Shaeffer's Little York hit and miss engine

[gbritnell]

As I had posted in the finished projects forum the Shaeffer's Little York is finished.
The other day I got around to starting it. With a little bit of choking it fired right up but wouldn't keep running.
The fuel tank is at the rear with the top of the tank just a touch below the needle valve on the carb. The drawing called for a check valve in the line but Cole's didn't have a 5/32-48 MTP inline check valve so I thought I would try it without. I must have played with that thing for 2 hours and finally decided to make a check valve, which I did. After reassembling the fuel line I started over with almost the same results as the first time.
Next I thought I would hook up a remote tank near the carb and see what that would do. It helped alot but after about 2 minutes of running it quit. I choked it and it would restart only to quit after a few pops. I then realized the carb was as hot as the cylinder head and was pushing the fuel away from the carb, vapor lock.
I had my suspicions about the carb when I first started building the engine but assumed (and you know the meaning of ASSUME) it must work otherwise the designer would have changed it.
Other than a compete redesign of the carb setup to add an insulator block I don't see this problem going away.
One fellow responded to my finished project posting and said he had built one of these engines so I sent him a personal note for information. If anyone else is familiar with this engine I would appreciated your input.
Thanks,
George

 

[Catminer]

George
I am not sure if this helps but this is what has worked for my small hit and miss engines. I have found if I make the body of carb/atomiser a little longer and slightly larger OD, and add a series of fine cooling fins I have overcome the heating problem. I run them for quite long periods with little trouble from fuel . Also I have never used a check valve only small diameter fuel line,I bring the fuel line out the top of the tank to allow it to siphon down to the carb. And I have found that perfect intake valve seating is required as the slightest leak pushes the fuel back past the needle. By the way I was at your table at Names, you allowed me to fondle "the transmission", thanks for that.

Peter