Johnson P-30 connecting rods: top or bottom

[hirschlt37]

Restoring a 1926 P-30…..and everything is going great; right & left  cylinders/pistons. But now for final assembly: as you face the motor…which connecting rod goes on top and which on bottom??  I never thought about this….if you look into the situation they seem to be interchangeable?? I’m thinking it doesn’t make a lot of difference…or did I miss something?

[Tom]

It does make a difference.  If it’s wrong, you get spark when the pistons are at the bottom of the bores.  Pistons should be at top dead center with the keyway pointing to the arrow cast into the top of the crankcase.

Tom

[hirschlt37]

I understand that, I’m talking of where they connect to the crankshaft….

[Tom]

Are the pistons still attached in their original configuration?  If so, the longer slope goes toward the exhaust port.  If you are just looking at bare rods, I don’t think it makes a difference.  Best to check in both configurations to see if one binds up.

T

[hirschlt37]

You are correct….I apologize…when I thought about it, the arrow will place the crankshaft in the correct position, and when I install the piston/rod assembly for TDC that will determine the connection to the crank.  Right?  I did check binding and they are OK.

[Tom]

Yep.  Evinrude is similar on early twins, except the keyway points forward.  This would be on N Sportwins and R Fastwins.

T

[hirschlt37]

Thanks for your…much appreciated…

[Tom]

Great motors, they run pretty well.  Good luck!

T

[hirschlt37]

Another question you can likely help with…the piston pins are pinned to the piston with what I believe is a cotter pin. Correct?  After inserting it, how do you spread the pin legs?  Just get creative?

[Tom]

I usually go through the hollow piston pin with an awl to get it started, then a screwdriver to set it.

T

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