fuel tank

[martin47]

hi i have a 6m boat.. a 115hp murcury ( 1986 ) i am putting the fuel tank up in the bow...the fuel line will be around 5m long 1... will i be able to prime the motor with the normal inline bulb? 2 ...will the fuel pump cope over that distance ( 10mm bore ) also the tank i am fitting is 53L tank with a trough hull filler and a fuel gage...there are two fuel out let pipes......my other problem is that the bresther with this tank was in the filler lid witch is now a filler pipe ( trough hull ) as i am going to only use one of the fuel outlet pionts .can anybody think of any reason why i can not use the other with a lenght of pipe on it with a one way valve ...any comments will be most welcome .

 

[hkeiner]

Re: fuel tank

If you do what you are proposing, I suggest that you check for fuel starvation right after the change, as this might occur due to the longer fuel line. Mercury has published a Service Advisory that describes quite well how to test for fuel line starvation using a vacuum gauge.

Of course, someone that has actually tried something similar to what you are proposing with the fuel line would be able to give you a more definitive and useful reply in advance of your making the change.


http://www.marinepartsman.com/Mercury-Marine-service-bulletins/Mercury-Mariner/2001/EN_17.PDF

 

[achris]

Re: fuel tank

Hi Martin,

The previous poster mentioned using a vacuum gauge to check that the pump isn't being asked to do more than it can cope with.... That's correct. I've done this in the past, and you shouldn't have any problems. Yes, you can use the existing primer. 3/8" fuel line is the absolute minimum to use, I would use 1/2" up the the primer and then reduce it back to 3/8" there. I would also replace the diaphrams in the fuel pump. The diaphrams should be replace every year on the annual service anyway, but I don't know too many shop that do it.

The breather.... Just make sure that the pipe you are proposing to use does not go to the bottom of the tank, as a pick up does. You can't use a check valve in the breather line. It needs to be able to expel air as you're filling the tank, as well as allow air in as the engine is using it. Put the valve in and you will either kill your engine (by not allowing air to enter the tank) or have insufferable 'blowback' when filling (by not allowing air to exit the tank).

Cheers,

Chris.....

 

[j_martin]

Re: fuel tank

Racor makes a vent check valve that will keep you from splashing fuel out when filling, but let air in or fumes out freely as it should. It takes a little head room over the tank to work, but it does a fine job. It's called an LG50 fuel/air seperator.

hope it helps
John

 

[martin47]

Re: fuel tank

thank for all your advice...j martin thanks i will chek that LG50 fuel/air seperator.