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Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 2:33 pm
by Adaptel
Hello All,
I have a 2001 Carver 356 and I find is incredibly strange that the generator is setup so that it always draws fuel from the port tank only. My boat as an aux fuel tank under the swim platform and it just makes sense that the generator should get its fuel from there to prevent imbalance from running generator. Both propulsion engines have a fuel selector valve to select either main side tank or aux tank, but generator is always port tank. Why?!?!?!

I was thinking of re-configuring this by adding a third fuel selector valve for the generator to select aux or port tank. Is there any reason for not doing so? Common sense is telling me that I would need to install another fuel line, pickup tube, and anti-siphon valve on the aux tank to prevent fuel starvation by tapping into existing fuel line. Is this correct? Any thoughts?

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 2:47 pm
by Tireless
The Genny taking fuel from the Port saddle tank is a normal thing for Carvers, and possibly other manufacturers as well. It has never caused me any issues over the years, due to a fuel imbalance. I have a fuel transfer switch/line to balance the saddle tanks, but I have never used it.

In addition, when I refuel, whether partial or fill up, I always ensure the tanks carry approximately the same level.

The fuel consumption of the Genny is so minimal, it is difficult to see a significant difference.

As for putting in valves to have it draw from your aux. as an option, not sure the end would justify the means, however, that is entirely up to you.

I wouldn't even consider that expense on my boat and we use our Genny a lot. JMHO...

Greg

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 2:47 pm
by Tireless
The Genny taking fuel from the Port saddle tank is a normal thing for Carvers, and possibly other manufacturers as well. It has never caused me any issues over the years, due to a fuel imbalance. I have a fuel transfer switch/line to balance the saddle tanks, but I have never used it.

In addition, when I refuel, whether partial or fill up, I always ensure the tanks carry approximately the same level.

The fuel consumption of the Genny is so minimal, it is difficult to see a significant difference.

As for putting in valves to have it draw from your aux. as an option, not sure the end would justify the means, however, that is entirely up to you.

I wouldn't even consider that expense on my boat and we use our Genny a lot. JMHO...

Greg

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 2:48 pm
by Tireless
Not sure why the post went through twice. Lol.

Greg

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 3:12 pm
by Adaptel
Tireless wrote:Source of the post It has never caused me any issues over the years, due to a fuel imbalance. I have a fuel transfer

The fuel consumption of the Genny is so minimal, it is difficult to see a significant difference.


After really hot weekends when I run my generator a lot, I definitely have a very noticeable fuel imbalance between port and starboard tanks, and have to either run the starboard engine on the AUX tank until balanced....or get some fuel prematurely. My boat does not have a transfer valve/switch. Was that an optional feature, or added after a certain year?

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 5:33 pm
by km1125
You can certainly add a dual tank setup for the generator, but note that the generator draw tubes from the tanks are typically shorter than the engine tubes, so that the generator can't draw the fuel down to a point where the engines can no longer pull fuel. Typically you need at least 1/4 tank to reach the bottom of the pickup tube for the generator.

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 7:16 pm
by tomschauer
Only diesels had the fuel transfer option.
As mentioned, it's pretty standard for the carvers to pull from port tank only.
I have always planned to put in a selector and run my genny from the aux tank but never did. On the few occasions I run the genny enough to make a big difference, I switch the port engine to pull from the starboard tank for a bit if I don't plan to refuel soon.

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 7:27 pm
by Viper
I added a tank selector option for the genny on a 355 years ago. As long as it's done properly, there should be no ill effects. Just make sure your new pick-up tubes only go down to three quarters of the tanks as km mentioned above. You'll need a three way valve with an off position if you want to access all three tanks, and don't tap into an existing line, they need to be dedicated.

Unless you boot around all the time at high speed, you can run both engines off one tank, the one with the most fuel, until it's even with the lower tank.

Fuel transfer pump options are on diesel applications only.

Re: Why does genny draw fuel only from port tank?

Posted: March 7th, 2023, 7:30 pm
by g36
If your set on running another fuel line why not tap into the stbd side. My 405 gas boat has a selector for either port or stbd. This will much simpler than running a line to the aft tank and probably will be much less frustrating to get too compared to the aft one.

Re: Why does genny draw fuel only from port tank?

Posted: March 8th, 2023, 7:46 am
by buster53
Just switch the port engine over to the aux tank for a while to maintain saddle tank balance. 10-15, even 20 gallons of gas difference between the saddle tanks is no big deal. Don’t sweat the small stuff.