Mac 795 Tilly swap

So, I got this 795 back in the spring. I finally got around to getting it going (or trying to, anyway).

The thing refused to run at all with the flatback carb. Now, let me say here that I haven't got anywhere near the experience many of you do with them, but I have yet to master any McCulloch carb. So, out it was going to go and in would go a Tillotson HL.

I pinned down an HL 63 that would fit, but had problems of it's own (broken off fuel line nipple). Next, I got an HL-19. This is the same carb as in my 1-82.


I got the HL-19 bolted in with the original 795 throttle linkage.


2 problems arose. First, at full trigger travel, the throttle plate was only open about 80%. Second, as the throttle rod moves forward, in the last couple of hundredths of travel, it rotates upward toward the air filter allowing the blade to slide past it. The HL-19 as set up for a governed saw has a barrel spring on the shaft that, unconstrained, sets the throttle wide-open, a dangerous situation. As set in the 1-82, it works great.


For more on the governor, watch this... www.youtube.com/watch?v=MShUknANczg

In addition, my HL 19 was lacking the idle speed control screw and extension bracket. No trouble, since I have the HL-63 sitting there, so I swapped the throttle rods to get the captive plate as well as the idle speed control. I put a carb kit in the HL-19 and bolted it in. I had to bend the throttle rod over just a little at the elbow to line everything up properly. Since there is no "S" in the thottle rod at the carb to make it a totally captive setup, I'd like to find a barrel spring to put on the shaft to close the throttle if it slips out, but I'll work on that later.



The choke linkage is from a D44 and it isn't quite long enough to close the choke. I have some heavier wire around, I may just make one later.

So, does this beast run?


I tried pulling the cord several times with the cover off to access the idle screw and check things over. No dice (typical). I quit to check the spark (it was good) and blow it out to avoid flooding. At this point I notice gas was ponding under the carb... Hmmm. I pulled the carb out and it is dry, then I noticed a couple of dry-rot cracks in the fuel line. When I tried to pry it off the carb, it broke all together.

Here comes the begging. Anyone have a fuel line for this saw that they would sell me?

Nice project.
As for the fuel line, You can try
Bob"s lawnmower in NY
or Discount Marine in MI.
You should be able to find it at one
or the other.
If you need contact info let me know.
I also have the IPL if you need part #


Lee

Thanks Lee, I'll call Discount Marine in the morning.

They should be able to help.
If not let me know and i can
give you Bob's number as well.

Do you have the part number?


Lee

I'm at work right now... but my 797 has an HL19E swapped into it from the original Flatback... I'll take some pics for you later on tonight or tomorrow...

The primer rod from the flatback was bent to accept the HL choke linkage... and the throttle linkage is bent in a way that the throttle will not go to WOT. So I gots to do some tinkering with it.

It also has the governor stuff still on it... But the saw will run and cuts just fine... Just needs to be "tweaked" a little. I received the saw this way when I bought it.

I'm also in the process of swappin' out the Flatback out of my 640 for an HL63 I got from Jacob J. Haven't got to tear into that one as much as I want to yet... so it's still a work in progress.

Gary

Post man made my day. A new fuel line and filter arrived. Thanks Lee for the tip on Discount Marine. They impressed me greatly. They're a fine resource for NOS Mac parts. It cost half for both together what just the fuel line ran me on the 288xp.



Now I have to rush through chores and muster the strength to tough out a COLD shop and put it together.

Me thinks it won't happen tonight. The FIL's English Setter and I are going to huddle up and at least one of us is going to tuck into some bourbon and enjoy a good book instead.

Do keep us posted. Lots of good info here. Gives me inspiration to get working on a couple old MACs I've got.

I say put the book down, have some bourbon,
grab the setter and let him watch you get the saw running.

Glad i was able to help. Now lets see some chips fly.


Lee

Get after those saws! I've had to pass on a 1-72 and a Super 44 I've wanted due to economic circumstances recently. I'd dearly love a hot 1-72 to match my 1-82. I know how mine goes, it's a full-tilt hot rod. I hope to get it going by the weekend and have a RWYB race between the 795, 1-82, 288xp, and 372xp in some big wood if I can get something 20" or better out of the pile.

URGE TO KILL RISING!!!

I have to admit shame... and order another fuel line.

I spent over an hour trying to get the "grommet" portion through the tank wall. I used Tri-Flow, oil, 2-cycle oil, dish soap, needle nose pliers, various picks, probes, and screwdrivers and ultimately, the sharp aluminum edges of the tank pass-through cut it. :censored::censored::censored::censored::censored::censored::censored:

Any ideas on how to get one in without damage? And don't say patience, 60 minutes plus of coaxing is enough.

GUH, I'm frustrated.

I think Discount Marine is going to be thrilled with me, though:monkey:.

Which way did you try to put it though.
i think it is meant to go one way.
Ether from the tank out or air box into tank.
There are the bumps in the fuel line but one
is bigger than the other, I believe.


Lee

leeha said:

Which way did you try to put it though.
i think it is meant to go one way.
Ether from the tank out or air box into tank.
There are the bumps in the fuel line but one
is bigger than the other, I believe.


Lee

Click to expand...

This was my thinking too.

Yes, from tank to carb well is the only way...

OK, Fuel Line Round 2 and I'm losing.

I have the thing coated in grease and cannot get it even started through the passage from either direction. I do not want to break this one.

Any ideas how the :censored: to get one of these in?

Otherwise, I'm firing up the dremel and "porting" the fuel line passage!

When I encountered a similar situation, I enlarged the hole a bit: problem solved.

Mark

I have never had a problem.
IMO i would not open the hole then it
might leak. I use STP for a lube because
it is slicker than snot on a door knob.
Also some of the earlier 790, 795's had a
screw in fitting with a hose in the tank and
a seperate host to the carb. This fitting being
screwed in the tank from the air box side.
If you have threads in the hole then it must
have had the fitting.


Lee

When doing my sp 81, which has the same type fuel line, I took a drill bit that i could shove in the carb end & thread it through the tank and grab the bit then grab the line with some tiny needle nose pliars. then it was just a matter of pulling the line through and seating it correctly.

I did not use a new line though so they could be tougher to deal with..

Smooth bore Lee.

056 kid said:

When doing my sp 81, which has the same type fuel line, I took a drill bit that i could shove in the carb end & thread it through the tank and grab the bit then grab the line with some tiny needle nose pliars. then it was just a matter of pulling the line through and seating it correctly.

I did not use a new line though so they could be tougher to deal with..

Click to expand...

Did you use the drill bit as a sort of mandrel inside the fuel line?

Guess I need smaller needle noses, the 2 I have are too big to even protrude through the far end of the hole.

Dremel wins!!!

I reached through the fuel filler hole and slightly, gently, radiused the passage without enlarging it. Blew eveything out with the compressor (I have an extra new filter from the one I broke), regreased and it is IN!!! Who says nose sprocket grease is a waste?!?

or some fine bourbon...

I'll try to fire it tonight, but won't make it to the wood pile until Thursday most likely.

Congrats Buddy,
I knew you would get it.


Lee