Proper way to run main & kicker outboard off 1 gas tank?

[buckeye_sean]

This may seem absurdly silly to some - just thought I'd ask before I do something I'd regret.

My 17' Fisher Deep-V has a 30 gallon internal tank which runs my 90hp Merc. oil-injected 2-stroke. I always carried along a 6 gallon tank with mixed fuel for my 2-stroke kicker - it was not injected. I just replaced the 2-stroke with a Merc. 4-stroke 9.9. I want to run both the 90hp and the 9.9 off of the internal tank.

Do I...

1. Manually switch the 1 fuel line between the motors as needed?
(Seems there is a better way to do this.)

2. Split the fuel line with some kind of "Y" fitting? If yes, do I need a primer bulb on each end? Also, is there any harm in running a 2-stroke and a 4-stroke off the same fuel source? I have an in-line glass fuel filter on the fuel line and I have seen the 2-stroke oil tends to "back-feed" a little bit into the filter.

Again, sorry if this sounds silly - just never done it before.

 

[QC]

Re: Proper way to run main & kicker outboard off 1 gas tank?

Q. Proper way to run main & kicker outboard off 1 gas tank?

A. Don't . . . (you want to keep the fuel supply separate in case you need the kicker to get you home and the problem with the main is fuel related)

 

[tashasdaddy]

Re: Proper way to run main & kicker outboard off 1 gas tank?

totally agree, contaminated fuel, both motors are contaminated.

 

[buckeye_sean]

Re: Proper way to run main & kicker outboard off 1 gas tank?

Hmmm, OK I see your points - but I know I've seen guys running their main and kicker off of the main fuel cell before. Matter of fact I know I've seen brand new Lund Deep V's rigged that way at my local marina.

 

[tashasdaddy]

Re: Proper way to run main & kicker outboard off 1 gas tank?

sure you can do it. but you are compromising you back up motor. just put a "Y" in the fuel line, you need primer between Y and both motors.

 

[F_R]

Re: Proper way to run main & kicker outboard off 1 gas tank?

Best to have separate fuel lines, and pickups in the tank. Easiest to swap connector to whichever motor you are going to run. There is a reason: With a T fitting, if you intend to run motor "A" and the fuel is low in the carburetor on "B", the float will drop down and then "A" will suck air through "B"s open float valve because that is easier than lifting fuel from the tank.

Edit: A tank selector valve instead of a T is OK because it isolates the second motor. Just switch the selector valve to run the other motor. This actually is the way it's usually done.

 

[Nandy]

Re: Proper way to run main & kicker outboard off 1 gas tank?

Running both your motors off the same tank and sharing the hose is akin of having a main bilge pump and the secondary pump running of the same battery and same wires. It can be done, but if the problem is the power source (gas in tank or battery) or the delivery (shorted fuse, open in cable, defective clamp/hose) you will be down in your luck. Better to run you spare gear as undependable of the main gear as possible.
Good luck.

 

[Backlash]

Re: Proper way to run main & kicker outboard off 1 gas tank?

There is definately a point to be made regarding the contaminated fuel. But I've been running my oil injected 150 and my 9.9 4 stroke off the same built in tank for four years without a problem. I used a "y" fitting at the tank. The primer bulbs on each line keep one engine from drawing fuel from the other.
Backlash

 

[crb478]

Re: Proper way to run main & kicker outboard off 1 gas tank?

If you are determined to run both off of the same tank you can get a water separating filter that has two outlets built into it and run a separate line to each engine. If you do that I would still keep a separate small tank(filled) available for emergencies and dump it into the main tank on every refill.