British Seagull 40 plus

[Basil]

I picked one of these up a while ago with plans of building a miniature version. They were known for being an inexpensive very (some what) reliable early outboards and have a large diehard following. They were manufactured in what is now my hometown of Poole, Dorset. UK. Just lately my interest has been sparked again on this little project. First I am going to draw the whole thing up in CAD that way I can a general sizing on everything. This is where I am up to so far. Scaling looks like it is going to be around 40% or 2.5 to 1. They are a small capacity to start with and scaled this works out to about 4cc which I think I can bump a little. There will be a few new challenges along the way. Part of the attraction I guess.

 

[GreenTwin]

My dad had one of these on his skiff, and I used it many times.

Rock solid little motor; simple and robust; never had a second's problem with it.

My brother-in-law still has my dad's Seagull.

As I recall, it had a cast iron cylinder, and perhaps a spring-loaded prop.
And I seem to recall it had a lot of stainless for salt water operation.

Great memories.

.

 

[Basil]

I would definitely have to agree. At first inspection they seem awfully crude by todays standards but like so like many things of a bygone time, these units are so simple and basic in design that with few tools and very little knowledge they can be made to function quite satisfactory and reliably.
The KISS principle certainly applies here.

 

[scottyp]

Cool project, I have the same idea for a Johnson A-25 or similar outboard someday.

 

[Basil]

A little catchup to where I am at with the British Seagull CAD. Slow going but good practice and fills up the evenings.

 

[GreenTwin]

That is some 1st rate 3D modeling and rendering.
I am too lazy to do rendering, and my 3D package won't do it anyway.

Fabulous work you are doing on this outboard !

.

 

[Basil]

That is some 1st rate 3D modeling and rendering.
I am too lazy to do rendering, and my 3D package won't do it anyway.

Fabulous work you are doing on this outboard !

.

Thank you. Probably tackle the magneto next.

 

[Steamchick]

Back in the 1970s I owned a Solent Seagull 16ft sailing Dinghy (from c 1932), so in keeping had to use a (1960s) 2HP Seagull outboard when motoring.
What a reliable (not powerful) beauty!
As long a fuel was good, correct 2-stroke mix, with a good spark-plug, it was always "first pull" starting, and just ran until I stopped it.
Not as quiet or refined as more modern designed Yamaha outboards of similar sizes, but robust when rinsed in a fresh water tank and then started again after winter, stored in a dry garage... In Spring, fresh fuel and a couple of pulls and it was away again.
Fond memories!
K2

 

[Niels Abildgaard]

What Seagull model can be had today for what price?
I am dreaming of making a side-exhaust-valved two stroke.
If the nessecary cam sits just over the seal for crankshaft it will swim in oil.

 

[Steamchick]

To what advantage over a cylinder ported exhaust?
K2

 

[Niels Abildgaard]

To what advantage over a cylinder ported exhaust?
K2

Better fuel economy and less noise.
Maybe

 

[Nikhil Bhale]

2 stroke engines with exhaust valve are common in marine industry. Generally all ocean going ships have a 2 stroke engine with turbocharger and exhaust valve with uniflow scavenge. Exhaust valve gives good scavenging efficiency with less mixing of exhaust and fresh air.

 

[Basil]

What Seagull model can be had today for what price?
I am dreaming of making a side-exhaust-valved two stroke.
If the nessecary cam sits just over the seal for crankshaft it will swim in oil.View attachment 156333

Most used models of the Seagull seem to be relatively inexpensive. Anywhere from £50 to £200.
An interesting take on the standard 2 stroke design , the main advantage I guess would be the ability to have non symmetrical exhaust timing events. Fuel efficiency and noise being the criteria.
Certainly worth a build and a play.