McCulloch Chain Saws

[Brian13]

Are you talking piston clearance or ring end gap.


Lee

I was talking about ring end gap.

 

[leeha]

I was talking about ring end gap.

Well, No ones perfect, Looks like i made a mistake.
For some reason i thought you talking piston clearance.
As for ring end gap, I don't really have a rule of thumb.
I usually try to keep them at around .008 but sometimes
even new rings will be a bit wider.
So i would say your .004 per inch would work fine.


Lee

 

[Ikeholt]

Mobetter,
I believe the condenser lead and the switch lead are on the top pair and the grounding lead is by itself on the bottom. There is probably a diagram posted somewhere. I probably have extra parts if you need them. PM me if you'd like, I'm Indiana also.

Tom

 

[mactodd]

I am working on a 7-10 and having problems getting it to run. It came to me with the small points eliminator module. My friend at work gave me the parts to convert it back to points ignition.

Question is: the coil has four taps, where does the lead from the condenser plug in? There was a grounding wire on one tap going to one of the coil mounting bolts, and of course the lead from the stop switch.

Can someone show me a picture or give me a brief explanation where the these leads go?

Thanks,

mo

It doesn't matter. They all connect to the ground side of the primary winding in the coil.
Just from a packaging standpoint, the wire from the points box goes on the bottom, and the kill switch goes to the top. The condenser should connect to the stud on the points box.

 

[Danno]

Just bought a Super 250 and had a question about it. I've looked everywhere, so if this is a total Newb question please forgive me. I've got the saw running fairly well, but the specs I'm finding on it indicate that it is an automatic oiler with manual override. I have the chain soaking in oil right now and have the bar mostly cleaned off, but they were pretty rusty, so I haven't run them on the saw yet.

My question pertains to the oiler system. what exactly does "manual override" mean? does it mean that I can either run automatic oiler or thumb pump it? OR does it mean that it will automatically oil, but when I press the manual oiler there will just be a little extra oil sent through?

I ask because my manual oiler is frozen, it appears to be solidly frozen down where the push rod goes into meet the piston, etc.

When I run the saw with no bar I'm not seeing a lot of oil buildup, so maybe my pulse pump is shot... any help would be appreciated.

If I could just get either the auto or the manual system going then i could play with the saw.

 

[a. palmer jr.]

Just bought a Super 250 and had a question about it. I've looked everywhere, so if this is a total Newb question please forgive me. I've got the saw running fairly well, but the specs I'm finding on it indicate that it is an automatic oiler with manual override. I have the chain soaking in oil right now and have the bar mostly cleaned off, but they were pretty rusty, so I haven't run them on the saw yet.

My question pertains to the oiler system. what exactly does "manual override" mean? does it mean that I can either run automatic oiler or thumb pump it? OR does it mean that it will automatically oil, but when I press the manual oiler there will just be a little extra oil sent through?

I ask because my manual oiler is frozen, it appears to be solidly frozen down where the push rod goes into meet the piston, etc.

When I run the saw with no bar I'm not seeing a lot of oil buildup, so maybe my pulse pump is shot... any help would be appreciated.

If I could just get either the auto or the manual system going then i could play with the saw.

You get extra oil when you pump it manually..it's for when you get into big wood which takes more oil. At least that's my take on it.

 

[heimannm]

The automatic chail oiler is operated off crack case pressure (differential) and is adjustable. If you remove the fuel tank cap you can see the adjuster screw and lock nut.

If the manual oiler is frozen, I would expect you have some advanced corrosion in the area and probably need to disassemble the whole thing to get it cleaned up and operating properly again.

Mark

 

[Danno]

The automatic chain oiler is operated off crank case pressure (differential) and is adjustable. If you remove the fuel tank cap you can see the adjuster screw and lock nut.

If the manual oiler is frozen, I would expect you have some advanced corrosion in the area and probably need to disassemble the whole thing to get it cleaned up and operating properly again.

Mark

Thanks Mark (and a. palmer jr.). I've got the saw tilted right now and that push rod sprayed with PB Blaster. I had cleaned the area with carb cleaner and read that the o-ring can lock it up when you do that, but it feels locked tighter than an o-ring should do. I'll check it out after work tonight, maybe play with the oiler adjustment, and then see where i need to go next.

I wasn't really in the mood to disassemble anything, because I don't have a great bench for it right now. I've got a shed I need to get finished up before I have a good saw workbench again.

Maybe this will be a good project for this winter and I can take the whole thing apart and paint it all nice-like. After cleaning it up, the saw is looking pretty darn good. Sure it shows wear, but it is a tool, after all!

 

[heimannm]

I am working on a 7-10 and having problems getting it to run. It came to me with the small points eliminator module. My friend at work gave me the parts to convert it back to points ignition.

Question is: the coil has four taps, where does the lead from the condenser plug in? There was a grounding wire on one tap going to one of the coil mounting bolts, and of course the lead from the stop switch.

Can someone show me a picture or give me a brief explanation where the these leads go?

Thanks,

mo

Actually there is one terminal with two connectors for the primary side of the coil winding, one ground lead, and one seconday lead to the spark plug.

The wire from the points/condensor should connect to the primary windings of the coil, and the ground lead is the one with the wire to the coil mounting post.

The seconday windings will show 2-5k ohms between the spark plug lead and ground, the primary windings will only be 2-3 ohms from the terminal to ground.

This photo is not quite as good as it could be since you can't see where the ground lead exits the coil, but it does show the primary lead connectred to the points/condensor, and the kill switch connection that simply grounds the primary side to stop the engine.

Mark

 

[knockbill]

mac 250...

i picked up a mac 250 last weekend, (posted pics in thread "my new saw"),,, and since have been reading and trying to get teh mac 58856b carb to work right. i read heimannm 's thread on mac carbs, but it seems teh cost of a kit for it is pretty steep,,, the saw is in very good condition overall, and looks hardly used, so, i'd like to get it working right, even if it means changing to a different carb,,,anybody have experience with that? or any other suggestions?
thanks in advance,,, i thought i could get more help here than the general forum,, its my 1st mac!!!!!!!!

 

[briantutt]

i picked up a mac 250 last weekend, (posted pics in thread "my new saw"),,, and since have been reading and trying to get teh mac 58856b carb to work right. i read heimannm 's thread on mac carbs, but it seems teh cost of a kit for it is pretty steep,,, the saw is in very good condition overall, and looks hardly used, so, i'd like to get it working right, even if it means changing to a different carb,,,anybody have experience with that? or any other suggestions?
thanks in advance,,, i thought i could get more help here than the general forum,, its my 1st mac!!!!!!!!

You know the rules. If the pics aren't here you don't have it...

 

[knockbill]

mac 250

fair enough,,, here are the before pics,, again....

 

[knockbill]

mac 250, more pics

heres some more pics,
thanks...

 

[ric5141]

Knockbill, the saw looks good and so does the vette!

 

[knockbill]

Knockbill, the saw looks good and so does the vette!

ok,, thanks,,, but what about gettin the saw running??

 

[turtle561]

[IMGhttp://www.arboristsite.com/attachment.php?attachmentid=153015&stc=1&d=1286234941[/IMG]

try a tillotson HL carb. it solved my problems with a balky mac flatback. you'll need one with the low profile intake to get the clearance that is needed. here's a few pics to show the difference.

from top to bottom:
low profile HL intake
regular HL intake & flatback
low profile HL intake & flatback
all three for comparison

 

[knockbill]

"try a tillotson HL carb. it solved my problems with a balky mac flatback. you'll need one with the low profile intake to get the clearance that is needed. here's a few pics to show the difference."

thanks for teh reply....
will the hl tilley fit without any mods to the saw? do i need to find different linkage or fittings? i guess teh tilley needs choke linkage to replace teh mac primer,,,,

 

[turtle561]

knockbill- it will fit right in there. the HL is about 1/8" shorter front to back. in my case i just rebent the primer linkage and was good to go. i did have to flip the choke shaft & lever from left to right to get the push of the thumb to close the choke.

 

[8433jeff]

HL's are way simpler, no more voodoo dolls/saws and McCulluchan hat dances to start your saw. Whatever work you do to make it fit, you'll save time and frustration later. Thats what I did with the Disston.

 

[Eccentric]

Eliminate the governor on a McCulloch 790?

Well, as of this weekend, I now have two McCulloch 790's in my possession. One is RandyMac's, and the other one Randy gave me to keep/fondle/restore/gaze-lovingly-at in exchange for restoration work on his 790. Works for me. Thanks Randy!

Anywho.............one 790 (Randy's) has a primer-flatback, while the other has a Tilly HL (An HL19E). The saws have minor cosmetic differences, such as kill swith color and material (one's yellow painted metal, while the other's plastic). One has "790" stamped into the end of the 'post' on the bottom of the block, while the other has "790" stamped in the block to the left of said 'post'.

Both saws have air vane governors, with the carb's throttle arm only having one 'leg' that is pulled closed by the trigger. The other end of the throttle shaft is controlled by the forked arm of the air vane governor. It's exactly as pictured in Mark H's Flatback thread. The Tilly HL is either original equipment for my saw, or was swapped in from another governor equipped HL carb'd Mac such as a D44. I saw in Mark's Flatback thread that the later 795 had no governor, and the carb throttle arm had two 'legs' on it...........one to be pulled closed by the throttle link, and the other to be pushed open by it.

My question is this; Can we remove the air vane governors and run the saws without them (without further modifications), or would we need to have a throttle arm/shaft setup like a 795 or 797 for things to work right? Randy probably has another flatback throttle arm (or complete flatback) with the later style non-governor 'two-leg' arm that I could swap onto his saw if need be. I have a Tilly HL63E on a Mac 200 (Randy's parts saw) that I could rob the throttle arm or shaft from and swap into the HL19E (or just swap the whole carb) on my 790 if needed to make things 'right' for non-governor operation.


I'll be pouring over IPL's for these 790 saws soon. Won't be able to tear into them until I get the carb sqared away on my McCulloch 77 for Mark. One thing at a time. Randy gave me a bar adjuster/clamp assembly for the 77 this weekend, and Brad M. sent me a pair of bar studs and a bumper spike for it (from Canada no less)..........so I'll be able to pass that beast on to Mark soon. Thanks guys!