Unearthed old Mighty Mite - Entering Rehab

[RRRocketMan]

My dad dug up an old chainsaw (34cc remington mighty mite automatic) that was derelict for some time but he said the last time he tried to use it, it worked. We couldn't get it to run though. So I said leave it with me.

Couple weeks later I found someone to look at it who said the points were corroded so he serviced those, tuned the carb slightly and it works now. However it's in pretty poor health, all things considered.

There's an oil leak from the bar oil reservoir into the cylinder that not only fouls the plug quickly but also makes starting a do or die exercise. After too many attempts I have to pull the plug and flush the cylinder. Also the carb needs new gaskets although the old ones function for now. So I immediately ordered a carb kit (RK-14HU) which is coming and a new plug. In the meantime I ran it a few times and tried to adjust the screws to dial in the power. Pretty good results but damn the thing spews goop and smoke everywhere like it's coughing up cancer. Doesn't run for more than about 10 minutes at a time either, probably because the piston expands and too much goop.

So basically I'm looking for a broad range of advice here. I know fixing the leak (duck bill valve problem) is a good start and coupled with the plug and diaphagms that's not a bad improvement either. But what other things can I do to improve power, modify, enhance, etc this chainsaw? Any little tricks or freebies that are fairly straight forward to do? Any little thing would help. I really want to bring this thing back to life and get as much power out of it as I can. I also fixed a P20 but gave that to my dad. It was 50cc and as I understand it, more than 50% stronger, even though the displacement is 50% bigger. So I have a bit of a deficit to make up on the Mighty Mite. Any help appreciated!

 

[RRRocketMan]

Bump?

 

[pioneerguy600]

I have posted about them before on here , my Dad got one for Christmas from my mom the year he retired from his full time job. That little saw cut trees that most would not even consider dropping with less than a 60cc saw but my Dad was so skilled at woods work he could make it look simple. Trees around 24 - 30" made up the majority of what he cut with that little saw. I still have it and was given several more for parts, as soon as the duck bill dissolves and the engine sucks in chain oil most get dumped as no shop will touch them. They are what they are, they did cut wood but most are no longer working.

 

[RRRocketMan]

It's not an easy repair... from what I can tell it is rather involved, but it does seem possible. This video demonstrates the step-by-step procedure for replacing the valve:

It might be something I do later but for now I was just hoping there might be some bandaid style tricks for coaxing a bit more out of the saw.

 

[RRRocketMan]

And... I just attempted to fix the recoil and after 2 hours of trying to put the spring back on, all I managed to do is slice up my arm. So now I need a new recoil assembly to boot.

 

[pioneerguy600]

Someone must still like these saws for some reason, I have sent 7 different complete ones to upper Canada/Quebec. I kept 3, two are for parts but still complete. Some day I have to pull my dads saw apart and replace that duck bill, they all seem to need that done when I get them.

 

[RRRocketMan]

I figured, in the meantime, since the oil is leaking into the cylinder, I would lean out my gas mix to maybe 50:1 because surely it's getting enough lubrication from the leak. Perhaps I can even live with it like that. What do you think? The first 2-stroke that doesn't need pre-mixed oil and gas?

 

[pioneerguy600]

Bar oil is a poor burning lubricant, may have to fill the bar oil tank with two stroke oil.

 

[Captain Bruce]

I have posted about them before on here , my Dad got one for Christmas from my mom the year he retired from his full time job. That little saw cut trees that most would not even consider dropping with less than a 60cc saw but my Dad was so skilled at woods work he could make it look simple. Trees around 24 - 30" made up the majority of what he cut with that little saw. I still have it and was given several more for parts, as soon as the duck bill dissolves and the engine sucks in chain oil most get dumped as no shop will touch them. They are what they are, they did cut wood but most are no longer working.

referred to as dixie cup chainsaws.

 

[Patrick1903]

There's an oil leak from the bar oil reservoir into the cylinder that not only fouls the plug quickly but also makes starting a do or die exercise.

How can that happen? How does the bar oil get into the cylinder?

 

[cookies]

run 2 stroke oil as bar lube hardy har, all in all that does not look like a hard job that just requires patience.

 

[RRRocketMan]

Patrick: There is a passage way in the cylinder which, during normal operation, allows a pulse of high pressure to pass OUT of the cylinder and forces oil through the chainsaw somewhere. It's part of the automatic oiling system. It has a 1-way valve to prevent oil going the wrong way. However the valve is just rubber or something and it eventually decomposes into nothing so oil can leak back in.

Running 2-stroke oil in the bar reservoir sound like a pretty good idea actually. It might be prudent to blend it with bar oil though because otherwise it would have no "tack" and would fly off the chain. It probably lacks the viscosity to lubricate the chain and sproket properly. But with the right blend it might be just good enough to lubricate the cylinder and also good enough for the chain and I don't need to fix the leak!

 

[KASH]

It is plenty tacky
Mighty Mite worlds first oil injected power saw.
Kash

 

[RRRocketMan]

If I put acetone in the fuel, is it just the small rubber hose from the tank to the carb that might get eaten or are there other more permanent plastic parts I need to worry about? 12% acetone leans out the mix and adds considerable torque.

 

[cookies]

like the carb diaphragms, fuel tank check valves, crank seals ?

 

[RRRocketMan]

Aye... forgot about that stuff. Ok maybe I'll give the dog wet food on his birthday only then. 1 tank of gas shouldn't hurt it. Trying to think of other ways to wake this thing up.

 

[Brufab]

Might be one of those duckbill valves or whatever, surprisingly there's a ton of parts on ebay for them more so than any other model remington. Possibly run cheap synthetic mix oil for bar lube? Maybe instead of 16-50:1 run 1 part gas to 16 parts oil?

 

[TuckerSailor]

I took the side off the oil tank on my mity mite and replaced the duck bill with a pipe plug. Now I use the manual oiler . Works great . Now to find a crossover bar.