Lengthening fuel hose and battery cable?

[Petepounder]

Hi gang-

This looks like its going to be a great forum to belong to. I just purchased a used, 2005, Honda 25. I want to put the portable fuel tank in the front of the boat to help offset weight as well as putting the battery well forward. The manual says not to run the fuel line over 6 feet. Can I do so if I increase the fuel line diameter? I want to run the fuel line about 14 feet. Any help on this or increasing the length of the power cable to the battery will be greatly appreciated

 

[tashasdaddy]

Re: Lengthening fuel hose and battery cable?

i don't think increasing the size will help, but placing the tank on a pedistal (basically as high as you can) an run the fuel line low creating a siphon effectout of the tank will help . i have 10' of hose on an old evinrude pressure tank and have had no problems. going 14ft with the battery you ned to increase the size of you cables. if you have #4 cables id go to #2. this just make sure you don't get a voltage drop from the length. welcome to iboats. we like to have Brits as members.

 

[Texasmark]

Re: Lengthening fuel hose and battery cable?

I'm going to butt in tas.

I think that with his 25 hp his current draw is going to be like in the 50 amp (or less) region and #4 should do him.

I think 4 will carry 50 amperes 50 feet with a 2% drop at 100% duty cycle. Don't have my book but that should be pretty close. Besides, the line drop is caused by copper resistance increasing due to heat......like in continuous duty.

Starting an outboard is very very intermittent and the engine should start before the wire even knows it got smacked.

I like to keep the cable as small as is reasonable due to the weight.

On the fuel, gotta ask yourself why the distance limitation. Seems to me that it's the same sort of thing you have with electric wire. The fuel pump has a specified suction pressure (vacuum). If you offset distance by increasing diameter, you will be offsetting the drag caused by the distance increase. Remember area is the second power (square of the radius x pi) so you don't have to double the dia to halve the loss.

And, if you can elevate it without a lot of hassle, that's just more in your favor.

My 2c

Mark

 

[Texasmark]

Re: Lengthening fuel hose and battery cable?

Sounds about right. My experience with things of the sort (fuel lines, water pipes) is that the next size up is twice the AREA of the predecessor; hence twice the SIZE.

Mark

 

[WillyBWright]

Re: Lengthening fuel hose and battery cable?

Stay with the same line size and make sure it's a nice level run from the tank to the transom then about straight up to the motor. Increasing size will add to the amount of work for the pump as there's more fuel weight in the line to move. If anything I'd go smaller. Avoid dips and valleys in lhe line. I had one customer run it from seat to seat to seat making hills and valleys to oveercome. Also do not put the line at a diagonal from the tank to the motor. Again it's a weight issue. You'd be pulling all of the weight of the gas as opposed to the few feet of gas from the floor on up. It would only be a problem if you troll with it. If the pump is getting plenty of RPMs, it's not going to be a problem.