McCulloch Chain Saws

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3 exhaust, 6 transfers and 3 smaller holes down low in the cylinder going to the port which bypasses the reed valve (third port)? Will be good to see pictures. The intake port is the wide opening below the cylinder and is controlled by the reed valves.
 
There was a PM55 on Feebay for $90,I bought it.Supposedly the engine won't turn over.I don't know if it's seized,or if there's an issue with the recoil.
There was also a used PM55 engine that was supposed to be "good".The seller was asking $100 or MO,I offered $70 & he accepted.
Looks like I've got a winter project ahead of me.
 
There was a PM55 on Feebay for $90,I bought it.Supposedly the engine won't turn over.I don't know if it's seized,or if there's an issue with the recoil.
My (probable)PM60 was supposedly seized, the starter recoil just needed fixing.
 
The seller sent me a message stating that he bumped up the shipping to Priority Mail & I should get the saw this week.When I asked him if he'd had the recoil off to see if that might be an issue.He responded saying that he "was too old to be working on his parts saws anymore".I have no idea how old he is,but I do understand.
 
I was fun running my rebuilt SP81 today with the LRB piston and the saw stopped so abruptly that I knew it was the ignition chip.
First time I've ever fried a NOVA2 on one of my saws.
I plan on running this saw as I'd like to see if it is gonna let go with the LBR piston , honestly I don't think it will because of the difficulty of pressing the bearings and pin in the rod. I had a very good fit, and its a bear to pull over with out the decomp.
 
I personally don't care for the Nova II chip,it's too thick & bulky.I use a slimmer one wire chip & have had good luck with them.I think they're made by Rotary.I think the best chips ever made were the Atom chips.I've come across a few saws with the Atom chip in them & I've got to believe they've had those Atom chips in them for at least 40 yrs.
 
Very interesting experiment there with your sp81. Ive lost one nova chip. It just quit the same one day. It was running then just stopped. Ive had no issues since. Inidentally it was my sp81 with a lrb piston also. Its been in that saw for many hours. My 1st rebuild.
 
Gunna need to try 1 of these chips 1 day. My 81 still has a bit of a sad spark to it. Runs OK but does have a clear "miss" to it when first started and will just cut if left to idle while it's cold.

Went away after cleaning up the points but sorta back again.

My victa 2 stroke lawn mowers of a certain vintage in the 80s early 90s ran a chip just like these. Actually often a victa with no spark is the chip. Later on they built them into the coil anyway bla bla I'm pickin I could probably use 1 on a saw

Orr... I tear apart the 850 and flog it's engine :) mint 850 but it won't oil to save its life and is heavy compared to the 81.

I actually rather run my ducted exhaust 800 over the 850. I'm convinced the 800 pulls a higher RPM. 850 fends off a stall slightly better but that 800 man that 800 howls

Maybe it's this great big hole
20191205_201316.jpg

The 850 oiler....

I've tried a new pump I had I know pumps. No change.

I've stuffed a ground down nut under the pump incase it was the seal. Nup

It oils at idle happily.

Open throttle it goes dry and when manually pumping it needs re primed.

Eg 3 or 4 pumps before pushing oil. 5 seconds later same thing.

Grrrr so parked it is awaiting something or nothing I dunno it's just parked. I use a Poulan or husky instead hopefully pissing it off enough to make it realise it's missing out

Hopefully also it reads this too
 
Have you run a piece of wire through the impulse hole to the crankcase? Maybe a little bit of sealer from assembly just blowing back and forth between them?
Just a thought.
Worth a shot. Good suggestion. Whatever is happening it looses prime in the manual pump really fast
 
Worth a shot. Good suggestion. Whatever is happening it looses prime in the manual pump really fast
I know there's different thickness Gaskets for the thimb pumps but I'm not sure how that affects the system?
Also the check valve sticking with make it inoperable.
 
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