How big gas tank for kicker?

[Grant Brown]

I just installed a Yamaha 8hp High Thrust on a 2008 Bayliner Discovery 210 cuddy.
I plan to use a small auxiliary tank instead of plumbing it into the main tank.
Does anyone have any recommendation on fuel tank size?
Thanks
Grant

 

[ondarvr]

It all depends on how much you use it and how often you want to fill it. At trolling speeds an 8hp Yamaha sips gas, crank it up to get home when the main fails and you won't get nearly as far.

 

[Grant Brown]

My choices at the local stores are limited. I am looking at either a 3 or 6 gallon.

 

[Bondo]

Ayuh,... So what's yer intended usages,..??

 

[Grant Brown]

1) Trolling for salmon in the ocean near Vancouver.
2) Emergency get home power if the main were to die for some reason (boat is very well maintained so not a huge worry).

I found this site here (http://www.boat-fuel-economy.com/yamaha-small-outboard-fuel-consumption-4-5-6-8-9.9-15-20-hp) that puts it at .85 gph at 5500 rpm which sounds like WOT to me. So a 3 gallon tank would get me 3.5 hours. Not sure what to expect for speed from a 3500 pound 21 footer with a 8hp High Thrust, but I imagine hull speed is around 5mph. So I would roughly have a 18-20 mile range on 3 gallons.
Make sense to anyone else or an I talking out my arse?

Grant

 

[ondarvr]

I'd just go with a 6, that type of trolling will take more fuel, and if you need to get home on it you won't have much left.

Or just plumb it into the main tank, some people don't like it that way, but it's commonly done.