McCulloch Chain Saws

[docholliday64]

Hey guys, I picked up a decent PM 850 recently and was wondering if anyone in the group has a handlebar (92707) that still has the padding on it (mine is pretty rough). Also looking for the frame brace grommet 93032. These are a few things I can see on the surface to get me started, I'm sure there will be more.....

 

[heimannm]

https://www.ebay.com/itm/1869001680...mmPcnfQQc/BneY3d8VwlHeSg==|tkp:Bk9SR5CbmaqeZQ

https://www.ebay.com/itm/1868903437...hplXpVKl3jrYxPUBazlLWqLQ==|tkp:Bk9SR5CbmaqeZQ

I have a few "aftermarket" options if you just want a functional piece and don't care if it is 100% original.



The full wrap bars are pretty pricey, even for used ones. If the only thing amiss with yours is the padding, consider stripping it off and using some cushion wrap tape from a bicycle handlebar or hockey stick.

Mark

 

[docholliday64]

https://www.ebay.com/itm/186900168004?_skw=mcculloch+93032&itmmeta=01JKSA69NXQM316KRKK57B8BA9&hash=item2b841e3d44:g:1MUAAOSwJZlnisYB&itmprp=enc:AQAKAAAA8FkggFvd1GGDu0w3yXCmi1fBHY6aFhZ4sv3YrUiw78eTf9QT/5nZeovqEd6USzncPciJWO0DNoRArI24OdPH+K1zabiP4+vtosDGJ4sOy2COxNMuZh/Esgd+GCXxwbFJhTXmH45WNrTm/Vtf8IGoDh8aKLEvDqO9qwHMlhyt+rhRfPd5CGLKThbZ11iGCDeO+m0QLhl4KJeOKlPjCTClFBgD1icpjRx3NfRb6k+r3ASgfuHwnJB0BwvLLvd0dmj6kq08NJX4gZ9wTh5EzW+F/NLTiaAf6B/s4K1a3BXmwdmmPcnfQQc/BneY3d8VwlHeSg==|tkp:Bk9SR5CbmaqeZQ

https://www.ebay.com/itm/186890343753?_skw=mcculloch+93032&itmmeta=01JKSA69NXXQ14RZRK7ZP3KPHY&hash=item2b83885549:g:vAsAAOSwhtRnhGxD&itmprp=enc:AQAKAAAA8FkggFvd1GGDu0w3yXCmi1e2SyrfcOeu6dfCk01/q5LaFZHQ3ZEfxp8BsHDmzh3NXRmGjp/SdrzizJgM0/vtSOVOvqIhZLDZReYTzVQjf8ZTeEHnWxg8CJfMKB6VJVQLFE40U0NjQNtDIDUcUHuLKQMjYH/clj9slpUyJLOW9pOT8OTPPURjvJdv8koxIK9CC2PV8x24E8clg5u+OPpAKXALX9s5ITsDyzn7Gydd0BKM7Abg+o54Gr1ttPqN6muyxWceio6pkUnENHdBtzoM8CZDYH0BkFUzGKvKofp1oVhplXpVKl3jrYxPUBazlLWqLQ==|tkp:Bk9SR5CbmaqeZQ

I have a few "aftermarket" options if you just want a functional piece and don't care if it is 100% original.

View attachment 1241243

The full wrap bars are pretty pricey, even for used ones. If the only thing amiss with yours is the padding, consider stripping it off and using some cushion wrap tape from a bicycle handlebar or hockey stick.

Mark

Thanks Mark - I like those grommets - I don't really care if they are original or not - just need the functionality.
Send me a PM - I'll get some of those from you.
As far as the bar goes, I have some EPDM tubing that I have used on other 10 series saws, a pain to get on (I use compressed air), but seems to work pretty well. I'll probably go that route with the 850.

 

[JSMississippi]

All my parts are in now! We are heading to the camp on Thursday, still a small chance I can get this S back together in time. If not, it’ll wait until next time. We shall see!

 

[Squareground3691]

Pick up a nice original Mac roller nose ,

 

[heimannm]

I went through another batch of flat back primers today. It is always a very messy job with the leftover goo from the cup seals.



For those that haven't seen the process, I start by drilling a small hole in the end so I can press the works out. I use the peck drill in the lathe for better feel when it goes through.



I made a simple tool to use in the arbor press for taking them apart. Since the body is 1/2" square I hold them in a 1/2" drive deep socket while pressing the innards out.



To seal the hole in the back end of the primer I tap the hole I drilled and install a small set screw.



Once the parts are cleaned up, I install a new cup seal and new o-rings. To get the parts pressed into the correct location (depth) I made a couple of tool to use with the arbor press.



I use a can with Seafoam to test them and make sure they actually pump; Seafoam is a bit oily and doesn't smell as strong as mixed fuel and is not too hard on your skin.



I also pressure test them to make sure they hold 10-15 PSI.



Mark

 

[docholliday64]

That's a pretty cool process Mark - thanks for the walk-through

 

[JSMississippi]

Well, we have a complete chainsaw again!


Finished it up this morning and at the camp now. May have time to crank it up tomorrow and start tuning!

Pressure tested once it was back together and could not track down a small leak. Not at the seals or the crankcase mating surfaces. Not at the fuel tank intake spacer, carb, muffler, or spark plug. Finally saw bubbles at the manual oil pump gasket and the oil tank gasket. I’m wondering if this if from the impulse channel that I think Mark mentioned earlier?

We’ll see if it gives me any air leak symptoms. I’m stoked to have it going!

 

[Rallyeguy]

Good lookin machine

 

[heimannm]

Just a few final comments...there are two different part numbers for the primers (53449 and 68702) and I assume this is 53449 that uses the 24104 cup seal on the aluminum plunger.



As shown above, there are two o-rings uses, one on either side of the gland. The outer one (between the gland and the retaining ring) prevents the primer from leaking back through the exposed plunger and the inner one seals the fuel at the inlet (between the gland and the plunger body) when the plunger is retracted by the spring.



What I assume to be the later part number (68702) uses a different cup seal (67116) and a steel plunger with a notch cut in the end. See the one in the middle below.



I think, because of the differences in the design of the plunger but more importantly the cup seal, the earlier primers with the aluminum plunger and 24104 cup seal deliver a lot more fuel with each stroke. As you may be able to tell from the photos, 24104 is also much more prone to degrading and turning to goo...



Mark

 

[JSMississippi]

No luck so far. It’s acting like it has a BIG air leak I think. Will run off a prime for a few seconds and tries to rev up proportional with how much fuel I squirt down the carb. Will not run on its own.

Busy working at the camp so haven’t had time to get back to it. I’m thinking back and I am very suspicious that the carb is not seated against its gasket/spacer. The gold colored half/rhombus brace thing that goes under the two bolts on either side of the intake bore (circled in the IPL screenshot) - I had four washers in the bag with it, put one under the gold part and one over it and put the bolts through (drawn in blue is how I have it currently). I’m thinking the bolts might be sitting too high because it looks like the carb is hitting them to my eye. Do I have this wrong? There is a thin gold colored washer and a thicker black washer.

 

[Rotax Steve]

Need a part for the SP81 E I'd told you guys about a week ago. The manual oiler was not working and Vinny's been helping me figure it out (thank you to him btw). After tearing it down and dismantling the oiler I believe the o-ring is weak but the bigger problem is the housing. There are two threaded holes at the end. The one on the right (in the video I'm attaching) is where a starter bolt goes. The one on the left is to hold a shroud. It looks like someone over tightened a starter screw and it went through into the oiler cylinder.
Not sure if it's repairable? There's a blob of metal inside the housing at the end of the cylinder. I don't know if it's from the housing itself or if it's a patch someone tried to make. I think a machinist could patch it but it's beyond me.
So I'm in search of a manual oiler for the SP81. Vinny also said the same one is used on the cp55, sp60, cp70,sp70, sp80, sp81 saws.
The housing is all I need (I think) which is part number 91218 or 69582 (but if anyone has one has the whole assembly I'd probably be interested in all of it.

 

[heimannm]

Those locking plates often get distorted when tightening the screw down and interfere with the spacer (Item 47) from setting down properly. The two washers with the smaller O.D. (thin gold?) go under the lock plate, there are not supposed to be washers on top of the lock plate. Those upper washers may be causing the issue.

I have also found on a very few saws that the boss the spacer sets on is not flat and have had to scrape or machine them to achieve a good seal.







There are two gaskets (59, 61) and an insulator (60) between the airbox and the cylinder. That is another area that is prone to leaking, or getting the gaskets and or insulator out of position producing a leak.



Mark

 

[heimannm]

Steve - I have the manual oiler bodies, O-rings, and plungers available.



Look Ma, no hole...



One or both of the screws that go in to these often get broken off or stripped out.



Mark

 

[JSMississippi]

I think that’s going to be my issue then. Those black washers are about twice as thick as the thin gold ones that are supposed to go under the lock plate.

When I pressure tested, I initially had a small leak at the tank insulator that resolved after tightening the bolts more, so I need to be mindful to get them snug without pulling aluminum threads.

My guess as to why I didn’t find the carb base leak when I pressure tested is the rubber I used is much thicker than the gaskets, giving the bottom of the carb enough clearance over the bolts.

 

[heimannm]

Also keep in mind that those screws are 12-24 not 10-24, it is quite possible to install the wrong screws and the 10's will very easily pull the threads out.

Mark

 

[Rotax Steve]

Steve - I have the manual oiler bodies, O-rings, and plungers available.

View attachment 1242612

Look Ma, no hole...

View attachment 1242613

One or both of the screws that go in to these often get broken off or stripped out.

View attachment 1242614

Mark

Mark, I thought I had sent you a PM but not sure if I did? So if this is a repeat you can disregard.
I can do PayPal or Venmo

Steve - I have the manual oiler bodies, O-rings, and plungers available.

View attachment 1242612

Look Ma, no hole...

View attachment 1242613

One or both of the screws that go in to these often get broken off or stripped out.

View attachment 1242614

Mark

Mark, I thought I had PM'd you but not sure I did. Please let me know what I need to do. I can pay with Venmo or PayPal.

 

[heimannm]

I have replied to your PM.

I have the pump body, plunger, O-ring, gasket, and the boot if you want them.

Mark

 

[Jethro 2t sniffer]

What have I done

 

[vinnywv]

Oh no jethro!!!! You sir have messed up. Lol

Although i bet once you get it sorted out right it will run well. Maybe