McCulloch Chain Saws

[Jeffrey F.]

well I have material on order for the fuel pump Diaphragms #36235 at $200 a square yard you guys better buy a crap load

 

[sawfun]

I got my Mac 650 in the mail today & was quite satisfied at the condition it's in.It doesn't look like it's had a lot of use.The seller said that it'd probably need to have the carb gone through.I've found that most folks don't know how to start an old Mac by using the primer.First thing I did was pull the fuel line out only to find that there was no filter on the end of it.I put a filter on & some fuel in the tank & tried starting it.It'd run on a prime,but then quit.I then checked the needles to find they were way out of whack (I should've done that to begin with).I put more fuel in the tank & primed the carb twice,the primer doesn't work.After the 2nd prime it was running beautifully.It ran so dang good that when I went to shut it off it just kept running.I tried to choke it out by covering the air intake on the carb,but there must've been just enough air getting by to keep it running.I thought about pulling the fuel line out of the tank,but don't like it when the saw leans out.Finally I turned the idle screw out so that it couldn't idle anymore.I pulled the recoil off to find there was no wire going from the switch to the coil.I had an old point to coil wire from the 450 on hand & it fit the bill.
This saw is a beast at 87cc & gear drive.I'm not sure what pitch the sprocket is.Maybe someone can tell by the pic? I hope it's not a 7/16 or 1/2.
Edit:I just looked at the IPL & it looks like the 650 & 660 came with 1/2 in.sprockets.I hope Mac made a .404 sprocket for these saws.

.404 skip chisel worked great on my 660 with 36" bar.

 

[Syncop8r]

My 2-10 will pop but won't run. I've tried the low jet on 1, 1&1/4 and 3/4 turns out but no luck. There's a little bit of fuel in the airbox.

I realize it could be any of a number of things but any idea what to try first?

 

[matt_lamb_160]

Is the plug wet? If it isn't, you could try priming it by tipping a bit of fuel down the carby. If it runs, you have a carb issue, an air leak or a fuel line leak. Do you have a pressure/vacuum tester?

 

[matt_lamb_160]

 

[Syncop8r]

Is the plug wet? If it isn't, you could try priming it by tipping a bit of fuel down the carby. If it runs, you have a carb issue, an air leak or a fuel line leak. Do you have a pressure/vacuum tester?

No, I don't.
I'll check the plug next time.
Thanks!

I went on a firewood mission today and my normally reliable 610 wouldn't oil either way, then something happened to the chain brake that will require attention... so I currently have no operational Macs.

 

[matt_lamb_160]

While the plug is out you might as well check the spark too, ground the base of the plug to the block and pull it over.

 

[Syncop8r]

While the plug is out you might as well check the spark too, ground the base of the plug to the block and pull it over.

I did that after I worked on the points.
It pops and runs for a second or two.

 

[Maintenance supervisor]

I did that after I worked on the points.
It pops and runs for a second or two.

Time to go through the fuel system.

 

[Maintenance supervisor]

I did that after I worked on the points.
It pops and runs for a second or two.

Time to go through the fuel system.

 

[Maintenance supervisor]

Don't understand why it multiplied?post

 

[Syncop8r]

Don't understand why it multiplied?post

Perhaps it thought it was a really important point.

 

[Jethro 2t sniffer]

No, I don't.
I'll check the plug next time.
Thanks!

I went on a firewood mission today and my normally reliable 610 wouldn't oil either way, then something happened to the chain brake that will require attention... so I currently have no operational Macs.

I know the feeling . My 81 not well. I pulled carb out n then couldn't find my bag of kits from Ed so I pulled it down n cleaned it out n nah no better or now even worse. The low is all over the show now. Thought I'd tinker with the oiler too and nup no auto n miserable manual. I gave it a couple turns on the pump I swapped out the cap for a dribbler that breaths. No change

The sp70. Other than won't idle for long is a grunt box. My best 70 yet I think but.... its not oiling well either.

This week I'll yank the pumps n dung em out n hopefully find Eds kits or swap in runner 44s from parked 700s

Old reliable 800 will come out next weekend with the 32.

Did I mention I love that SP70

Funny thing with those pumps they all behave differently no matter where the adjuster is. And I have 5 or 6 that pump great in the hand yet won't pump didly in the saw and the 850 doesn't care for any pump lol

 

[Syncop8r]

Hey Jethro... do you love your SP70?

 

[sawfun]

Nice, I count a bit over 500cc's of Mac there.

 

[bob kern]

No, I don't.
I'll check the plug next time.
Thanks!

I went on a firewood mission today and my normally reliable 610 wouldn't oil either way, then something happened to the chain brake that will require attention... so I currently have no operational Macs.

Now that is a crisis!!!!

 

[edju1958]

Jethro,on those auto oilers - ya need to pull the pump out & check to see if the piston moves up & down freely.If it's sticking,then ya need to take the piston out & use a fine croakus cloth to lightly sand the edge of the disc.Bob Johnson gave me that advice a few yrs.back.I can't tell ya how many pumps I got working again by doing that.Another thing could be a sticky/stuck check ball.Don't take that part of the oil pump apart,just spray some carb cleaner in it & it should free it up.

As for your manual pumps not working,there's not really much to 'em.It could be the O ring on the plunger is worn out.There also has to be the check valve disc in place that goes under the pump & the gasket has to be sound & form a good seal.Another thought is to have the correct disc.The older saws with the metal pumps used a fiber disc & the newer plastic pumps used an aluminum disc.

You still have carb kits that I sent you?I thought you used 'em all by now!

 

[Jethro 2t sniffer]

Jethro,on those auto oilers - ya need to pull the pump out & check to see if the piston moves up & down freely.If it's sticking,then ya need to take the piston out & use a fine croakus cloth to lightly sand the edge of the disc.Bob Johnson gave me that advice a few yrs.back.I can't tell ya how many pumps I got working again by doing that.Another thing could be a sticky/stuck check ball.Don't take that part of the oil pump apart,just spray some carb cleaner in it & it should free it up.

As for your manual pumps not working,there's not really much to 'em.It could be the O ring on the plunger is worn out.There also has to be the check valve disc in place that goes under the pump & the gasket has to be sound & form a good seal.Another thought is to have the correct disc.The older saws with the metal pumps used a fiber disc & the newer plastic pumps used an aluminum disc.

You still have carb kits that I sent you?I thought you used 'em all by now!

Literally just used the last SDC kit 10 min ago
Sp70 tunes up nicely now.

Will have a go at the oiler tomorrow. I'm pretty familiar with getting them sussed but I do have a box of stubborn ones that pump well with ya hand but don't work well in the saw. Some are also from the 850 that never wants to oil. I take a known pumper from a saw and nup 850 no go and always loses prime with the manual too. Frustrating

 

[Syncop8r]

The last setting I tried yesterday was 3/4, well it fired up today still set at that - perhaps it needed to dry out after initially being too rich?
There was a bit of smoke coming off the muffler whist pulling it over - unburnt fuel?

View attachment VID_20230703_142948034.mp4

Ugh I guess I need to tune it now...

 

[Jethro 2t sniffer]

The last setting I tried yesterday was 3/4, well it fired up today still set at that - perhaps it needed to dry out after initially being too rich?
There was a bit of smoke coming off the muffler whist pulling it over - unburnt fuel?

View attachment 1094381

Ugh I guess I need to tune it now...

Could of just been flooded