places around here to see if any of them have some old Tillys they wish to sell. If I can get them cheap enough, I'll stock up on them for future projects.

I just realized how stupid that just sounded... I hate spending money, but love spending money. :dizzy:
 
Thanks for that info.


I don't have a 19 or 103 on hand though.


What is the tillitson part number for the 19 or the 103 and the HL63???

I have seen a HL63d and a HL63e for sale. Is there a difference? If so what is it and would both work?
Thanks for your help! This will go on a Mcculloch 795 btw
 
Front tank saws like the 1-4X, 1-5X, 200, 250, 300, etc. used the HL63 with the stud in the top for the air filter cover. The letter suffix does not change the application or design of the carburetor. The 63 has a "self contained" choke mechanism as shown here.

DSCN3405.JPG

Top tank saws like the 1-7X, 1-8X, 740,790, 840, 890, etc. used the HL19 and 103 without a stud since the AF mount is an added piece that attaches to the air box.

DSCN0537.jpg

There were several different HL numbers that were used in each family of saws depending on the type of choke (front tank models) and whether the saw was fit with an air vane governor or not (top tank saws). There were a variety of the McCulloch Flat Back (Walbro) carburetors used as well, original in the 790 would have been a flat back with a primer. This one is equipped for the air vane governor.

DSCN0813.jpg

Aaron would probably know all the different Tillotson and Walbro numbers but he doesn't post on AS much any more as he's moved on to other sites.

Mark
 
That is very helpful information!

So I could use a the HL19, HL63e or HL63d and HL103. If it has the top bolt I wouldn't need to use the stock air filter bracket? Or cut it off if it doesn't line up!
 
If you use the 63, simply unscrew the stud from the top of the carburetor.

There some other differences among the HL models with bottom end, the fuel inlets, etc., some are "deeper" than others and will not fit some saws.

Again Aaron would be the one to know the differences but he doesn't spend much time on AS anymore.


Mark
 
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