What is needed to convert short shaft to long shaft

[skiper517]

Hello – just purchased 1957 35 hp big twin Evinrude short shaft. I want to convert this to a long shaft. Can someone please tell me what parts/work are required to do so? I don’t know how long the long drive shaft has to be. I have the 5inch extension already. Thank you so much!!

[frankr]

The drive shaft will be the same in every way, except exactly 5 inches longer. You will need a water tube extension, and a long shift rod connector. Also the large bolt in the rear, 5 inches longer. And 6 more small bolts.

[skiper517]

Thanks for the quick reply. Being new to this can you tell me what the standard length of the motor shaft is? I don’t know how to look for the size not knowing what is standard vs. longer.

[jcrigan]

I have one here that goes on a 1959 35hp. It’s 32.5" long.

[1946zephyr]

Just a little pointer here. The super quiet style extension housings won’t work on the older single wall style Big Twins. All the other parts will work fine, but the extension housing is a different shape, towards the rear, where the large bolt goes.

[frankr]

’57 impeller is driven by a round pin. ’59 is driven by a Woodruff key.

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