O&R Engine rebuild pics

[Wallfish 698]

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.

 

 

[Wallfish 698]

Started with the piston and connecting rod.

The new rod has a slot to let more oil into the bearings

 

 

 

New rod installed. Then did the rings

I use this motor assembly grease on everything which was recommended from Webhead

 

 

 

Then decided to replace the crank seal in the induction part. Had to pick the old one out with a small dental pick tool

 

 

 

 

 

 

[Wallfish 698]

Time to install the crank into the case

 

 

 

Crank installed into case, then bearing for connecting rod. then connecting rod with pistion

 

 

[Wallfish 698]

Next is the other half of the crank, reed valve and induction sector.

*Something I missed documenting is there is also a seal inside the reed valve part. Just past the bearing race. It's the same exact seal as the induction part seal

 

 

 

The thin paper gasket which goes onto the reed valve is difficult to get on without breaking it. I found that soaking it in the same fuel mix to run these engines softens it up enough to get it on.

 

 

 

 

Next is the induction sector with gasket was installed. Use screws to hold it in place.

This is a good time to install a new points push rod seal too.

 

 

 

 

 

[Wallfish 698]

Next I decided to do the back plate, points, outer bearing and crank seal.

 

Grease the points push rod and install the flat end through the seal and into the engine after the plate is installed.

Be sure to clean the points! Even if they are new from the package. Might as well gap them too.

 

 

Seal is tapped on over crank bearing using a socket. The groove side of the seal faces into the engine.

 

[Wallfish 698]

Now for the cylinder and exhaust manifold.

 

 

First install the gaskets and manifold onto the cylinder head. The rubber type gaskets are 2 different sizes. The one with the larger inside diameter hole goes on the cylinder first. Then manifold, then 2nd gasket, then metal rings, then O ring. Tightened it by hand and then I'll use a tool to get it tighter if needed. Turning the manifold with the cylinder at the same time will get it close to tight

 

 

 

[Wallfish 698]

Time for the coil and flywheel

 

 

 

Mount the coil but leave screws loose

 

 

Install flywheel and don't forget the little key and the points cover. Point the key towards the coil so the magnets don't attract to the coil during installation. Make sure it seats properly on the taper of the crank and tighten nut and washer onto crank. Then turn flywheel so the magnets are at the coil. I use a business card to gap the coil and the magnets will pull the coil tight onto the card so it can be locked into position easily with the screws.

 

 

I decided to use the original short wire condenser. If using the long wire type, you can feed the wire at the same time you are doing the coil wire so it can be mounted on the other side of the cylinder. The coil wire and condenser wire mount to the little post which connects to the points. This is where a shut off can be connected to as well.

 

 

Now is a good time to give the flywheel a whirl to check the spark. You can spin it by hand and should see a consistent blue spark.

 

[Wallfish 698]

Next is the clutch and gearbox. Pretty much self explanatory how to put these back together after you take them apart.

Cleaned the bearings in a jar with carb cleaner.

 

 

Used the motor assembly grease to fill the case and grease the bearings.

 

 

 

I find that these types of clutches with the cork linings tend to grab the drum prematurely. By sanding down the cork at these points, it does cure that issue BUT will probably shorten the life of the clutch. I don't use these engines for work anyway so I prefer to have them work correctly for the short periods of time that they do run.

 

 

All together

Forgot to take pics of the seal for the PTO shaft of the gearbox. It's the same as the induction seal earlier in this thread

 

[Wallfish 698]

That's about it for the engine and gearbox rebuild. Just need to add the air filter, muffler, governor vane and recoil. 

I did put a used carb on it for now until I run it for a test but will then swap that out for a NOS carb and leave it like that.

 

This engine does not have the thrust washers and the bearings sit in a plastic cage. Newer versions use the thrust washers and have steel cages for the bearings among other small differences so it's ALWAYS a good idea to have the correct drawing for the engine.

[Stormin 4,458]

Excellent instruction guide, John.

[tackdriver56 2]

Excellent resource! I'm working on a Polaris Power Pole (3/4 HP O&R), and suspect that the original shaft seals are the reason it won't stay running (carb diaphragm is stiff but intact). I'm NOT looking forward to major disassembly, but your photos will be a big help, if I work up the nerve...

[Wallfish 698]

A good flexible diaphragm is critical to get your engine to run properly. It can't pump enough fuel or keep it consistent enough if it's stiff so you should certainly start there.

I've had plenty of engines run OK without replacing seals BUT if you want the best performance, seal the case. No big deal to me since all of my engines are for display only but I do get all of them running. To me, they just seem like a pretty boat anchor if they don't run.

[tackdriver56 2]

You sell the replacement diaphragms? Do they include the metal disk adhered to the originals?

[tackdriver56 2]

Does anyone know the specifications or exact measurements for the crankshaft U-seals?

Also, any advice on how to safely remove the centrifugal clutch from the crankshaft, before I try a generic puller? (This is internal to the Polaris Power Pole gearbox, similar but not identical to your winch?)

Edited February 26, 2015 by tackdriver56

[Wallfish 698]

I have seals but no way to ACCURATELY measure them, other than a ruler. Webhead should be able to hook you up with new seals and gaskets.

 

You shouldn't need a puller to remove the clutch. Should be a bolt or screw which holds the center clutch part to the shaft. Some shafts are D shaped, some are tapered shaft. You'll need to look down inside the center, under the clutch springs. Think the blowers used the bolt with a 5/16 head. I can open one up and get pics if needed. The clutch pictured from the winch is an old style cork lined clutch, I believe yours should be steel with 2 flat springs spanning the center hole. Pretty sure this is a drawing of your gearbox.

[tackdriver56 2]

It looks good... I'm going to take it apart soon.

Thank you!

Edited February 27, 2015 by tackdriver56

[tackdriver56 2]

Question: Is there supposed to be a long screw/bolt from the large gear-case shell, crossing THRU both sides of the carburetor mount, threading into the side of the crankcase? It sure looks like those empty holes could be an air leak to the gear case.

[Wallfish 698]

Yes, there is also a small O ring seal that goes into a hole on the case to seal that connection of the parts together.

[tackdriver56 2]

Seems like somebody worked on this before, and had parts leftover At least the case o-ring was still in place. I guess the only reason it ran for me the first time, was the heavy oil I filled the gear case with ;-) At least the 8-32 x 1.25 screw & lock-washer should be easy to find.

I did get the induction side crank seal out. The shaft diameter is 0.36",and the seal OD is about 0.49". The seal cross section is approximately 1/16" square (u-shape).

Edited February 27, 2015 by tackdriver56

[tackdriver56 2]

Success! Aside from finding and installing a compatible screw to replace the one missing from the gear-case through the induction stage, I also cleaned debris found in the fuel passage from the diaphragm to the filter screen. Gear oil stays in the gear case, and the engine runs! The PPP cleared a lovely patch of snow today! Thanks Wallfish, for your helpful advice!

[Webhead 95]

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.

[tackdriver56 2]

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.

[hydrodriver 0]

Hi - I've got and O&R Model 123 Chainsaw, at least I think its a 123. It appears to be in good condition and complete.  I need the Bakelite points pushrod and a flywheel key - any idea where I might find these?  Thanks!  Bernie

[factory 487]

Welcome to the forum Bernie.

Send either Wallfish or Webhead on here a message, they both have spares for these engines, Webhead also has replacement diaphragms for the carb.

 

David

[Oldjimturbine 2]

I would like to know if there is any easy way to move the exhaust to install a fuel tank.  The exhaust and cylinder head won't budge.  Is there something I have to remove first?