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McCullouch 7-10 Automatic OVERoiling

idoseadoo

idoseadoo

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Hello, I was recently gifted a old McCullouch 7-10 chainsaw. The thing is a testament to old school durability. It started up with just some fresh gas. I filled it with good 40:1 fresh pre-mix and new bar oil and it ran great. However, I quickly realized that the oiler system did not work. Neither the manual, nor automatic. So I tore it all apart and finally found that the automatic oiler piston was stuck. I cleaned it all up and got it free. So then it worked. I started cutting my huge tree apart but quickly realized that the dang thing was OVER oiling. I popped the front oil cover off and adjusted that nut in many turns. It was almost touching the bottom of the oil reservoir, now it's much further up, limiting the travel of that piston. But I'm still producing huge gobs of oily spooge that start running over the bar cover. I wasn't using the manual oiler when it did this. Is there some sort of phenomenon I'm not aware of, like a blocked vent or something causing this?
 
Jethro 2t sniffer

Jethro 2t sniffer

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Awesome saw man you will have to peel my dead hands off my 7-10s lol.

Pop the lid again and give a few more turns should get it.

C'mon where's the picture's eh?

Come over and show us your pretty saw on the Mac thread it's like a bunch of weirdos perving at your lady oops I mean saw:) but seriously though that's where the yellow AA members live that you just joined:)

You'll be looking for more in no time 20190616_135409.jpg
Mac 7-10... perfection
 
homemade

homemade

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And some saws just pump like the Exon valdies. I have a mini Mac 30 like that. I’m not sure on the saw but some of the older saws ran off the crank not the clutch. So they pump oil whether the chain is spinning or not.
 
vizette

vizette

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Would look to Mark for verification on this statement: a lot (all?) of the 10 series pumps are driven off crankcase pressure/pulses. Common Mac thing, the mini-macs are like that too.

The adjustment screw you're describing should limit it, by limiting the pump travel... Not fluent enough in the pump design to offer anything useful beyond that, but I'm sure we'll hear something soon enough. :D
 

svk

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Does it excessively oil all the time or only when you have the saw on it's side?
 
idoseadoo

idoseadoo

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I don't think I ever had the saw tilted, I was cutting a horizontal log. It is definitely driven off the crankcase. @vizette thanks for that thread! I think I do have the sleeve, though I'm not sure why it's called that. Can't imagine not having it, as that's what the adjuster bolt threads into. Anyway, I recall all the parts in the diagram. One thing I noted is I may have the ball and spring out of order on the lower part.I'll yank it again and make sure. Very helpful thread though. Thanks for all the input fellas!

Got another off-topic question. I noticed the chain tends to slacken to the point of drooping. I'll tighten it, and a short while later, it'll be drooping again. Is there something I should replace? What is the best chain for this baby? Thank!!
 
homemade

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Tighten your nuts on the bar a bit. After getting to proper tension roll the chain around by hand a few laps the check again. Some guys lift the bar tip and adjust from there but I don’t. The chain will get balls tight if it slips when up cutting.
 
Brent Adams

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I was taught to always lift the bar tip before tightening the bar nuts. This puts the bar in the most normal position. If bucking or felling. Most pressure will be on the bar going upward toward the top of the handle. May flex somewhat during undercuts while bucking or during tree removal, but a solid bar mount plate like the Macs have usually negated this. Haven't had a problem with any of mine.
As to the excessive oil problem, maybe go back through the system after you have worked on it. 99% of my problems stem from something I have overlooked. We have been taught that we will be ridiculed for mistakes, but also be ridiculed for taking too long to accomplish a given task. This saw belongs to you. It doesnt matter how long it takes you to get it working properly.
Go back through the oiler system. Use the IPLs.
My 700 and 1010S were a little stingy with bar oil when I got them. I think this was a factory thing. All I needed to do on either of them was a turn out on the stroke limiter bolt, but they hadnt sat in adverse conditions for long periods of time either.
These are very good, very under appreciated saws for firewood cutting or general farm/homeowner use. They are EXTREMELY durable. They will last until the end of days with some basic maintenance.
I can understand a new lightweight, anti vibe, autotune, plastic saw if you make a living with it. If you cut wood to heat your home or to keep up a farm/homestead, these old saws are dead reliable and not too dependant on dealer only parts.
Most things you need can be found at any small engine shop, hardware store, auto parts store, or online. I think the only parts ive bought online for any of my Macs have been air filters and a coil once.
 
rwoods

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... Got another off-topic question. I noticed the chain tends to slacken to the point of drooping. I'll tighten it said:
With as much oil as you described your issue could just be really slick bar protector plates, bar and pitch points. You can’t tighten the bar enough to squeeze out excess oil. Just remove and clean the plates, bar sides and the pinch points of the clutch cover and tank. Should fix your problem if chain and bar are properly tightened.

Ron
 
vizette

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I was taught to always lift the bar tip before tightening the bar nuts. This puts the bar in the most normal position. If bucking or felling. Most pressure will be on the bar going upward toward the top of the handle. May flex somewhat during undercuts while bucking or during tree removal, but a solid bar mount plate like the Macs have usually negated this. Haven't had a problem with any of mine.
Agreed - when I tension, I hold the saw by the handle with the weight of the saw on the nose (resting on a log or workbench or whatever). Otherwise it'll loosen up the first cut. Then get it just enough that the chain touches the bottom middle of the bar, but not banjo string tight. Still slides around by hand with minimal effort. Don't think I've come across one that continually loosens though - interested to know if it is just the excess oil as Ron said.
Keep us posted if you get everything sorted out! I'd like to know in case I come across this issue in the future. Glad the oiler thread helped.

-Rich
 
idoseadoo

idoseadoo

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Update and possible resolution: I think I may know why it was overoiling. I spoke on the phone with a very knowlegeable chainsaw tech from Oregon about my oiling issue a while back. He said it's possible the system is just dry and needs oil forced into the pump to start working again. Said to somehow pressurize the oil cavity with 3 psi and that might fix my issue. Well, I drilled a hole and added a tiny barbed fitting from a carburetor that I had. The pressurizing trick didn't do it for me, as my pump was actually dirty with debris and pretty stuck. Only after a through cleaning did it start to work again. I left that barb blocked off with a piece of plugged fuel line. Well, as I was sawing, the fuel line got severed and essentially acted as a vent to the oil chamber. Yesterday, I put an actual plug in there and when I ran the saw, I couldn't tell the oiler was working at all. I could see the chain getting a bit of oil when working the manual oiler, but nothing from the automatic. So I think I need to go back and readjust that stop-screw, as I was seeing sparks and smoke off my bar. I think it was overheating. I didn't use it long like that, just a min or so. But I bet that vent was the reason it was over-oiling. It must require that area to be sealed properly to work correctly.
 
Jethro 2t sniffer

Jethro 2t sniffer

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It needs to breathe to be able to empty the tank. You said it was over oiling the pump is adjustable by winding the screw at the bottom of the pump in or out in for less out for more
 
Jethro 2t sniffer

Jethro 2t sniffer

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I re read your 1st post and you said you tried the screw. There is a thread getting around for the 10 series oiler by Heimanm maybe go have a read up. Cos I'm stumped and would just put in a different pump of a parts saw lol
 
idoseadoo

idoseadoo

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When I first tried the screw, it didn't do anything because the pump itself was dirty and seized up. After I removed and cleaned it, I had already added that vent. Recently I took out back apart to verify that I put it together correctly, adjusted the screw again and sealed up that vent, and now it's not oiling enough. I think I just need to readjust the screw one more time as the oiler is free. You can tell because the manual one works.

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