Installing Moeller Plastic Fuel Tank ?'s

yknotgo

Seaman
Joined
Sep 8, 2012
Messages
51
I'm replacing my fuel tank with a Moeller 150 gallon fuel tank. I read that the tank needs room to expand, which I think I have covered, it's going to be close. Anyways, I got a belly style tank, but it the bottom doesn't fit flush I heard that a poly tank should not have void underneath it. So I was thinking of using expanding foam underneath it to make a solid floor for the tank. Also, would it be okay to use a couple 2x4's across the top to secure it from bouncing up and down or would that prevent it from expanding?

Second question is with grounding the tank. I want to make sure I understand it correctly. Do you run a ground wire from the fill on the boat, to the sending unit, and then from the sending unit to somewhere on the motor or a neg. post on a battery? Or am I wrong?

And the sending unit that came with the tank has a plug for the gauge. I haven't seen that before, but it's only my second tank I've seen, the first being the old one I pulled which just had a single wire coming from the center of the sending unit which I assumed was for the gauge. Anyways, is there a plug I buy to fit this one and if so, how do I hook it up, or do I need a new gauge? Or do I cut the plug off and splice, but if that, how do I splice it?

Thanks for any advice,

Grady
 

yknotgo

Seaman
Joined
Sep 8, 2012
Messages
51
No Title

Here are a couple photos.
 

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UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
The instructions for installing the tank should be provided in the with the tank. Else, check the Moeller web site.
If the tank has mounting grooves, Moeller 035710 Clips can be used. Else Moeller 035711 Straps can be used for all tanks.
The tank will swell and shrink 3% as the fuel comes in contact with the plastic. A very small but significant amount of the hydrocarbons in the gas are absorbed into the plastic and cause it to swell. An empty tank will shrink somewhat over time as the absorbed hydrocarbons evaporate back out.
No! this is NOT an Ethanol issue. It happens to the tanks with all fuels. Do NOT use Foam. And allow space and drainage under the tank for the inevitable water that will get in or pass through there from forward in the boat. The compartment should have Limber (Drain) Holes.

The two pin connector, is your sensor wire and the ground wire to the sender.
If you do not have the correct connector in your wiring harness, you can remove the connector, and splice as needed to match the current harness.
As long as all metal fittings on the tank are connected, either individually, or as a group, to either the battery, or the engine block, you will be grounded.
,
 

yknotgo

Seaman
Joined
Sep 8, 2012
Messages
51
What is wrong with using foam to create a floor structure for the tank? I'm not talking about foaming in the tank, I'm talking about just creating the floor. I could build one out of plywood, just not understanding why the no foam. As far as drainage, the fuel compartment is isolated so no water should get in if properly sealed. If water does get in, it cannot drain anywhere.
Thanks for the tips and advice.
 

smokeonthewater

Fleet Admiral
Joined
Dec 3, 2009
Messages
9,838
I suggest that you contact moeller and ask them about the foam thing and ALSO I would order a matching plug for the sender and splice it to the boat wiring.
 
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