electric golf cart motor mod on gas outboard
 

So, i have a 25hp outboard i am going to mod with a electric golf cart motor. I know the golf cart motor is about 4hp right now, and I wanted to see who if any of the folks in here have tried the same task and with what results. I will be working with a local company to fabricate the plate/shaft to couple the two pieces of hardware, but i want to make some tweaks to get the most hp out of it. what do you all suggest?

Over-volting it and keeping the current the same will result in higher rpm and should not damage it, within reason. The higher speed will have the fan running faster, so should be able to keep it cool despite the higher output. Keep the rpms reasonable, like under 5k.

The motenergy permanent magnet motors make for a more efficient and space saving way of doing it.

Sounds like you're already aware of the need to fab a new end plate with bearing and make a shaft. That's a lot of work to go with what may be an undersized motor anyway. What's the load? Series-wound DC motors are affordable and easy to find, and will give very fine control. A permag sized for a planing hull would be 'coggy' at low speed, though if powering a displacement hull, a permag or shunt motor could be very precisely-matched with no controller needed.