What size fuel tank to buy?

[pauldconyers]

I have a 14 foot jon boat that I added a deck on the front and back to so the weight is more than you'd think. I have been running it only on a trolling motor this year but just bought a 9.9 hp outboard for it. Trying to decide what size gas tank to buy. Looks like I would probably be deciding between 3 and 6 gallon tanks. The 3 would certainly fit and I'm pretty sure the 6 would as well. I would never run it on big bodies of water where I needed to run it for a real long time or anything. I just don't have any personal experience with how fast I would burn through gas with a boat of this size/weight with a 9.9 hp motor and would appreciate some help here. TIA

[Way2slow]

If you go for a full day and do much running around, a three might leave you short.  There's been numbers of times I've run three or four gallons in a day.

[NYBasser]

Always go bigger than you need to so you wont have to worry about running out.

[WRB]

Is the 9.9 hp a 2 or 4 cycle engine?

Weight figure 6.5 lbs per gallon and about 1 per hour at 3/4 throttle for 2 cycle. If you mix oil to gas for a 2 cycle get the 6 gallon, you don’t need always fill it full!

Tom

[NoShoes]

My old boat was a 1448 with a 25 hp Yamaha. I used to fill up a 6 gallon tank and it last full weekend fishing trips. 3 days of fishing would be running on fumes. 

[lo n slo]

i have a 14’ johnny with a 15 hp tiller and a 3 gallon tank. my advice is to go with the 6 gallon. 

[GreenPig]

My new 9.9 4 stroke came with a 3 gallon tank and I've been told to ve surprised how long it'll run on it. You may also want to consider the 6 for weight in the rear to keep the boat level while fishing from the front deck.

[Bankbeater]

Get the 6.  I've ran out of gas before on the lake. It's no fun paddling back in open water. 

[Johnbt]

I have a heavily loaded 1648 and a 9.9 Merc 4-stroke. I'm still using the 3-gal tank that came with it, but I always have a full 1-gal can with me. It's $15 worth of insurance that I won't have to paddle to shore.

 

[VolFan]

Never heard someone say "I wish I had less gas".

I have a 20 hp Merc and a 6 gallon tank lasts me a few trips. If you fish multiple long days and long runs away from a fill-up, get the 6. If you're day to day or short trips, the 3 should be fine.

[TnRiver46]

On 12/14/2020 at 8:08 PM, lo n slo said:

i have a 14’ johnny with a 15 hp tiller and a 3 gallon tank. my advice is to go with the 6 gallon. 

Yeah but you’ve got that thing loaded down with bullet sinkers for Texas rigs 

 

to the OP, You say you won’t be running it for long periods. If this is true 100% of the time, the 3 gallon will be fine. But like everyone said a bigger one will allow you to drive further or maybe one day try bigger waters. The main factor on fuel economy: is your 9.9 two stroke or 4?

[Maggiesmaster]

I’ve got a 4 stroke 9.9 hp on a 16 ft. boat, and my 3 gal tank is more than enough.  One disadvantage of a 6 gal tank is that you’ll probably leave old gas in the tank. If you fill a 3 gallon at the start of the trip and run out, the lake’s too big for a 14 ft. Boat!

[Teal]

Get the 6.   You can always fill it half way and still have 3.  Cant do that with a 3 gallon tank.   Late in the year, just fill it half way if you dont want alot of old gas left in it.  

[Bluebasser86]

I've got a 15hp 2 stroke in mine and use a 3 gallon but I rarely use the gas motor except one or two short runs a day. If that's all you'll do, you could get by with the 3, otherwise I'd get the 6.

[lo n slo]

19 hours ago, TnRiver46 said:

Yeah but you’ve got that thing loaded down with bullet sinkers for Texas rigs 

smh

know’s me like the back of his hand 

[haggard]

Consider running a 3 gal because it fits/stows better, and carrying a 2.5 gal jerry jug as backup.

 

I'd guess the 9.9 would do well on a typical outing without running out (I run a 15 hp on a 3 gal on a 900 acre lake).

 

The additional 2.5 gal in a spout-style jug (not typical marine tank) is good backup (pour it into your primary tank) and should easily get you back the distance you went out, plus it can be moved around easily in the boat so you don't have a full 6 gal weighing down the boat all in one spot.

 

Also can help out another boat more easily if they run out of gas. Or if your truck does. It's versatile.

 

Downside to refueling your primary tank on the water is you have exposed gas and fumes, on a boat that's bobbing around. "Please extinguish all smoking materials at this time. This is your captain speaking."

 

 

 

 

[Mbirdsley]

5 gallons is what I would get.  I had 9.8 merc 2 stroke on  a 14 ft mirror craft deep-V.  If I was just fishing smaller to medium sized lakes a tank would last 4 trips or more .  If I was on a river or Saginaw bay  doing a lot of running around every 2 trips