McCulloch Chain Saws

[joeymt33]

Ok guys, this is really throwing me for a loop. Put the carb back together and back in the saw and same result. Swapped the carb from one of my good running 10-10s and same results so that eliminates the carb in my eyes.
To recap. The saw is rebuilt, NOS piston and rings, gaskets, seals. OEM kit in the carb. I have yet to get it to run "right" in order to get it to idle, I have to lean out the low so much that it bogs severely on acceleration, if I richen it enough to get rid of the bog, I cant turn in the idle screw enough to keep it idling. If I split the difference I can kind of get it to stay idling with a little throttle blip every now and then. Turn to the high needle. It seems to respond as I would expect. If I get it sort of right, and then make a couple of cuts with it, it goes lean with a racing idle etc. It is strange because on one hand, it acts like it doesnt want fuel, and on the other it acts lean. Also worth mentioning, might be, the exhaust fumes are so noxious they make your eyes water, I dont remember that from any other saws or sleds I've worked on and ive worked on a lot.
The only thing I havent really checked, because I lack a good way to do it, is the fuel line. I'm wondering if it has a pinhole or something. I also need to get a better setup for pressure testing. The setup I have I made years ago for checking sled engines, it runs on compressed air and is not really fine enough for saws.

Sorry for the long winded post, just hoping someone might have ideas for me.

Is the piston oriented correctly?

 

[2broke2ride]

Interesting thought, but yes.

I went out after supper and messed with the fuel line and ended up tearing it so I fabricated a temporary replacement.
No change, so I guess that rules that out.

 

[joeymt33]

Interesting thought, but yes.

I went out after supper and messed with the fuel line and ended up tearing it so I fabricated a temporary replacement.
No change, so I guess that rules that out.

I don’t remember what the symptoms were when I did that by accident one time but it drove me crazy until I figured out what I had done.

 

[fossil]

Ok guys, this is really throwing me for a loop. Put the carb back together and back in the saw and same result. Swapped the carb from one of my good running 10-10s and same results so that eliminates the carb in my eyes.
To recap. The saw is rebuilt, NOS piston and rings, gaskets, seals. OEM kit in the carb. I have yet to get it to run "right" in order to get it to idle, I have to lean out the low so much that it bogs severely on acceleration, if I richen it enough to get rid of the bog, I cant turn in the idle screw enough to keep it idling. If I split the difference I can kind of get it to stay idling with a little throttle blip every now and then. Turn to the high needle. It seems to respond as I would expect. If I get it sort of right, and then make a couple of cuts with it, it goes lean with a racing idle etc. It is strange because on one hand, it acts like it doesnt want fuel, and on the other it acts lean. Also worth mentioning, might be, the exhaust fumes are so noxious they make your eyes water, I dont remember that from any other saws or sleds I've worked on and ive worked on a lot.
The only thing I havent really checked, because I lack a good way to do it, is the fuel line. I'm wondering if it has a pinhole or something. I also need to get a better setup for pressure testing. The setup I have I made years ago for checking sled engines, it runs on compressed air and is not really fine enough for saws.

Sorry for the long winded post, just hoping someone might have ideas for me.

Since you've eliminated the carb and fuel line I'm wondering if you have an air leak between the tank / handle assembly and the cylinder. Maybe a bad gasket(s) or cracked insulator (spacer) under there.

The idle speed tabs often get bent up and should be parallel with the throttle shaft.

I future for testing a fuel line for holes or cracks, pull the filter and plug the line with a wooden pencil and blow in the other end. That should show up any leaks. I had one with about 8 pin holes in it. It looked like a tiny soaker hose.

PS, the piston orientation affects snagging the rings on a port or transfer.

 

[2broke2ride]

I actually have had the tank apart again since the rebuild. I found the DSP not sealing so took it all apart. This problem existed prior to that disassembly and still persists now.
All the gaskets where new at the time of the rebuild and still looked fine when I took it back apart.

 

[heimannm]

New projects this week.

Mini Mac 160S







I thought I'd give it a good cleaning & inspection.



I saw this one on e-Bay, thought it looked red. It didn't look like a repaint in the photos and in person it is actually orange and definitely not a repaint. I am curious as to how this one was labeled/branded as there are no indications on the saw now.







Mark

 

[hseII]

New projects this week.

Mini Mac 160S

View attachment 670703

View attachment 670704

View attachment 670705

I thought I'd give it a good cleaning & inspection.

View attachment 670706

I saw this one on e-Bay, thought it looked red. It didn't look like a repaint in the photos and in person it is actually orange and definitely not a repaint. I am curious as to how this one was labeled/branded as there are no indications on the saw now.

View attachment 670707

View attachment 670708

View attachment 670709

Mark

How does that 160S compare to a MS200T?

 

[heimannm]

I have only worked on one small Stihl saw, an 020 AVP and I will say the Mini Mac is much easier to take apart and put back together. Of course, I have a lot more practice on the Mini Mac saws and have a pretty good idea of where everything is supposed to go. Frankly, I don't mind working on these small McCulloch saws.

Mark

 

[rocketnorton]

+1 on cracked intake block, suggested by tim. had couple plastic poulans like that, pretty easy to break em, overtightnin carb.

 

[2broke2ride]

+1 on cracked intake block, suggested by tim. had couple plastic poulans like that, pretty easy to break em, overtightnin carb.

I had the one under the carb crack and it has since been replaced. I'm now wondering if the one under the tank is cracked and I missed it.

 

[PogoInTheWoods]

That orange Mini-Mac almost looks like Ridge Tools colors but I know they also re-badged a couple of the small top handle Poulans using their black and silver (gray?) color scheme. Don't know why they'd enter into deals with both companies for the same basic class of saw, tho. On the other hand, it also looks like Canadian Poulan colors which makes no sense either. Would certainly be interesting to find out who had them built.

 

[fossil]

Maybe an export saw?

 

[heimannm]

???

 

[fossil]

???

Many companies have moved production to other countries that have favorable duty structure if they want to move their products to other countries. Most times they had a free hand in producing what they thought would sell better.

 

[2broke2ride]

My newest project arrived today and I couldnt be happier, thanks again Mark.
It's a 1-86, 99cc gear drive. I couldnt help myself, I gave it a little prime down the carb and it fired in 3 pulls!!. In process of a major fuel system cleaning. Pics to follow in the near future.

 

[Jethro 2t sniffer]

Any luck with the 7-10 2broke? Put two tanks through my pm700 today and thanks to Mark its oiling great soo yea cheers Mark what a nice saw with a 20inch bar not too big but big enough for me. Got the 800 if need bigger but I'm finding the 700 to be my favorite saw most of the time. Next job is fix the decomp and a re ring its still very hard to bog down but yea must be a bit tired at this age. Was there ever many spare cylinders around? I think itle be ok but just curious.

 

[2broke2ride]

No, I put it on the shelf for the time being. I find when I'm getting frustrated at one it's best to just let it be for a little while. I have to get a better setup for pressure/vac testing. I'm fairly certain that its either an air leak or the strangest ignition problem I've ever seen.

Any luck with the 7-10 2broke? Put two tanks through my pm700 today and thanks to Mark its oiling great soo yea cheers Mark what a nice saw with a 20inch bar not too big but big enough for me. Got the 800 if need bigger but I'm finding the 700 to be my favorite saw most of the time. Next job is fix the decomp and a re ring its still very hard to bog down but yea must be a bit tired at this age. Was there ever many spare cylinders around? I think itle be ok but just curious.

 

[PogoInTheWoods]

A Mityvac 8500 is the way to go for a vac/pressure test setup. I bought mine for around $60 a few years ago. They're up to around $100 retail these days but I've seen them as low as $42 recently if you shop the online wholesalers. All metal. All parts are replaceable. Switches from vac to pressure with a small knob. Comes with a variety of adapters and plugs..., basically for a one-man brake bleeding setup. Indispensable in a saw shop and the first saw you save from burning up due to an air leak (or throw through a window cause you can't find an air leak) pays for it right there. Use it for testing carbs, tanks, hoses, etc.

 

[Scott Sonntag]

Thanks fossil, I will give "O" rings a try.

Another question for everyone, all I have left to do is hook up the fuel line to the carb and she's ready for a try. I received the saw with no bar and would like to run it with a bar so that the saw has resistance allowing me to tune it properly. My question being, is a pro mac 10-10 set up to run 3/8 pitch chain? I'm pretty confident the answer is yes but I am just wanting to double check.

 

[PogoInTheWoods]

Will obviously depend on the clutch sprocket, but typically, yes. Should be able to just wrap a piece o' 3/8's chain around the sprocket to confirm a matching pitch.