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Atco Boatimpeller

Atco Boatimpeller as found
Atco Boatimpeller restored

Atco is/was one of England's premiere lawn mower manufacturers, herewith the Atco Boatimpeller! The name Atco was derived from the Atlas Chain Company and owned by Charles H Pugh Ltd of Birmingham. Looking to expand their horizons, someone at Atco in the late 1940's must have thought it was a good idea to get into the outboard business.

With the likes of Anzani and Seagull already in the frey, Atco came up with what they thought was a better mousetrap. The straight drive concept was not a new design unique to Atco. A French firm had tried it in the early part of the century and here in the USA the Caille outboard company had some success with their "Liberty Drive" outboards in the 1920's. Even today outboards are made in this configuration and used in many places in the world; Bayou country, South America and in parts of the orient. The advantage of the straight shaft outboard is that it can run in very little water, ideal if you live in a marsh, swamp or estuary - England has a lot of these! Atco claimed you could run the motor in as little as 4" of water. They went on-sale in the UK in 1948 or '49 and I don't think they exactly set the world on fire. The bulk of the owners who have corresponded with me are in former British colonies like Australia, New Zealand, South Africa and the like. According to my Abos Guides and other material, they went on sale here in the USA in 1950.

The powerhead is a 79cc air-cooled affair made by the venerable Villiers firm. It is the same type of 2-stroke unit that Atco and many other companies used on lawnmowers, pumps and even scooters! The magneto and carburetor appear to me to be the same as used on the Seagulls of this period. I am running the motor on a 16:1 mix of air-cooled 2-stroke oil to each gallon of gas but the original instructions call for 3/4pt of oil per 2-gallons of petrol.

Originally fitted with a Champion "17" sparkplug, this translates into a modern D-9 Champion plug gapped at .025". You can set the points without removing the flywheel, simply remove the rope plate and cover. The points should begin to open about 5/32" before TDC (measured by piston travel) and .020" is the point gap. Should you need to remove the flywheel for some reason, the flywheel nut is also a puller. It will rotate about 1 turn loose and then with some extra effort, pull the flywheel off the shaft. The magneto plate is not adjustable and the flywheel is not keyed so timing must be set with the motor at TDC - replace the flywheel with the arrow on the base plate and flywheel lined up.

While only rated at 3/4 horsepower, the Atco Boatimpeller weighs in at a hefty 44lbs - this could be the heaviest power-to-weight ratio of any outboard I own! The Atco starts with a tug or two on the starter rope and a bit of juggling the choke but after a minute or two it settles down & runs well. Out on the water mine does not make a great deal of power, but then I must remind myself that it is only rated at 3/4hp! When in use the prop "thrust" balances the weight nicely so you can let it seek its own level, there are also "slots for altering the disposition of weight" on the transom bracket if needed. While running I found it to be very pleasant to use, quiet and smooth.

A major shortcoming of the Atco is what to do with it when not in use. When not running it just dangles straight down off the transom. At the dock of our test-site it would ram down into the lake bottom when waves rocked the boat. Laying it cross-ways to the transom had several feet of the leg sticking off the side of the boat, not very considerate to my dock-mates. And I managed to burn the heck out of my hand swinging it into the boat one time, that cast aluminum muffler is an attractive (but dangerous!) grab-handle. On land transporting the Atco is a pain, it is very ungainly and prop heavy. There is a large nut 1/2 way down the shaft that when loosened allows you to slide the bottom 1/2 of the leg out making it slightly easier to transport. But even apart, the top powerhead part is not easy to portage - and again, a warning about that hot muffler if the motor was just run! I have corresponded with two Atco owners who lost their lower units overboard when the bottom slipped its moorings while in use - PLOP!!!

A big thanks to John A. who rescued the motor from the dump and gave it to me - it was the best present I received all year! Also to AOMCI member Bob G. who kindly sent me a copy of the owners manual and parts list - many of the facts above were gleaned from it!

If you have one of these outboards, drop me a line by clicking the Contact Me link at the top of this page. I am curious to know your thoughts on it.

1951-2 Atco Boatimpeller Model 804

Year & Model: 1950-2 Atco Boatimpeller 804 (also referred to as the Model 79 and "Junior")
Horsepower: 3/4
Bore: 45mm
Stroke: 50mm
Ignition: Villiers
Point Gap:.020
Cooling: Air - passive free flow
Condition: Unrestored
Retail price when new: $125.00 (USA)
Weight: 44 lbs.
Oil/Gas Mix: 3/4pt TC oil to 2-gallons petrol
Spark Plug: Champion D-9 (Modern)

See my comments on running the Atco above.









Here is are some links to other sites with information on the Atco Boat Impeller.

Atco Boat Impeller

Saving Old Seagulls - Non-Seagulls (Scroll down on this page)

Post Script - If you are interested in seeing Atco's lawnmowers from the time the Boatimpeller was made visit the link below. They are decidedly different from the Evinrude Lawn Boy and Locke mowers I grew up with!

Old Lawnmower Club UK - Atco 1950's

About the Decals

In refinishing the tank and stripping away the years of paint slopped on it by the motors previous owner(s), I was stunned to have the following evidence show up! I inspected them with a magnifying glass but was unable to determine the color of the words. The tank was painted a warm white, a touch lighter than the background on this website.

I received an email from one owner in Australia who sent me a great file showing exactly what the decal should look like and that it was dark green! Here are some before & after photos.

You can click on the images to supersize them!

ATCO = 1" tall and 3 1/4" from the tip of the "A" to the end of the "O"
BOATIMPELLER = 3/8" tall and 4 1/2" from "B" to "R"

Restored motor below

My friend Bob G. has the pump attachment for his Atco. He let me borrow it, here is a photo of the unit and one of it in action. The attachment slips on in place of the lower leg and prop. It works okay, maybe a bit more volume than the Scott Atwater Bail-A-Matic. (And a lot more reliable!)


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