Chain saws - Cox made them - and the "Silver Bullet"

page three

I won those two Cox chain saws, 2 bidders only, he bid me right up to and including my top bid.

Not much about these on the net, just what I posted above in Dannels Sitter. An adaptation of the Cox bicycle engine - 1.40 ci two cycle mixing 30 wt at 16/1, same as my other chainsaws. Less than ten pounds with a 12" blade one will make a good "limber" the other will be disected, cleaned, repainted............etc. etc. A good winters project.

I thought others here owned one, but I guess not. Sure would like to compare notes.

Rained last night, no woods work today.  All my work benches are clean so I started on the worst Cox chain saw.  Pull cord pulled half way out and would not retract.  Can't figure why, the ratchet mechanism works fine.  



So, I tried to rotate the flywheel and the chain drive.  Locked up solid.




Removed the spark plug and got a surprise.  Cylinder filled to the top with gasoline/oil mixture, standard 16/1.  Poured it out into a cup spilling some.




Somehow you know this is a Cox product.  Nicely cast COX into the engine, flywheel, and handle with a nice basket-weave effect.  Probably many parts farmed out.  




I have yet to remove the flywheel and pull/start mechanism.......sticky.  Eager to get to that engine.


Edit add:

Got the ratchet off. L shaped hex key would not do it. Took the cheap Walmart tool to do the job.




Leroy put his name on it



Flywheels always a problem. Jacobs area of expertise. Tried my puller and can't get the claws under it. Tried the age-old method of holding the flywheel up and hitting the shaft with a plastic faced hammer. No go, Penetrating oil knowing it isn't going to help.

Heat the flywheel with a heat gun, should do the trick.

Don

pman1111 wrote:Heat the flywheel with a heat gun, should do the trick.

                      Don

Thanks Don,  I was thinking my butane pencil torch, but a heat gun might be better - there is still gasoline floating around this thing.  

Coming apart.  Someone had been in there before me.  Loose/missing screws and I found this broken piece off the drive shaft housing. (In front of the tapping hammer)



Evidently he tried to get the housing off by prying at the most weakest point and snapped it off.  Must be a locator of some sort as it has four other bolts holding it on.  I don't think it's necessary, but it will go back on with a little JB Weld.

I put the pivot back on to protect the threads.  This time I'll smack it with a proper hammer after I heat it.



Leroy forgot to specify threaded holes in the flywheel for a puller.  No way to get a clawed puller under it.

My thinking was a heat gun might be less likely to ignite gas fumes, also the heat gun should heat a larger area of the flywheel. The broken piece is likely a dowel to lessen the shearing load on the bolts holding the housing the chain bar mounts to. I'm a little surprised the previous work didn't break a couple flywheel fins where they tried to hold the flywheel from turning with a screwdriver when they removed the flywheel nut. (seen that a lot)

Don

Yes, the previous owner or repair guy was not a veteran, so many apparent mistakes on this chain saw.

I was thinking, how did all that gas get into the cylinder, it was filled to the top. Perhaps the reason (hydraulic lock) why the flywheel would not turn. Not the case. But the better explanation is that he filled it with gas hoping to free the piston. The easy way out. It's a mechanical issue but that gas was not going to help.

There is a piston in there, and maybe a ring or two.

Reply from here: https://www.coxengineforum.com/t15139p25-here-we-go-again-another-lawn-boy#226645



The Lawn Boy manual suggests hitting the "thick" flywheel fin with a soft hammer while lifting the opposite side of the flywheel with your hand. I used a 2 jaw wheel puller to remove the flywheel on my Lawn Boy. It actually popped off while I was tightening the puller by hand, so it really wasn't on there that tight. May be an indicator that it could use a new flywheel key... I don't know. I did apply a little bit of vintage Liquid Wrench on the shaft a little while before pulling it the first time. I torqued it back down to the recommended 30 ft lbs.

You could try smacking it with a hammer a few times, being careful not to bust a fin off. Maybe put something like a large socket over the fin so the force hits the flywheel base rather than the fin. Another idea could be to make some hardwood wedges and hammer them in on opposite sides under the flywheel or with three in a triangle pattern, tapping each one in a little at a time.

Admin wrote:Another idea could be to make some hardwood wedges and hammer them in on opposite sides under the flywheel or with three in a triangle pattern, tapping each one in a little at a time.

Or not, the casting of the chainsaw body/case does look a bit thin. You be the judge. You may need to get a cheap set of harbor freight wheel pullers and grind the hooks down thin enough to wedge under the flywheel, hoping the hooks don't break off.

Thanks Jacob. I do have those HF pullers both 3" and 6" models. Long ago I did grind the claws, still pretty useless for tight fitting flywheels.

Going to give it another go today.

get in there with the red and black gas axe and show it whose boss.

Yabby wrote:get in there with the red and black gas axe and show it whose boss.

Heat and a big hammer got the job done. Used the torch consentrated around the shaft and a couple of whacks. Still, holding the flywheel up was no fun as heat travels.

excellent work Bob. its amazing how much muckin around is saved by the judicious application of heat and a big hammer

Yabby wrote:excellent work Bob. its amazing how much muckin around is saved by the judicious application of heat and a big hammer

Thanks Yabby, I'm having more fun than a kid with a new toy.  

Nobody picked up on the reeds? #52 on the parts list.





A rotary/reed valve engine? Seems Leroy never gave up on them.

Setting in this right now. Ron Cribbs told me about this stuff.

Hi All,
A ' person' got a job at a Canadian wood camp.
Chainsaw, cut down 10 trees per day.
Back at camp, Boss is furious, because he only cut one tree down.
Next day, he cut two down.
"You are fired", the Boss said.
To be fair, they checked out his chainsaw...
Chain was sharp.
Fired it up...
The 'person' said,
"What is that noise?"

Take care,
Have fun,
Dave

There is a punch line in there someplace Dave, I know there is, I know there is.................

Sandblasted the guide bar and the flywheel this morning. Cut a hardwood stick, heated the engine to smoking, hit the top of the piston with cooling penetrating oil and gave it a hardwood smack. Nothing! Tried again, still nothing. I don't want to crack that case. Engine puts out one whole HP.




Talked to these on my way in from the garage this morning. Three fawns and a couple of Mom's. They just ignore me anymore.

I'm not having any luck freeing this piston.

It's domed and when I hit the hardwood with a hammer while most of the energy is focused downward some of it forces the piston out to the sides of the cylinder, not good. I think I have to make a special larger dowel concaved out to the sides so all of the energy will be focused downward not out to the sides. Drive shaft to the chain is free to rotate after a good penetrating oil soak.



Trying a different approach. Apply the penetrating oil directly to the piston through the exhaust ports. I'll let it sit overnight, then tomorrow apply heat and try again. Fingers crossed. Unless someone has a better idea.

Making good progress Bob. That piston could be a tough one. I've seen people use ATF or Marvel Mystery Oil before to get stuck pistons unstuck in old cars and equipment. Pouring it in the top and letting it sit a few days to soak. Hopefully the rings aren't rusted too bad and can be saved.

Any signs it may have been straight gassed and seized?

can you get something in under the piston from below and try knocking it up a bit and then down a bit. the slightest movement up and down will help the penetrating oil etc. get in deeper. slowly bit by bit it might start to free up. same goes for trying to rotate the piston with the conrod. the slightest movement in any direction and then back again and backed by more penetrating fluid may very slowly free it up. i like kerosene, but thats just very light oil really, but has worked well for me.

hopefully the piston hasnt picked up cos if its done that badly you might have to sacrafice the piston to get it out. good luck

I think I have to make a special larger dowel concaved out to the sides so all of the energy will be focused

I wonder if you could line the cylinder above the piston with some very light plastic sheet to make a pocket of sorts….Fill it with epoxy to level the top of the piston to distribute the load more evenly…. Get your wood press to fit cylinder best possible….If your drill press is big enough, put some pressure on it that way….Would wax the cylinder good first to keep anything from sticking…. Just thinking out loud with you

 Thanks for the suggestions.

Jacob, it could be seized but I think it's just rusted. There is/was a lot of rust on the ferric surfaces but the evrorust removed most of it. The top of the piston just shows combustion residue. I can't get to it effectively from beneath Yabby, wish I could, and Robert I have thought of pressing it out/down and it may come to that.

However, the penetrating oil I put in the exhaust ports last night was gone this morning, a good sign. It must be going somewhere. Just put some more in.



Spent some of yesterday cleaning up parts.  PO had been cutting pitchy pine, insides were full of it.  Changed my mind about stripping and painting it.  Doesn't look too bad.  I wonder if Cox had the ladies assembling it.  Emblem says Santa Anna.