Lee

I'm not overly familiar with these but are the crankcase seals good? If not then it will not draw fuel properly.

Agree with Stormin. Pull the flywheel and check that key. or Bad gas maybe?
 
I'll get some good pics of those engine pages for you this weekend, Sorry about that, it slipped my mind

From the O&R 20A manual;
Points gap is 0.015" to 0.018"
Coil to flywheel gap is 0.010"
Spark plug gap is 0.025"
 
The ESA 1973 parts manual gives the spark plug gap as 0.030"
 
David

I'm assuming this is a 20A engine. Here is a diagram of what I have. Let me know if you would like a better copy with a parts list and I can email one to you.
 
 

Installed the piston and rings into the blind bore.No easy task with out the proper ring compressor .Trying to figure out where everything goes and the order in which it must be put together has taken some time.Sure could use a parts diagram although I am getting there.not sure what the presets are for the carb but this would make it a lot easier . May be a while to I get back to it because of honey do lists!

One of the first things that I do before putting an O&R engine back together after dismantling for cleaning and rebuilding, is to give it a leak down test to see if the seals are good and other areas of possible leakage. First, I leave the carb off. Install the spark plug and tighten. Make sure that the points push rod is in place, preferably with a little o ring lube. I then stretch a balloon over the exhaust, past the rivet on the neck. I found a plastic braided hose, about 4" long, that fits snug in to the carb inlet. I then blow in to the hose until the balloon is pretty full, remove my mouth and put my thumb over the hose inlet. Good seals allow the balloon to deflate at a very slow rate. A decent sized leak can actually be heard, hissing out of the bad seal on the flywheel side or the pto side. Other leaks can be at the spark plug or the push rod o ring. I had one that had hairline cracks in the crankcase and took multiple times to find. It appeared to be an engine that had never been ran and was bad from the factory casting.

Courtesy of Webhead

Courtesy of Usedtoolman

Yes, the exhaust position puzzles me as well. The newer three blade is that hole in front of the prop. The older one has holes in the sides of the exhaust pipe.

The canoe, loaded. In choppy water twisting to mount a heavy outboard is delicate. Seldom have a portage/launch point that allows mounting the motor on dry land.

Oh! Thanks for the balloon test info.
Something else I found that I can warn about, is that when I removed the induction section to check the crankshaft seal,
I had to make a new gasket for the induction section. It was marginally thicker than the original.
Whether from the increased thickness, or lack of resilience of the old O-ring,
I needed to add TWO layers of the same gasket material between the o-ring and the induction hole, to seal around the
bolt.

Decided to get some parts together and rebuild this engine for a BeJay winch I recently bought.
The engine was covered in grime and very stiff to turn over. Since it needed to be completely disassembled just to clean it, might as well do a complete rebuild and document with some pics
Here's the winch
 

 
 
The engine completely disassembled and parts cleaned
 

 
 
Some of the NOS parts to be used. Cylinder, rings, connecting rod, complete seal/gasket kit, coil, flywheel, points, carb, ect.
 
 

The O&R part no. for the rings used on the Model 20A engine is 200023.
Don't forget to clean out the remains of the air filter, as they disintegrate just as well as the earlier engines.
 
David

Unfortunately I don't have much experience with those engines and only own one, which I have never taken apart. I'll search through my documentation to try and find a size but may only find a part #.
I would suggest you send a PM to member Webhead.(Joe Weber) He's not as active on here as he used to be but he might have the rings.You can also contact him through eBay as he has quite a few items up for sale now under Ohlsson Rice. His name on there is amcweb

Here is a advert from 1973 found online that has two O&R powered Lancaster chainsaws, the 20SLA Automatic that Lee has and the 15SLA Mini Automatic that I have.

 
Also attached are some pictures of my smaller Lancaster 15SLA Mini Automatic with the 13B engine. The air filter is different to the standard ones fitted to O&R's, also the instructions aren't quite right as the chain oiler is automatic.





 
David

Thanks I just ordered some rings from overseas .5 sets for $11.89 with free shipping.So I have little to lose if wrong size but I measured my piece of ring I found in engine for thickness and measured piston and bore so I think they will fit .May need to grind some to get wright end clearance .  I will post results once I get them and install. Thanks

Thanks I just ordered some rings from overseas .5 sets for $11.89 with free shipping.So I have little to lose if wrong size but I measured my piece of ring I found in engine for thickness and measured piston and bore so I think they will fit .May need to grind some to get wright end clearance .  I will post results once I get them and install. Thanks