McCulloch Chain Saws

[edju1958]

Don't you just love it when you open someone else's old can of worms?I can't tell you how many times that has happened to me.It is really nice though when you get a saw that needs minimal work to be a runner.The unattached disc to the pin would explain the no oil issue,but what about the leak?Gasket?
Ed

 

[mogulmasher]

I think the manual pump was building so much pressure that it was just leaking at the gasket. I can't see any damage, but the area had fresh bar oil, so had to be coming from there. There is also no blockage anywhere.

I also can't figure out why manual oiler didn't just force oil past pump. Why does that disc matter for that to work?

 

[Maintenance supervisor]

I think the manual pump was building so much pressure that it was just leaking at the gasket. I can't see any damage, but the area had fresh bar oil, so had to be coming from there. There is also no blockage anywhere. View attachment 824837

I also can't figure out why manual oiler didn't just force oil past pump. Why does that disc matter for that to work?

Its probably feeding impulse pressure against the check valve would be my guess? As far as I know the disc is just a pump and shouldn't be full of oil or have cylinder pressure past it.
There are lots of posts about the oil pump and it's functioning and the strait manual pump.

 

[kbeck]

Been awhile since I done much with my saws but helped a friend clean up a big willow should have took some pictures but was to busy. I did see some picture taking so will see if they can send them to me. He lives next to a creek so the willow has always done well the base of tree had to be 4 feet or more with 1/2 dozen large spurs. Didn't take my pretty Mccullochs to brushy and wet more like swampy grabbed 3 saws a Olympyk 980, poulan 365 pro, and my pro Mac 700 all 3 ran great the Oly broke the recoil spring and was retired early I used the 700 the last hour only has a 20 inch bar but was buried most the time. Not sure if willow is a hardwood, softwood or combination of both but no match for the 700, being the first time cutting with saw I was impressed loud and powerful. There was another guy showed up with a husky 55 but only cut some tops. Still have to go back and finish job will be sure to get pictures. I did get a old blue Homlite XL12 for my troubles today Kevin

 

[heimannm]

The disc is the check valve to prevent the oil from simply going back down the pick up hose when the manual oiler button is pressed.

Mark

 

[mogulmasher]

Well did a little makeshift test. Dropped the pickup in a cup of oil and used a 3/16" rivet in manual pump rod hole. Within half a dozen pumps I had oil flow. Hopefully I'm outta the woods with this problem.

Maybe the disc in pump was jammed and backing things up? I have no idea. I also might have blow a blockage out of somewhere while cleaning and didn't even know it.

 

[MacAttack]

The disc is the check valve to prevent the oil from simply going back down the pick up hose when the manual oiler button is pressed.

Mark

Hi Mark, you wouldn't happen to know the factory tolerance resistance values for Mini Mac ignition coils would you? I have one with 7.38K on the secondary and 1.8ohms on the primary winding, and no spark.

 

[heimannm]

I have not checked a Mini Mac or Power Mac 6 coil but your numbers are right in line with the large frame and 10 Series coils I have tested. Around 1 Ohm for the primary and 6-10 K Ohm for the secondary. I don't think your coil is the issue. I would check the point again to make sure they are contacting consistently as the crankshaft rotates.

Mark

 

[MacAttack]

I have not checked a Mini Mac or Power Mac 6 coil but your numbers are right in line with the large frame and 10 Series coils I have tested. Around 1 Ohm for the primary and 6-10 K Ohm for the secondary. I don't think your coil is the issue. I would check the point again to make sure they are contacting consistently as the crankshaft rotates.

Mark

Thanks Mark! I will look at other potential issues. I'm a bit at a loss because I've tried the same coil in 2 saws and no spark with a power drill spinning it over. Maybe it's not spinning fast enough? But i have a Mini Mac 25 that had a good spark bench testing the same way. I will check the points, thanks again!

 

[2broke2ride]

Ok, oiler problems in the SP81.... here is what I found. On the manual oiler, we have an improper mix of parts. It has the thick flange oil pickup line used in conjunction with a thin gasket effectively trapping the check disc. I have options here, I have another manual pump with a thick gasket and I have a pickup line with the thin flange so one way or another I will get that sorted.
On the auto oiler, it had the plastic pump in it and it is missing the plug in the bottom.of the outlet channel. Can I just epoxy that hole shut? I also have an aluminum body pump but it is missing the spring and check ball unfortunately. Does anyone have a good used pump they would part with?
Thanks guys.

Sent from my SM-G950U using Tapatalk

 

[2broke2ride]

Where is everyone lol?

Sent from my SM-G950U using Tapatalk

 

[Goinwheelin]

Outside

 

[Todd Loosli]

Checking in, been working on the 73 . Trying to understand the fuel tank and system. I keep hearing about the diaphragm. Is that the copper piece on the bottom of the tank. If it is we are good. I don't want to take the tank apart, is there any reason I need to, it's like new inside of it.

 

[Maintenance supervisor]

Ok, oiler problems in the SP81.... here is what I found. On the manual oiler, we have an improper mix of parts. It has the thick flange oil pickup line used in conjunction with a thin gasket effectively trapping the check disc. I have options here, I have another manual pump with a thick gasket and I have a pickup line with the thin flange so one way or another I will get that sorted.
On the auto oiler, it had the plastic pump in it and it is missing the plug in the bottom.of the outlet channel. Can I just epoxy that hole shut? I also have an aluminum body pump but it is missing the spring and check ball unfortunately. Does anyone have a good used pump they would part with?
Thanks guys.

Sent from my SM-G950U using Tapatalk

I would reseal the plug in that pump.

 

[emf123]

Checking in, been working on the 73 . Trying to understand the fuel tank and system. I keep hearing about the diaphragm. Is that the copper piece on the bottom of the tank. If it is we are good. I don't want to take the tank apart, is there any reason I need to, it's like new inside of it.

That's the fuel pump diaphragm, it's probably fine. The bigger issue will be the diaphragm in the carburetor, have you had that apart? Leave the tank alone if it looks good, take pictures of how it all gets assembled - in case it takes longer than you think

 

[Todd Loosli]

Thanks for the help I appreciate it. The fuel pump had some crap in it but was easy to clean. I'll cut new gaskets and finish it and move on to the carburetor. Have found pictures are a must.

 

[PogoInTheWoods]

Where is everyone lol

Did you pull down the SP81 IPL I posted?

 

[Yotaismygame]

On the gray and black McCulloch bars who can tell me what font that is? Or does someone have a PDF of that logo?

Thanks

 

[ML12]

It has been a bit quiet in here. @2broke2ride here is some motivation to finish the sp81 you have:


4ft fir

 

[mogulmasher]

On the gray and black McCulloch bars who can tell me what font that is? Or does someone have a PDF of that logo?

Thanks

I don't know the font, but I think Sugar Creek Supply has stencils for the design your looking for.