Dan Vincent

OK Cub .099 engines went through several changes.

The original version from 1949 had the needle valve very close to the propeller and it was pretty near impossible to adjust without getting your finger buzzed.

The original 1949 engines had serial numbers on the bottom of the case but that stopped with the second run in 1950, same engine, no S/N.

Around 1951 they changed to a longer prop driver but it was still a close call.

Cubs were later offered with pull starters and tanks.

Around 1958 they modified the case and offered the "Squareback" version.

The .049 and .074 Cubs and the .14 and .19 were all built with a three screw radial mount as part of the case. Why the .09 wasn't done the same way has always been a mystery to me.

1) Original Cub .099
2) Extended prop driver model
3) Comparison of prop driver length
4) Late model "Squareback" .099-S (Starter)

Dan Vincent

OK Cubs could be radial mounted using this neat little 2-piece accessory mount.

This was made by Herkimer for their OK Cub .09, it is Part # 950.

Herkimer also made Cylinder Removal tools for all sizes of their Cub engines.

This is a Cub .14 tool that fits a McCoy .09 diesel perfectly.

jjscott

To resurrect this thread, I have a problem with a Cub 099. I bought what appeared to be a very nice Cub 099 off ebay. When it arrived it was dry of oil and had low compression. I removed the plug to put some oil on top of the cylinder. On tightening the plug the head just twisted free.

The head is too small for the cylinder. It drops straight down in into the cylinder without the necessity of screwing it in. For the last 1/32" and 1/8 turn it sort of tightens and holds itself in place. There does not appear to be damage or wear to either the head threads or threads in the cylinder. Could I have an 074 head in place of the correct one? Are they that close in size?

Here is the engine. The head doesn't look undersized, or is it? Picture loading is not working. I'll try loading tomorrow.

Any thoughts and ideas where I can come up with an 099 head?

Thanks, Jim

Dan Vincent

Sounds as if you might have an .074 head. No, I don't know of any source for replacement. Buy a junker .09 on ebay and steal the head.

Cubs were made in .024, .039. .049, .06, .074, .099, .14 & .19. Diesels in .049 & .075.

jjscott

Thanks Dan. I've pretty much concluded the engine has an 074 head. I've got a lead on another 099. We'll see.

Jim

Steve J.

My Feedback: (2)

Does an OK Cub .099 use a 5-40 prop screw?