new Vintage McCulloch engine

[Lee Arnold]

First of all -thanks for letting me join!
I am 64 years old so the stuff on this forum is what I only could dream of in the late sixties and early seventies. I had a homemade kart that needed more power or a jackshaft-or both!

I'm hoping somebody can either help me or send me in the right direction.
My neighbors husband passed a couple years ago -he was a severe hoarder -and he was known for starting projects. One project was an ultralight helicopter -w found the basket and rotors pretty fast. A few months ago, after major progress had been made in the clean- up I came across what I assumed was a McCulloch kart engine that John was going to use for his ultralight -so I let the kid down the road take it- until I figured out what it was. It's never been used -looks like just a factory start up from the spark plug. No carbon anywhere -and it has NEVER been apart. If this valuable I would like to get a fair price for his wife -if not it goes on my mantle. I figure somebody may collect, or perhaps the karters used them after the kart engines were no longer made. Or perhaps somebody knows somebody who is into vintage ultralights. Personally, I would totally disassemble it prior to using it -one black spot on a bearing race or ball or journal leads to spalling really quick!

Here are some pics -it is spotless inside and out.

And a technical question -I have the carb apart. There was a black piece of crud that I assumed was sponge rubber 50 years ago -I see that it is a capillary plug. What do you guys to replace it. Not sure what it does since it is between intake manifold vacuum and crankcase pressure.

Thanks again for letting me join -if you want to boot me because I am past my kart years, I understand!
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[Jim Donovan]

First of all -thanks for letting me join!
I am 64 years old so the stuff on this forum is what I only could dream of in the late sixties and early seventies. I had a homemade kart that needed more power or a jackshaft-or both!

I'm hoping somebody can either help me or send me in the right direction.
My neighbors husband passed a couple years ago -he was a severe hoarder -and he was known for starting projects. One project was an ultralight helicopter -w found the basket and rotors pretty fast. A few months ago, after major progress had been made in the clean- up I came across what I assumed was a McCulloch kart engine that John was going to use for his ultralight -so I let the kid down the road take it- until I figured out what it was. It's never been used -looks like just a factory start up from the spark plug. No carbon anywhere -and it has NEVER been apart. If this valuable I would like to get a fair price for his wife -if not it goes on my mantle. I figure somebody may collect, or perhaps the karters used them after the kart engines were no longer made. Or perhaps somebody knows somebody who is into vintage ultralights. Personally, I would totally disassemble it prior to using it -one black spot on a bearing race or ball or journal leads to spalling really quick!

Here are some pics -it is spotless inside and out.

And a technical question -I have the carb apart. There was a black piece of crud that I assumed was sponge rubber 50 years ago -I see that it is a capillary plug. What do you guys to replace it. Not sure what it does since it is between intake manifold vacuum and crankcase pressure.

Thanks again for letting me join -if you want to boot me because I am past my kart years, I understand!

---

Most likely it is NOT a kart engine because for the application he bought it for it has a 3/4" crankshaft.  Kart engines had a taper crank.  Because of the 3/4" crank it is difficult to get the right gearing needed for a kart but that isn't to say the engine has no value.  An engine builder can eaily replace the crank IF he can find the taper crank to put in it.  What is it worth?  At least $600 to $800 dollars as is but with a taper crank then it is worth at least $1,000 if it is what you describe -brand new never been used.

[Mark Loraine]

The black goo in the carburetor used to be the duckbill check valve for the WalBro/McCulloch BDC Carburetors.

Some had luck using the Tillotson Carburetor check valve by bushing it in the cavity with a thin nylon/plastic shim.
Done right and installed the correct direction will last way longer than the original and is Alcohol friendly.
Seen here.
https://www.ebay.com/itm/374020366081?ha...R8Drw4q1YQ

[Terry Bentley]

Thats a Mc101 M/C. The same ones Horstman sold with the correct crankshaft to replace for cheap in the last years of McCullochs. Not saying it isnt worth a lot. Surprisingly there are a many of those still floating around that have never been run yet.

[Lee Arnold]

Thanks for the input, folks!

[steveohara]

Thanks for the input, folks!

Lee,

That engine looks to be in excellent condition and it is worth a lot of money. Even with the 3/4 crank, you could expect to get $1,200 to 1,500 for it if listed on ebay.
Mark was correct about the duckbill valve.... when they sit for many years they turn to goo. No need to modify the carb as there are several sources that you can go to to find the new valve. I highly recommend that you not start the engine without pulling it apart to inspect the bearings in the piston and connecting rod. It is very common for those bearings to freeze up after sitting a long time and if you run the engine with them frozen up the engine can be damaged severely.
If you intend to use it then I suggest you have it serviced before trying to fire it up.
Steve O'Hara

[David Luciani]

nice motor. worth around 500-1000 on ebay anytime.
at first i thought unused. 
but then noticed touch up repairs and some repainting.
so don't list as n.o.s. as it has some repaint work on it.

those motors were popular early on with ultralite people. 
seen alot of them come up for sale over the years.
d

[Lee Arnold]

Thanks for the input, folks!

Lee,

That engine looks to be in excellent condition and it is worth a lot of money. Even with the 3/4 crank, you could expect to get $1,200 to 1,500 for it if listed on ebay.
Mark was correct about the duckbill valve.... when they sit for many years they turn to goo. No need to modify the carb as there are several sources that you can go to to find the new valve. I highly recommend that you not start the engine without pulling it apart to inspect the bearings in the piston and connecting rod. It is very common for those bearings to freeze up after sitting a long time and if you run the engine with them frozen up the engine can be damaged severely.
If you intend to use it then I suggest you have it serviced before trying to fire it up.
Steve O'Hara

I've found duck bill valves for chainsaw oilers but no dimensions -Suggestions? It spins perfectly smooth so I would not be afraid to do a "just make sure it starts" test. I have decades of outboard experience, so I know a thing or two about resurrecting vintage 2 strokes! -I agree about total teardown & inspect prior to putting it in service

[Mark Loraine]

the red check valves for homelite are too small, if that's what you are referring to.

You can buy the proper ones from Elder Rubber in TX. Minimum purchase I think is 10.

Someone wanna leave a link here for him to get directly to the site?

[Terry Bentley]

Elder Rubber

That rubber duckbill is a check valve used in master cylinders.