McCulloch Chain Saws

[8433jeff]

I agree. I was extremely lucky with both of my 250 Macs. .

And the fact nobody tried or made you take a, some, or all the Minimacs laying around.

 

[promac850]

Here's one that has got me mystified. Working on my Super 250. Very poor spark, hard to start, won't idle, cuts out upexpectedly. Installed new points and condensor, set coil air gap, still poor spark. Barely jumps a 1/16" gap, not even close to 1/8" or 1/4". Filed and cleaned the new points and swapped condensors, no improvement. Swapped coils, no difference. Reset the points gap just a hair tighter, much better spark but not at fast cranking speeds. Spinning the flywheel by hand produces a great spark that jumps a 1/4" gap and I can hear it, but when I crank with the recoil it vitually disappears. Predictably, it won't run this way. Very poor idle and if I hit the throttle it'll miss and sputter. Sometimes it'll catch and rev up, but there is still a severe miss.

So, I can put in an electronic module but this would be pretty much admitting defeat. Do I need to keep adjusting the points tighter? Factory spec is .020. I've already disconnected the on/off switch so that has been ruled out.

Chris B.

Baffling. I assume all of the connections are perfectly clean, and all of the parts are good. Hmm... just for the heck of it, go tighter with the points, maybe the new parts are 'tighter' than what was made years ago. My slightly experienced 2 cents.

 

[a. palmer jr.]

Here's one that has got me mystified. Working on my Super 250. Very poor spark, hard to start, won't idle, cuts out upexpectedly. Installed new points and condensor, set coil air gap, still poor spark. Barely jumps a 1/16" gap, not even close to 1/8" or 1/4". Filed and cleaned the new points and swapped condensors, no improvement. Swapped coils, no difference. Reset the points gap just a hair tighter, much better spark but not at fast cranking speeds. Spinning the flywheel by hand produces a great spark that jumps a 1/4" gap and I can hear it, but when I crank with the recoil it vitually disappears. Predictably, it won't run this way. Very poor idle and if I hit the throttle it'll miss and sputter. Sometimes it'll catch and rev up, but there is still a severe miss.

So, I can put in an electronic module but this would be pretty much admitting defeat. Do I need to keep adjusting the points tighter? Factory spec is .020. I've already disconnected the on/off switch so that has been ruled out.

Chris B.

You might have a bad ground somewhere. Might try scraping a few terminals and places where wires make contact.

 

[dieselsmoke]

Well that big orange ball appeared in the sky this AM, I might have to go cut some firewood. I played with the "Idle govenor spring" on the 790 last nite and I think I got it. I'll actually get to run a tank or two thru that saw, first time since I got it. I had to rob parts from the 740 to make a complete rear handle and bottom brace.
The 740 needs a carb kit, so It's on the shelf anyway.
The 790 ready and waiting:

I bet this will cut:

there, no more red X's

 

[promac850]

Umm... do you need the tank assembly on that 790 there Diesel? I can has it?

In all seriousness, I do need a tank, complete with baffles, etc.

I went out to play with the newly reborn Ryobi SS30 trimmer, and holy mackerel, this thing needed that muff mod and porting... this 30cc trimmer absolutely kicks ass now. You hit the throttle and the thing torques about 60 degrees to the right. uttahere2:uttahere2:

So much for calling that thing a POS...

 

[dieselsmoke]

Mac Parts

Hey 610, I am going to see my buddy in Amboy about a parts donar saw, 700 series. I'll hook ya up with the cases , tank, ect. once I get the Parts I need. Why dont you make up a list of the pieces you're missing and pm me.

 

[promac850]

Hey 610, I am going to see my buddy in Amboy about a parts donar saw, 700 series. I'll hook ya up with the cases , tank, ect. once I get the Parts I need. Why dont you make up a list of the pieces you're missing and pm me.

Cool, will go check the parts that I have. I should have a complete list of exactly what I need soon. You guys rock!! :yourock:

Just to tickle me happy, what's the biggest bar you can run on a 790 in hard wood and soft wood?

 

[dieselsmoke]

Randy knows, He actually ran these saws in the big ol wood, back in the day.

 

[RandyMac]

Six cubes, 42", fear no evil.

 

[Brian13]

Here's one that has got me mystified. Working on my Super 250. Very poor spark, hard to start, won't idle, cuts out upexpectedly. Installed new points and condensor, set coil air gap, still poor spark. Barely jumps a 1/16" gap, not even close to 1/8" or 1/4". Filed and cleaned the new points and swapped condensors, no improvement. Swapped coils, no difference. Reset the points gap just a hair tighter, much better spark but not at fast cranking speeds. Spinning the flywheel by hand produces a great spark that jumps a 1/4" gap and I can hear it, but when I crank with the recoil it vitually disappears. Predictably, it won't run this way. Very poor idle and if I hit the throttle it'll miss and sputter. Sometimes it'll catch and rev up, but there is still a severe miss.

So, I can put in an electronic module but this would be pretty much admitting defeat. Do I need to keep adjusting the points tighter? Factory spec is .020. I've already disconnected the on/off switch so that has been ruled out.

Chris B.

Could be broken strands in a wire, or maybe the lead itself. I would check and or replace the wire going from the points to coil.

 

[promac850]

Six cubes, 42", fear no evil.

uttahere2:uttahere2:uttahere2:uttahere2:

Awesome!!!!!!

 

[cbfarmall]

Could be broken strands in a wire, or maybe the lead itself. I would check and or replace the wire going from the points to coil.

I thought of that. After glancing at my Nova module and seeing that it had a wire with the bullet style terminal to fit Macs, I just had to install it. Saw fired, idled, roared on the first pull. When I get motivated, I'll pull the flywheel and investigate again. Meanwhile, my very next project will be to put new bearings in my other Super 250. Depending on weather, tomorrow may be the day.

Chris B.

 

[Eccentric]

That's what I thought as well but I'll have to do some investigating to be sure. The clutch cover does not have a starter and the clutch has no starter pawls. I found something interesting when I was looking through some of my info.

Apparently McCulloch made a 740L model. It is listed in the '68 Piston, Cylinder Assembly, & Ring Set data sheet. It says that it was a European model and had the thin rings. I'll have to check and see if this one is thin or thick rings. Could be a frankensaw or could be a rare model.


I don't have an IPL for a 740L but I do have one for a 795L. I wonder if the starter/flywheel/clutch/clutch cover from one of these could have been switched over to a regular 740?

Oh, and it does have the Mac carb with primer. 59346C is stamped on the carb.

Nice. I remember seeing that saw in the classifieds ad. Your AF cover doesn't read "740L"......but then of course it could have been swapped. You could still have a 'real' 740L. My money's on the saw being a frankensaw however. I was going to do that same swap on my 790. Changed my mind and decided to leave it RH start instead...

I've never seen pics of an 'L' model 700-series Mac with a black starter housing. I've seen those starter housings on later 250's and other front-tank LH start Macs.

The clutch cover looks like what you'd find on a non-chainbrake 105 or 125 Mac. The flywheel cover on most (if not all) saws in this series have the bosses to support a LH starter housing (and mounting hardware) cast into it.

A fellow needs only to snap out the grill and drill the three holes for the scews in order to make the cover take a Mac LH starter housing and screen. A flywheel from most LH start Macs could be swapped on, as could a non-RH start clutch assembly.

The 1-92 'two man' saw, as well as the welders that used this engine had that same flywheel cover with a LH start type starter housing on it. I always smile when I see the falling site line cast into the starter housing on a McWelder.:msp_biggrin:

Looks to me like you're going to need a new tank top, unless there's unbroken metal under the glob of epoxy (or whatever that is) on the LH side.

I have just acquired a lot of mcculloch nos parts, we are talking boxes and boxes of parts and i have no way of knowing what part numbers go to what saws is there a site that has a way to type in the part number and it tells you what saw it goes to, when i get all of the parts organized let me know if any body needs anything will sell real cheap, i got this lot cheap from a local mower/saw shop and would pass on the savings.

email [email protected]

Oh crap. I'll be in touch. There's a buncha McCulloch parts that I need...

Here's one that has got me mystified. Working on my Super 250. Very poor spark, hard to start, won't idle, cuts out upexpectedly. Installed new points and condensor, set coil air gap, still poor spark. Barely jumps a 1/16" gap, not even close to 1/8" or 1/4". Filed and cleaned the new points and swapped condensors, no improvement. Swapped coils, no difference. Reset the points gap just a hair tighter, much better spark but not at fast cranking speeds. Spinning the flywheel by hand produces a great spark that jumps a 1/4" gap and I can hear it, but when I crank with the recoil it vitually disappears. Predictably, it won't run this way. Very poor idle and if I hit the throttle it'll miss and sputter. Sometimes it'll catch and rev up, but there is still a severe miss.

So, I can put in an electronic module but this would be pretty much admitting defeat. Do I need to keep adjusting the points tighter? Factory spec is .020. I've already disconnected the on/off switch so that has been ruled out.

Chris B.

That's a strange one Chris. The strangest part is that you get a great spark by hand-spinning the flywheel (I assume with the plug out), but get a weak spark when pulling the saw over with the recoil. If the spark was always weak, I was going to suggest you swap flywheel's..........on the off-chance that the magnets were shot.

Maybe the flywheel side crank bearing is shot and the crank and flywheel are moving away from the coil laminations when the saw is pulled over using the recoil. Just a S.W.A.G....opcorn:

And the fact nobody tried or made you take some, or all the Minimacs laying around.

There were thankfuly no mini-macs around when either of those 250's came to me Jeff. I did have to take an ugly Mac-120 as part of a freebee batch of saws that also included three XL12 family Homelites and a Remington/Wards saw however. You want it?:jester:

 

[promac850]

Nice. I remember seeing that saw in the classifieds ad. Your AF cover doesn't read "740L"......but then of course it could have been swapped. You could still have a 'real' 740L. My money's on the saw being a frankensaw however. I was going to do that same swap on my 790. Changed my mind and decided to leave it RH start instead...

I've never seen pics of an 'L' model 700-series Mac with a black starter housing. I've seen those starter housings on later 250's and other front-tank LH start Macs.

The clutch cover looks like what you'd find on a non-chainbrake 105 or 125 Mac. The flywheel cover on most (if not all) saws in this series have the bosses to support a LH starter housing (and mounting hardware) cast into it.

A fellow needs only to snap out the grill and drill the three holes for the scews in order to make the cover take a Mac LH starter housing and screen. A flywheel from most LH start Macs could be swapped on, as could a non-RH start clutch assembly.

The 1-92 'two man' saw, as well as the welders that used this engine had that same flywheel cover with a LH start type starter housing on it. I always smile when I see the falling site line cast into the starter housing on a McWelder.:msp_biggrin:

Looks to me like you're going to need a new tank top, unless there's unbroken metal under the glob of epoxy (or whatever that is) on the LH side.



Oh crap. I'll be in touch. There's a buncha McCulloch parts that I need...




That's a strange one Chris. The strangest part is that you get a great spark by hand-spinning the flywheel (I assume with the plug out), but get a weak spark when pulling the saw over with the recoil. If the spark was always weak, I was going to suggest you swap flywheel's..........on the off-chance that the magnets were shot.

Maybe the flywheel side crank bearing is shot and the crank and flywheel are moving away from the coil laminations when the saw is pulled over using the recoil. Just a S.W.A.G....opcorn:



There were thankfuly no mini-macs around when either of those 250's came to me Jeff. I did have to take an ugly Mac-120 as part of a freebee batch of saws that also included three XL12 family Homelites and a Remington/Wards saw however. You want it?:jester:

I like them XL-12's. Do they all run and cut? Sounds like a fun trio of saws.

 

[cpr]

Cool, will go check the parts that I have. I should have a complete list of exactly what I need soon. You guys rock!! :yourock:

Just to tickle me happy, what's the biggest bar you can run on a 790 in hard wood and soft wood?

I have the heat shield and screws that go under the tank for you. I'll try to remember to ship them out on Monday. I also think I have my reed block configuration figured out for the 101, so I'll send that to you, too. Block, reeds, retainers...

 

[Eccentric]

I like them XL-12's. Do they all run and cut? Sounds like a fun trio of saws.

Not to derail this McCulloch thread too much........but none of those three Homelites that came in that group turned out to be runners. Same with the Remington unforunately. They're all parts saws with scored P/C's. One's a great looker, and will be getting a good used P/C from a butt-ugly (though great running) SXL12 that I already had. Aside from that looker XL12, the best thing to come from that group was all the spare carbs, castings, bars, rim drive drums, and other good parts I got from those saws......without having to spend a dime or even drive very far.

Got a 20" roller nose, a 20" hardnose, and a 24" Windsor Speed Tip replacelable sprocket-nose out of that group. All were wearing safety chain however. That's not something you see on a Speed tip or an old Roller Nose very often...:cool2:

The Mac120 that came in that group has just about everything 'needed' to complete the 120 basket case I already had........except for a couple of gaskets and a carb kit. Those are EXTREMELY low-priority however. They do suffice for Mac content however.:jester:

 

[promac850]

I have the heat shield and screws that go under the tank for you. I'll try to remember to ship them out on Monday. I also think I have my reed block configuration figured out, so I'll send that to you, too. Block, reeds, retainers...

Awesome!! Looking forward to a box dropped on the steps.

I am loving the idea of pulling a 40 or so inch bar on the 790... and for small stuff, a 24 inch bar... uttahere2:

 

[joe25DA]

1-10

I picked this one up today. Little history on it for you guys. Its a one owner saw bought back in 1966. I got it from the orig owners son. He hadnt used it in 15 years but held on to it for sentimental reasons. He even had the orig manuals. He sold it to me cause he knew I appreciated what a good saw it was. It was taken care of as seen from the pics. It has 135 psi, but no spark. Im thinkin a little cleaning on the points will fix that. It also has that crazy carb on it which my 2-10 has as well. Any info on those?
I paid $30 for it and I think I got a good deal. This will be a fun project along with that 1-42.
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[struggle]

I dug into the SP 125 tonight and removed the fuel tank and took the top part of the oil pump off and nothing looks bad there.

Clearly the oil pump itself is OK on the top as the little piston deal moves fine and the disk it appears all good.

So do I remove the oil tank itself to help determine why it is leaking back into the block? I am going to look at the ipl a little but I see no other way to resolve it without removing the tank itself and once I do what am I looking for? Are gaskets for these still available or am I somehow going to have to make a tank gasket and such?

On a good note the crank bearings have no play in them up and down or side movment. I am happy with that.

THe hack fuel tank repair though is clearly not working as I had poured some fuel in it and it appears to be seaping to no surprise.

 

[8433jeff]

There were thankfuly no mini-macs around when either of those 250's came to me Jeff. I did have to take an ugly Mac-120 as part of a freebee batch of saws that also included three XL12 family Homelites and a Remington/Wards saw however. You want it?:jester:

I'll pay the shipping.







You have to take the ones I cleaned up (kinda) the other day, theres a grass catcher bag full of tins, frames, clutch covers, handles and gas tanks. Then theres the orange box sized box of motors and complete saws, a small stack of bars I scrapped, and the overflow-only 2-3 more saws. There were as many of them as there are other saws combined. I won't send these Priority, but they are coming COD.:cool2: