It isn't clear from your question if you only wanted to know the brand of the motor or it's hp rating...
If you are trying to figure out what hp motor you can safely run, here's a way to calculate the USCG approved max hp OB for your boat:
Hopefully this guide will help you calculate the maximum amount of H.P. your boat can be insured for.
- This is to only be used as a guide.
- You can round your final HP number to the closest multiple of 5. (31 HP would round to 30 HP. 33 HP would round to 35 HP)
Step One - Compute your Factor
A. Length of Boat x Transom Width (measure in feet: 14, 15.5,16, etc).
Step Two - Compare your factor to H.P. rating
A. 0-35 = 3 hp
B. 36-39 = 5 hp
C. 40-42 = 7.5 hp
D. 43-45 = 10 hp
E. 46-52 = 15 hp
Step Three - If your factor is over 52 (Choose only A or
A. With Remote Steering (steering wheel) and at least 20" transom height
Maximum HP = (Your factor x 2) - 90
Example: 19' 6" long , 7 feet wide = (19.5 x 7 x 2) - 90 = 183 (Round up in multiples of 5. This boat's max is 185 hp).
B. With Tiller Steering (hand or extension) or less than 20" transom height (Choose only 1 or 2)
1. Flat bottom, or hard chined boats (hull has hard angles)
Max HP = (Your factor x 0.5) - 15
2. Soft chine, rounded hulls
Max HP = (Your factor x 0.8) - 25
BTW: The only 2 pix of beeline boats in the library both show Mercs. If you're shopping for a period accurate motor, 1958+/-, I'd suggest a Johnson/Evinrude 30-35 hp.
It's close to what that formula above will probably give ya, and are great motors to work on, find parts/service items for, and look GREAT...
Plus I've probably seen 15-20 listed for sale in the last 4 weeks.
I LOVE the look of vintage mercs, but find working on them & paying for parts much more problematic..