Converting Madeira 40 to Madeira 50 (Part 1)

When I did the carburetor cleaning some weeks ago I noticed that my outboard was Madeira 40 although it had Madeira 40 XS decals.

I have been playing with the idea how to convert this outboard to 50 HP and been studying the part listings.

This is what you need to change (I suppose):

• Both carburetors need to be replaced (going from Dellorto 34/30 to 38/34).
• The intake manifolds, those are the parts where reed valves are attached to.
• The engine head is different.
• Luckily there is no exhaust separator plate in Madeira 40 so no need to remove that!

I finally convinced myself that let's do the carburetors and intake manifolds and see what happens. The engine head of 50 HP model most probably gives more compression, I don't know how expensive that is but one can get similar results by shaving the engine head, I may want to try that later.

I was not able to find second hand carburetors so I decided to order new ones from Engine Marine Part. This conversion is not financially very well justified as the new carbs and intake manifolds costed around 800 € plus shipping 😂.

This is the upgrade plan:

1. Remove the air box
2. Remove Dellorto 34/30 carburetors.
3. Remove Madeira 40 intake manifolds.
4. Remove reed valves from Madeira 40 intake manifolds.
5. Remove tubes and plastic connectors from intake manifolds.
6. Attach reed valves to Madeira 50 intake manifolds.
7. Attach plastic connectors and tubes to Madeira 50 intake manifolds.
8. Attach Madeira 50 intake manifolds, connect oil tubes, and two air? tubes.
9. Move fuel connectors and linking arms from old carburetors to new ones.
10. Attach Dellorto 38/34 carburetors.
11. Connect fuel hose.
12. Make sure that carburetors are synced and closed at idle. Adjust idle and mixture.
13. Put the airbox back.
14. Start the engine!

Stock Selva Madeira 40 intake manifolds.

Madeira 40 intake manifolds removed.

Reed valves still attached to Madeira 40 intake manfifolds.

Reed valves and connectors moved from Madeira 40 intake
 manifolds (lower items) to to Madeira 50 intake manifolds (upper items).

Link arms, fuel connectors and all other stuff
moved to Dellorto OVC 38/34 carburetors.

The new intake manifolds attached.

The new carburetors attached, testing WOT throttle position.

The carburetor change operation completed.

First startup after the carburetor change, maybe it's a little bit more angry! 😎

Check also Part 2