The Scott had the best engine of any outboard. More power, etc. And smooth. When it ran. Ditto the McCulloch Outboard, chainsaw, and the Wajax pump. Reason is they were special aluminium alloy, I think with Berylium, and copper and could run hotter than most and far faster speed. The McCulloch engines in 1948 where the lightest per HP and fastest revving (12,000 RPm for the saw) ever made in the world. The 8hp Wajax pump motor weighed about 12 lbs. The Scott Atwater 40 was half the weight of the Evinrude, which ran half as hot. They demanded Castrol mix oil which was the only one high enough quality to make the engine last, and could run at half the mixture of a standard oil. They all had the same problem. The engines ran so hot that they developed vapour lock. If they did not run hot, they would not have been as powerful or efficient. Then when stopped they would never start hot because of gas bubbles in the carb. Had to cool them right down for restart. Chainsaw, pump, and outboard. Finally about 1975, far too late for McCulloch whose reputation had been finally eroded with the motor that would never restart hot, an Italian engineer solver the problem with the McCulloch saw, now owned I believe by Electrolux or some other outfit. It was too late. Woodsmen had abandoned the powerful McCulloch saw. It would cut wood about twice as fast as a Husky, but until the vapour lock problem was solved they were not desirable. The Homelite had the same problem BTW and it got a bad rep. I believe the problem was solved by a foot valve in the intake and a pressure equalization system into the tank i.e. a pressure feed carb-tank system with non expansion valves.
Today the formulations that prevented gas from boiling i.e. lower vapour pressure, higher boiling point, are absent and quite a few saws and cars with carbs have that problem all over again!
patentstorm.us
I owned a Johnson OK-75 1938 model 8.1 HP, also known as the Water Witch.
Seen on the left.
books.google.ca
EC<:-} |
