1969 40hp Evinrude

[Iocus]

We have acquired a 1969 40hp Evinrude. Does anyone know what the Drain Valve assembly is for? We have a maintenance manual but can not find any information as to what it does. We are having trouble getting the engine to run despite having a good spark and plenty of fuel at the carb but very little in the engine. The reed valves open when squirted with aerosol (easystart). It looks as if this drain valve is between the reed valve and the inlet port but the diagram does show it clearly. Also does anyone have any good advice as to how to get the cranknut off to gain access to the points and magneto as ours refuses to budge using a socket and long bar. What is the best way to stop the engine rotating whilst trying to undo the nut?
Many thanks in advance

 

[Cliveshep]

First, are you sure the nut isn't a left hand thread? Flywheel/crankshaft design usually alllows for the nut to be tightened in the OPPOSITE direction to engine rotation so the forces keep it tight and not spin it off.

Second, go buy yourself the correct socket (unless you have one) and beg/borrow/steal/buy and impact driver. Most motor factors keep those.

All you then do is set it for the direction you want the nut to go (see point one) and whack it good and hard with a lump hammer. The spiral action inside the tool transfers vertical blows into a very small rotational movement but with big force.

Keep punishing the tool until the nut turns.

This is also the method for tightening it but don't over-tighten.

To assist, heat the nut only with a heat gun or blow-lamp, don't heat the flywheel as the heat reduces or destroys the magnet's efficiency inside.