Mercury 115 or 150 for a 20 SF?

[Cape Codder]

Hi All,

I am considering repowering my 1975 20 SF with a new Mercury four stroke.
I'm currently running a 1993 150 Mercury Black Max and am happy with the performance overall but it chokes out a lot at lower idle which is why I'm considering a repower.

I was looking at the Mecury 115 with a big gear case because it's closest in weight to my current motor until my local mechanic suggested going with a 150 Mercury four stroke. The batteries have been moved under the console and I will be raising the transom with the repower so it can hold a 25" shaft. Everything else is original.

Any suggestions on which way to go?

The new 150 with a 20" shaft is 455 lbs
The new 115 with a 20" shaft is 359 lbs