McCulloch Chain Saws

[heimannm]

The awl or pick is quite practical if you don't have the "needle". Sometimes it take two or three tries to get it through.

Mark

 

[mogulmasher]

Your right these old 80/87cc Macs always seem to have small bars around here. My 250 has just a 16" bar on it. Seems silly to me cause I'll only ever make cuts in big logs or noodle with it.

That 2-10 looks like it could be a runner. I've shelfed my 2-10 until shipping from Amazon and eBay speeds back up. Bullfrog in mine is clean as can be, I'm gonna throw a new diaphragm in it and can't see why it wouldn't run.

 

[2broke2ride]

@heimannm do you you have a write up on the bullfrog carbs? I would appreciate some info.

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[Jethro 2t sniffer]

Here ya Kevin.

https://www.arboristsite.com/community/threads/mcculloch-chain-saws.71126/page-204#post-2543631

 

[heimannm]

There is a thread on the 10 Series carburetors somewhere, if I get some computer time I'll see if I can find it again.

Mark

 

[edju1958]

I got the rope in place on the DE80 pulley & then pulled enough rope through to melt the end of it.It won't pull through the pulley for now,but I fear that over time it might.I tried to find the hole that the rivet was in & try as I might,I could not find it.
I had to put the project on hold for now due to my neighbor calling me yesterday to tell me he had some wood for me.Thre + hrs.of cutting & loading yielded 2 nice loads of cherry,maple,& box elder.Ihave to go back today to finish cutting up the main trunk.I used a saw with a 24 in.bar & had to come in from both sides to drop it,just to give an idea of the size of the tree.The electric.co.is supposed to come & drop another cherry tree that is causing problems with the wires going into the house.I'll most likely have at least 2 more good size loads of wood again.Tomorrow is supposed to rain & be windy for pretty much the entire day,so I might be able to get at that recoil then.
Ed

 

[PogoInTheWoods]

I received the new 7-10 cylinder from Bob J. today and am pleased to report that it's what I was hoping for..., iron bore three finger transfers like the original cylinder and included an 85239 thin ringed piston with rings as part of the 87681 assembly. (Guess that definitively answers the piston skirt question once and for all, eh?)

The only difference I notice between the cylinders is the casting of the intake and exhaust. No spacer required for the exhaust and the intake is more linear. Also of interest was finding how much obstruction there was at the intake from the spacer block/gaskets. Not sure how normal that is, but I'm certainly going to correct it somehow. Coupla bent fins that I'm not even gonna complain about! LOL

​

 

[PogoInTheWoods]

So now...., what is the recommended method of prepping the bore and piston for assembly and initial break in? There is some degree of oxidation in the cylinder, but not much. Would like to get rid of it, but certainly don't want to disturb the beautiful cross hatch in the process. Not quite sure how to go about doing it correctly.

 

[Jethro 2t sniffer]

So now...., what is the recommended method of prepping the bore and piston for assembly and initial break in? There is some degree of oxidation in the cylinder, but not much. Would like to get rid of it, but certainly don't want to disturb the beautiful cross hatch in the process. Not quite sure how to go about doing it correctly.

The green scrubby thing from under the sink? Don't get seen by the old lady.

Or is that too harsh?

 

[vinnywv]

Take a scrubby thing and use plenty of oil to gently take it off. It should not take any pressure. Then wipe clean with a rag.

 

[PogoInTheWoods]

That's along the lines of what I was thinking..., green Scotch-Brite pad saturated in oil until getting clean passes with a shop cloth or paper towel. I must say it feels a little bit rougher than a plated (or badly worn) cylinder. I'm gathering it's supposed to by nature for the "get acquainted" (seating) process between the rings and the bore.

 

[heimannm]

The iron bore cylinder were pretty hard (ever try to cut cast iron sewer pipe?) but the normal finish was a bit rough. It was most common to use chrome plated rings in order to maximize the life of the rings.

Chrome plated bores are very hard and very smooth so steel or cast iron rings are more suitable to allow the rings to wear a little to seat with the bore.

Mark

 

[2broke2ride]

I decided to go out and cut some with the 4-10. I made 2 cuts and realized I forgot my tuning screw driver in the garage. Walked back to the garage with the saw running in my hand, grabbed the screwdriver and headed back to the log pile. The saw died on the way to the log pile and i couldn't get it to restart. Back at the garage, spark would jump a spark plug but not my spark tester unless I spun the motor quite fast with my drill. I figured the chip died (have heard all the warnings) but wanted to try it anyway. So I cleaned up the original points and put them back I and gapped them. Had great spark. Put it back together and it fired right up. Great!! Had to go in for dinner, came out after dinner, saw fired but would die when I tried to rev it. Checked spark again and it is inconsistent unless I spin the motor fast with a drill. What am I missing here? Is this a coil issue? I've always had coils either fail or not.
Also, is this fuel cap repairable?

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[edju1958]

Kevin,try putting a new condenser in the saw.I'd bet any money that the condenser that's in it is weak or breaking down.It's rare that a coil will go bad,although they do on occasion.
As for the fuel cap,it almost looks like it's missing something.On an older Homelite there would be a small aluminum tube in the center with a duckbill under it.A Homelite fuel cap will fit on a Mac & work quite well.
Ed

 

[Maintenance supervisor]

I decided to go out and cut some with the 4-10. I made 2 cuts and realized I forgot my tuning screw driver in the garage. Walked back to the garage with the saw running in my hand, grabbed the screwdriver and headed back to the log pile. The saw died on the way to the log pile and i couldn't get it to restart. Back at the garage, spark would jump a spark plug but not my spark tester unless I spun the motor quite fast with my drill. I figured the chip died (have heard all the warnings) but wanted to try it anyway. So I cleaned up the original points and put them back I and gapped them. Had great spark. Put it back together and it fired right up. Great!! Had to go in for dinner, came out after dinner, saw fired but would die when I tried to rev it. Checked spark again and it is inconsistent unless I spin the motor fast with a drill. What am I missing here? Is this a coil issue? I've always had coils either fail or not.
Also, is this fuel cap repairable?

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Yes on the cap. Needs an insert tube with a duckbill valve.

 

[Maintenance supervisor]

Kevin,try putting a new condenser in the saw.I'd bet any money that the condenser that's in it is weak or breaking down.It's rare that a coil will go bad,although they do on occasion.
As for the fuel cap,it almost looks like it's missing something.On an older Homelite there would be a small aluminum tube in the center with a duckbill under it.A Homelite fuel cap will fit on a Mac & work quite well.
Ed

I second the condenser.

 

[2broke2ride]

This is a different type of cap, it had a duckbill up it the cap, turned to goo, I cleaned it all out. It looked like a larger duckbill like what would be in a large frame saw.
I dont know on the condenser, it acted exactly the same with the chip.

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[heimannm]

You should be able to pull the insert out of that cap and put a new duckbill valve in it.

Seems unlikely that your ignition problem is the coil, try a different spark plug and recheck the wiring and mechanism of the stop switch.

Mark

 

[2broke2ride]

View attachment 808958

You should be able to pull the insert out of that cap and put a new duckbill valve in it.

Seems unlikely that your ignition problem is the coil, try a different spark plug and recheck the wiring and mechanism of the stop switch.

Mark

Thanks Mark, where could one locate that large duckbill? Bob Johnson?

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[edju1958]

Also check your coil' is grounded properly
Ed