If you want it to run the way it was supposed to run with all stock equipment then you will need to be prepared for about 15 MPH maximum which is very slow. Don't pay some hobby shop guy a dime for that. I would suggest you do as most people with the ABC Super Hawaii or CESA boats do and get rid of those slow dual motors and convert it to a single real 700SC motor on a flex shaft out to a strut/rudder set up. You could initially try to use the steerable stock outdrive (instead of the strut/rudder) but the 700SC motor's power will destroy it fairly quickly. On 14 cells you should get around 28-30 MPH with a 45mm prop.

Just so you know, those stock motors say 700RST on them but they are 500 series motors and way too weak for a 40" boat.

If you can rebuild motorcycle engines, you can easily re-do a CESA. It's just not that hard and there are plenty of people here that will help you at each step. It will take you some time and some money to do but it's a fun process. I know, I've done it twice with these hulls.

Here are some pictures that may inspire you: