Pro Mac 850 Question

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McLuver
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Pro Mac 850 Question

Post by McLuver » Oct 9th, '08, 20:15

Good Day,

I was the lucky bidder on a nice Pro Mac 850 a couple of months ago on the online auction. It's certainly overkill for the pecker poles around here. It came with a almost new 36 inch sprocket nose bar and chain as well as a new 20 inch chain with a used bar. This saw appears to have had very little use. When I got it, I put some mix in the tank, it fired right up and idled nice. It ran OK at low speed but sputtered when I opened her up. The compression is phenomenal. You can not pull the cord without releasing the compression. I cleaned her up, greased the clutch bearing, gave her a new plug and put her away.

I want to get her out in the woods this fall to scare a few people. I put in a carb kit - but still she bogs and misses when I open her up. I suspect an ignition problem. It's the electronic 850 version. I put a coil in her from and old Pro Mac 10-10 parts saw I have. She now wails like a banshee when I started her up for a few seconds.

So the question is: The 10-10 coil is a one piece unit. The ignition in the 850 is a 2 piece unit - a similar coil that mounts near the flywheel and a secondary unit that has the high tension lead mounted lower in the saw. Can anybody tell me if I'm OK with the 10-10 unit on the 850?

Cheers

PS - I'll try to up load some pictures when I figure out how.
It looks like I uploaded successfully!
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A user with a Poulan, a Husky and a Stihl .
Then there's also a McCulloch for every day of the week and a Pro Mac 850 for disturbing the peace on Sundays!

leeha
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Re: Pro Mac 850 Question

Post by leeha » Oct 10th, '08, 01:10

Very nice saw you bought.
Although i can't help you with
your question about the ignition
but there are a few members here
that i'm sure can.

I have 2 of these saws and enjoy giving
them a work out now and then.

Good luck with it.


Regards Lee

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Al Smith
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Re: Pro Mac 850 Question

Post by Al Smith » Oct 10th, '08, 05:45

As long as it runs it souldn't make any difference .

I just looked up the IPL on that thing .I always assumed they just used a 10 series coil arraingement but they are in fact some type of a hybred two piece deal .

The forerunner of that saw -sp 81 just used a 10 series points type coil as did the sp 125 .

Yes indeed those have a tremendous amount of compression .If that thing closes the decomp as you are pulling it over it tries to pull you through the starter sheeve and nearly does so .

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mcbob
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Re: Pro Mac 850 Question

Post by mcbob » Oct 10th, '08, 09:51

If your PM850 has the two piece black Phelon unit then i'm surprised in that it runs with the 10-10 ignition coil unless the 10-10 you got it out of has electonic ignition then these may fit straight in ..........

As regards the spluttering as you accelerate then try richening both the low and high speed needle and don't forget that these saws run a mixture of 32-1 ..............

Mc Bob.
Truely a man of many colours "Mc Bob", "Atomic Bob", Mc "Bender" Bob, Mc "Whiz" Bob, "Herr" Bob and "Whatever" Bob.

Thats why you should own a Mac first.
McBob .. 1949 and still kicking.

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Al Smith
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Re: Pro Mac 850 Question

Post by Al Smith » Oct 10th, '08, 15:47

If you tinker with Macs long enough you will come to the realzation a lot of us have learned ,many parts interchange .

The designs really didn't change that much except certain little things which don't make that much difference in the overall scheme of things . Just because the parts numbers don't exactly match does not mean the parts won't work for retrofit .

I've got a few 10-10s' for example which have both points type ignition and electronic moduals .The crankshafts for the points type will work on the electronic models but not visa versa because of no "cam " notch to activate the points .

That was just one little example ,there are many .Too many to remember ,at least for me .

That mouthfull said ,the 82 ccs Macs are real nice cutters ,lots of power and relatively light in weight . I think the 850 might have been about the last of the larger pro models that big Mac ever sold before they circled the drain .

McLuver
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Re: Pro Mac 850 Question

Post by McLuver » Oct 11th, '08, 23:57

Good Day,

I got the 850 up and running and cut up some big spruce today. Yes Lee it is a fun saw! Lots of raw power, great sound and great blue clouds of 32:1 smoke. After a little high speed mixture tinkering she went through 30 inch spruce with the big bar like a hot knife in butter. God I love the smell of 2 stroke smoke and fresh cut wood! I'll post some action pictures in a while.

I completely removed the two piece Phelon unit and installed the 10-10 coil. Yes McBob, the coil is indeed from a 10-10 electronic ignition donor saw.

Thanks also for the heads up on the 32:1 mix McBob. I would have just used 40:1 but when I read the fine print in the manual it says "Because the PM 850 is a very high performance engine, the normal fuel-oil ratio of 40:1 should be decreased slightly to a fuel-oil ratio of 32:1".

Indeed Al it is a very nice saw - even by today's standards.I've also got a couple of strong running PM 700's, but the 850 is in a completely different league! The anti vibe works quite well and there is little difference in weight compared to other 10 series Macs.
McLuver
Last edited by McLuver on Oct 13th, '08, 16:42, edited 1 time in total.
A user with a Poulan, a Husky and a Stihl .
Then there's also a McCulloch for every day of the week and a Pro Mac 850 for disturbing the peace on Sundays!

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Al Smith
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Re: Pro Mac 850 Question

Post by Al Smith » Oct 12th, '08, 00:46

Well,without splitting hairs or suggesting what saw is best ,big Mac had a leg up years ago .

The 10 series of what your saw is patterned after was light years ahead of it's time as far as design .Had the McCulloch board of directers not had their heads in the sand when Bob Mc Culloch lost his ,history would be different than how it turned out .

That series ,still today is likely the best designed engine ever made .

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RandyMac
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Re: Pro Mac 850 Question

Post by RandyMac » Oct 12th, '08, 16:36

I loved the one I had, always thought of it as a 10-10 on steroids.
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Al Smith
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Re: Pro Mac 850 Question

Post by Al Smith » Oct 12th, '08, 21:52

RandyMac wrote:I loved the one I had, always thought of it as a 10-10 on steroids.
Well in a way it actually is .

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RandyMac
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Re: Pro Mac 850 Question

Post by RandyMac » Oct 13th, '08, 04:53

Image
RandyMac pirate

McLuver
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Re: Pro Mac 850 Question

Post by McLuver » Oct 13th, '08, 16:47

RandyMac,
Those are great pictures - they should have been advertisements fo McCulloch in the 70's!
McLuver
A user with a Poulan, a Husky and a Stihl .
Then there's also a McCulloch for every day of the week and a Pro Mac 850 for disturbing the peace on Sundays!

tom benn
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Re: Pro Mac 850 Question

Post by tom benn » Jan 25th, '09, 11:58

you say that the coil is a two piece item, yes that is correct for the very early models when mcculloch first went to electronic ignition. as far as i know, the pm850 did not have the two piece system. an electronic coil from any other pm series saw should do the job so long as the carby is in top condition and tuned correctly. apart from that i suspect that there may be something wrong between the carby and the intake port.

seang64
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Re: Pro Mac 850 Question

Post by seang64 » Jun 23rd, '17, 16:21

I have a Pro Mac 850 . It ran great for me for five years . Then it stopped running . I has little compression and now I think it need a piston ring . Does anyone Know where I can order NOS rings ? Online etc. I live in Prince George Canada . I really miss not having this saw running .

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pete
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Re: Pro Mac 850 Question

Post by pete » Jun 24th, '17, 02:41

Did the compression issue happen quickly two suggestions make sure something has not jammed the decompressor valve open then as I found with two of these Remove the muffler and it is a bit of a long winded process as you need to remove the av handle assembly to get at it and possibly what you will find in the exhaust port will be a carbon build up that has worn the rings and possibly side of the piston. If thats the case I would try new rings which should be found on a popular online auction siten New OEM often appear there OMG may chime in as I cant think of the guys business something Marine parts but there is another word before marine
AS LONG AS I DONT SEE MY NAME IN THE OBITUARIES IM HAPPY,AND IF A MAN IS BUSY HE DOESN"T HAVE TIME TO DIE

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