TOPIC: 5 Cylinder 4 stroke outboard

Yes you read that right, these are pics I misplaced of a 5 cylinder Riley 75hp outboard.
I think at the time these were built they were the horsepower kings. If I recall correctly they were built in 54/55/56. This one is a 1956.
It runs.

Anyway, thought you guys would like to see another rarity in outboarding, a Riley 5 cylinder radial four stroke motor.

As I understan Rr Raily was way before his time on thse motors and just could not get the backing he needed.
Just like the Bear cats the motor came out of the Crosly car and back in 1950 how many cars had over head cams.
Mike aka the pirate

Bill, thanks for the manual. I got everthing this morning. You may not believe this, but, I went to school to be a mechanic on radial engines. It was the r-985 and they were used in the military on the UA-6 fixed wing aircraft. They are very unique, to say the least. That engine you have is areal collectors item. The first was made by Cross from 1929 to 1931. If I remember correctly, all of the large end of the connecting rods were connected at on place on the crank shaft. Why radial engines have odd number of cyliners is beyond me. Interesting: most radial engines were air cooled.

to ALL:

NEAT old outboard. - any idea at all about how many were built & about how much does it weigh?

fwiw, there was at least ONE 7-cylinder radial built out of a Jacobs 245HP aircraft engine, during the Korean War. - it weighed well in excess of 400 pounds!
it was, at least for a while, on display at the Chesapeake Bay Museum in MD, sometime in the early '60s. - i wonder where it is now???
(two MD watermen have told me that they saw it there, when JFK was POTUS.)

i do NOT know if there was ever more than one built, but that is the strangest/biggest OB that i can think of.

note: one of the waterman said that he believed that the OB was actually tested at Red River Army Depot, near Texarkana TX & that it may have had some parts actually built there.- i just wish that i knew more, but i don't.


yours, satx

That's what I was talkin' about. This is what I went to ASAVNS for. They were used in Korea. I guess that they were so dependable, they had some left for Vietnam. Notice the virable pitch prop. It was controlled by oil pressure. Those blades could turn while in flight!. Very hard to work on.

For me, these are an absolute work of art.

The Riley is certainly different for sure. Looks like a very "busy" engine, lots of plumbing, the odd starter setup, must be a generator on the portside.

I believe the starter is. It's a "developing" type of starter motor. I mean you don't just turn the key. There's too much compression. You flip a spring loaded switch up and wait 'till it builds momentum, then hit the starter botton. The black unit on the bottom is the carburator. The air intake is on the top. The're called updraft carbs. Major money. The chrome cowling that's next to the body houses the exhaust and you can see where the cylinders exhaust pipe joins the main pipe. Who ever built this airplane, put alot of time, money, and love into this project. I had a very unique experience with this aircraft. When I have more time, I'll share it with you. It will probably have to be on another thread.

Check this out! WOW

Holy Moly Batman! 10 large? Its rare but is the prop cast in gold?
They also put airplane type rotary engines in tanks. Just because they had tons of them around not because it was a great engine for tanks.

198tpi; All,

ImVho, that price is: NUTS.

yours, satx