TOPIC: Installing permanent tank in 73 Crestliner Muskie

Hi All:

I am in the process of installing an aluminum 18 gallon fuel tank in my 73 Crestliner Muskie 15 with 65 HP Evinrude outboard. Tank is 30 x 15 x 9, so it fits under the rear splash area with no issues. Tank will be offset to port, opposite the battery, so should balance out well (and still allow access to bilge well).

Here are my questions:

I am grounding the tank to the battery negative with 10 gauge stranded wire - also attaching the ground wire for the new Moeller 9" reed fuel sender to the grounded lug on the tank). The filler is plastic body (no metal or chrome), so no need to ground it. Do I need a ground plateon hull of boat, too (or is outboard motor enough ground)? This boat will be freshwater use only, and probably fueled only on trailer (not on the water). The filler is self vented, so that is taken care of.

Fuel fitting is 3/8", with anti-siphon. Anything special needed here? I plan to add a water separating filter soon.

Tank is in excellent (like new) condition, with no corrosion (sparkling clean inside, too). Was made by AFP in Florida. The previous owner had added an extra fuel fitting low on one side (not reinforced, just threaded through the 1/4" aluminum. I had a local aluminum fabricator shop weld over the hole, so now no problem to worry about.

Anyone see anything missing? I did this because I am just getting too old to want to pick up two 6 gallon removable tanks every time I go out (plus, 18 gallons fit in less space than the two 6 gallon OMC tanks took. I will post some pics in a couple of days (I am travelling on business).

Do not ground the tank to the boat. A metal hull should never be used as a ground, or as a conductor. This will result in serious stray current corrosion on your boat, and if in the water at a marina, to boats around it.

On outboard powered boats the ground is typically the engine block grounded through the engines wire harnesses. But if no ground exists through the wire harness you can ground it by connecting to the battery negative, but better practice is to not go direct to the negative on the battery. Install a negative buss bar, with one wire from the Buss to the negative. Then all negative wires should be connected to the buss.

Do you really need an anti-siphon valve? An anti-siphon valve is only required when fuel can auto siphon into the engine, and that only happens when the fuel pickup on the tank is higher than the fuel inlet on the engine, unlikely on an outboard powered boat. Anti-siphon valves are notorious for clogging so if you don't need one don't install one. Plus that, eliminating that fitting eliminates two sources of fuel leaking. Most leaks are from fittings. Fewer fittings means fewer potential leaks.

18 gallons of gas weighs about 110 lbs. two 6 gallon tanks full, weighs about 75 lbs. So you are going to have more weight aft which will make the rear sit a little lower. You may want to shift something forward to compensate which will help the boat get on plane and run flatter. Anyway think about it.

I will let you know if I think of any thing else.

Hi Peter;

Thanks for the input. One thing, however, is that my 73 is a fiberglass hull.

I can run the tank ground to the negative buss bar, but that adds about 10' of wire. Why is this better (does it prevent ground loops, or something else)?


Thanks

Do I need a ground plateon hull of boat, too (or is outboard motor enough ground)?

The few boats I've run across that originally came with a fixed inside fuel tank had them, with the ground wire running back to (the tank ?) if I'm not mistaken. I think I would put one on the boat, just for safe measure. Just my two cents.......

I would consider putting a tank in front for balance reasons. Your setup might tolerate rearward weight bias better than my rig though. I think my motor is a bit big in back, so moving the fuel cell up front really helped with ride and speed in my glasspars case. Was using rear mounted gas tank as well,, no more.

Also... If its like other old boats and motors, then youve got a primer bulb to get the fuel into the carb.. Its much easier to lean over, from the capitains chair, prime the motor, and fire it. With rear tank,, you gotta scamper back and forth if it takes several tries to prime and fire the beast. my .02

Welcome to the "gettin' too old to lift those %$#&*(()(*^ tanks club
I installed a 12 gallon steel tank two years ago on my 17' shell lake and now planning on installing an 18 gallon plastic tank instead. Dogone '61 V4's suck a lot of gas! The steel tank is grounded to the engine ground through the wire harness this was easier because all the wire connections will be under your dash, the fuel sender/gauge need to be grounded also.
Only problem I have is adding the oil when filling. You have to make sure to keep the proper mix/ratio without overfilling. I usually keep track of how many gallons pumped and then add the right amount of oil.

Thanks all for your thoughts.

As for ratio, I have tested the accuracy of the gauge, so I think I will be able to estimate the gas needed, and thus the amount of oil to hit 50:1 mix. I will go conservative to be safe, so always room for enough oil.

As to the grounding plate, do I do that AND ground to the negative bus bar? If so, why? Doesn't the outboard offer the same grounding through the harness (no isolation, as some I/O set ups).

Boat was designed for tanks in rear, and front is open-bow seating arrangement, so no moving the tank forward. I currently go out with three tanks (2 under the splash well plus on in front of them so we can stay for a day or two with no worries), and she planes with no problem and runs very flat (can hit 35 mph).

As to the issue of the squeeze bulb, I have no issues. Motor starts right up so long as pumped till firm. I have never needed to re-pump the bulb, so this will not change anything. I do not run any ethanol fuel, so no worry about phase separation - and I will use stabilizer if any left in it at season's end.

Take some pictures during your install and we can compare notes. I'll do the same. In the process of running the tank empty the next few days , adding guide boards on my trailer and figuring out how to install a power tilt

63Sabre, I have taken some photos.

To get the tank up off the floor, at Lowes I found great recycled tire rubber 1/2" thick, slotted stair treads that I cut to size and attached to tank bottom with JB Weld. No chance of any splashed water sitting under the tank, so no worry of corrosion under the tank (plus no stopping wet bathing suits etc water getting to the bilge. Once in place, I will add some foam above to sandwich it in place (to replace the foam under the splash-well that I removed to make room for the new tank, as well). I just need piece of 5/8 marine gas hose and I am ready to do the install.

Here is pic of the rubber step tread header from Lowes:



This should work great - channeled to run water away. Here are some pics of the install on tank bottom:

I flipped some of the pics to make easier to orient.....

More pics - here is tank area under splash well. Notice I had to remove a bunch of flotation foam. The original Evinrude OMC tanks are still sitting there (not removing until the install day).







The original snap-down flap will hide everything nicely.



I will screw the tank down by the aluminum mounting tabs, using stainless screws (sealed with silicone). With it screwed in place, plus a bit of foam on top to snug it in (I will only use enough to hold it in place, but keep it away from the sender, hoses, and wires for easy maintenance).

Here are a few more pics for now:



Here is where the filler/vent combo will be installed.





Here is another pic of the sender. This sender could not be any easier to install. White wire to the gauge sensor post, black wire to the boats ground. As I said earlier, a green 10 gauge ground wire will run from the tank ground to the ground bus bar.

interesting thread, i too am in the need of a large tank under my splashwell i measured the space then got the volume calculator and i figured i could get 38 gallons under mine. i thought about the front tank but i did not want fumes in my cabin. under my bunks and that long hose running the side of the boat i have two batteries and my tilt trim pump back there i thought of saddle tanks but again i would need a holding tank that both tanks fed into to supply the motor and then fuel pumps and relays and all that. no a simple tank near the motor and a fuel pump weight will be a factor i need to weigh my cabin pieces and see what is up front and what is in back. but back to this idea.... i want to see a photo set as well ..

billy

Installed filler on boat this evening, without much trouble (biggest issue was removing foam from the area beneath and cleaning up the subsequent mess).

Found that the filler hose would not allow for the necessary bend needed to hook it up (the hose could not do it without kinking... So, back to the welder we went. I m having the filler tube fitting on the tank moved to an area directly under the filler assembly installed on the boat (and welding shut the hole created by removing it from its current location. I will pick it back up on Monday afternoon, so no working on it this weekend....

So close, and always another problem. Thank goodness I got the tank for only $50.00 on Craigslist, so another $35.00 for Aluminum welding is not that big a deal. Had I paid $300.00 for the tank it would be a different story.

pics of the progress

Here is the placement of the new filler. Although a stainless or chrome cover would probably be more appropriate, I had budget and location to worry about. By doing a combo filler and vent, it saves space and reduces the chance of spills.

Here is pic of tank with ground wires and sender wire attached. The bolt, washer, and nut are 316 stainless, to prevent corrosion. All exposed parts coated with dielectric grease.



Note: since the cleat is relatively close to the filler, I have run a ground wire from underneath the cleat that will attach to the ground on the tank, so no worry about static spark (just to be extra safe). To do this I removed the cleat, put a wire fitting to one of the screws, and drilled a hole under the cleat to run the wire down to the tank area, Once the cleat was replaced, cannot tell it was done.

Here is pics of wiring, tank label, etc.







Sorry if over-doing the pics...

Tomorrow I will move some wiring behind the dash so I can drill for the fuel gauge (will need to relocate the negative bus bar, and lengthen some wires, to make enough room. Will post pics of the progress. New gauges are Faria Euro White series (speedometer, fuel, head temp, and tachometer).

Looks like excellent work Crestliner, very nice indeed.

Excellent it looks GREAT!!!!

Bob

Thanks guys. If it were not for needing to move the filler on the tank I would be done and back on the water. At least it is a rainy day, so easier to stay in. Going out to the garage to work on the dash now.

Well, as things would have it, I got my tank back from the welder....
pressure tested it and found 2 pin leaks.

One pinhole leak is in the weld to close off the old filler neck. My daughter saw it and said "it's gonna leak here" before we even tested it. I really thought she was wrong until it bubbled up at 3 psi with soapy water....

The other leak is on the new filler neck - in a spot that was not welded - hard to believe a new "bad" piece of aluminum pipe.... I watched them remove the plastic wrap from new pipe.

So, off to the welder again in the morning - Darn it anyways!!!!

Wish me luck.

Got the tank back from the re-welding - pressure tests good now (no leaks at 4 PSI). Yippeeeeeeee!

Here are some photos of it now:



They decided to cap off the original filler, rather than cut it off and plate over it (said they were worried about too many filings getting into the tank). The cap is 1/4" aluminum, so should be strong as an ox.





Here is it in its space - ready to connect up.

Here are more pics of the install. Ground wire from the cleat now connected to tank ground tab - other end of tank ground 10 gauge wire to soon be connected to the ground bus bar.





And here the filler and vent hoses are installed. Double clamped on each with 1/4" gap between the clamps, as required.



Closer look:

Tank has been screwed to the deck with stainless screws, so it cannot move a bit. Every screw was sealed with silicone, so no water can penetrate the floor. I had to notch the floor level snap rail to crear the tank mounting screws - can't tell from the face, so looks like it was meant to be. When I had the aluminum snap rail off, I found they never put sealant around the screws that go into the deck. I added silicone sealant to them before re-installing, so better than ever.

I still plan to replace a bit of foam, which will sandwich it down even more (top side only).



Here is filler permanently installed - it has silicone under all screws and edges, so spills cannot leak into boat or bilge.





Rear snap down cover clears the tank perfectly.



Next project is mounting the gauge and re-wiring the dash to clean things up. I needed to relocate the bus bar to make space for the fuel gauge.

Excellent!


Bob

very nice... im in the middle of a new tank install myself... waiting on my tank to come back from the welded now.. i also had to move my filler neck... but i had to cut the old filler neck off.. and plating over it...

very nice... im in the middle of a new tank install myself... waiting on my tank to come back from the welded now.. i also had to move my filler neck... but i had to cut the old filler neck off.. and plating over it...

Thanks Bob. I will get the dash work done this weekend. Hole for gauge is drilled and neg bus bar removed for relocation and wire organization. Almost there.

Vintagerunner: Be sure to pressure test - you don't want to blow up. Even a perfect looking weld can be a leaker, as I have found.

Well, the project is completed. Fuel tank fully installed, gauge installed, all wiring completed, and gas in the tank. It feels good to finish a task - but what will I do next? Will have to find something else to obsess over. It should warm up this weekend (we have been cool/cold and rainy for the last 10 days in the Carolinas. Nice to see the rain finally stop. I am in the Charlotte area (25 miles east)and so did not get hit as bad as they did in SC. 24" of rain fell on Columbia SC.

The lakes around here will be high water level, as they are holding water back to give SC a break. The rivers around here are over their banks and full of muddy water (that red clay makes a mess).

I will take some final pics of the project and post soon.

Kudos on a safe and neat installation, I can,t see where the fuel line runs after it leaves the tank but make sure it is not allowed too rub on the edge of the tank.

Fuel line is held up in place behind where the rear cover flap hangs, going over to the squeeze bulb and then out to the motor. The photos were taken before that was done. I also still have to spray a bit of foam above the tank to replace the flotation foam that I removed.

Here are the final photos -

Here is how the fuel line is supported across back of boat - out of the way and safe and secure. More than enough slack for turning to steer.



Here is view of it going across






foam has been sprayed (still to expand a bit more and harden in place.

Here are photos with the foam sprayed and expanding:



And here is a closer shot - new foam is a lot brighter than 43 year old foam.



Here are pics of the gauge installation. I would have preferred a different spacing, but I had to work with existin holes and hidden structure.



view from the side:



View of trim back in place, notched to allow for the tank mounting bracket that is siliconed and screwed into the deck.

Sorry, I didn't mean to leave you hanging but I had a busy two weeks. It looks like you did an excellent and safe installation. I know you pressure tested the tank (very good!) but have you pressure tested the system with everything hooked up? And 3 psi is all you need. Going above that is not really necessary.

Also glad to see you replaced the foam. I do worry though about the areas where the foam contacts the tank. Moisture could be trapped between the foam and the tank, but if you make sure it all stays dry it shouldn't be a problem.

Good job, and good example for others to follow.

Hi Peter;

Yes, we did pressure test entire fuel system after installation. Held 3 PSI for 1/2 hour, so I am confident we are good. I wanted to be sure before I felt safe to put it back in the garage with fuel in the tank.

As to the foam, I only put above tank where it was removed. This area should stay dry at all times. The base of the tank is elevated with room to dry out should water be on the deck.

I really appreciated the input - I learned a lot doing this install (I will not miss lifting those 6 gallon tanks...). The good thing is I gained a bit of storage space in the rear, as the new tank design is more efficient space-wise. Thanks again!

Found a 10 micron water-separator/fuel filter on Craigslist (NEW cartridge still in plastic wrapper) for $20.00 - couldn't pass that deal up.

I just installed it - was not too difficult. Tested and all good.

I ran the fuel line so it does not rub on anything. The squeeze bulb is in an easy to get to location, as is the drain on the filter.

Here is what it looks like done ... all hidden from view.





Thanks again, all.

That Racor is a good unit, you shouldn't have to worry about dirty fuel or water problems anymore!

Good move. A problem I've found with the fuel/water separators (and I use them all the time) is that if they are mounted above the fuel source there is a tendency for the system to get air bound. When you pump your bulb the initial time it takes forever. If you have even the slightest leak, even when you disconnect from your motor air gets in the line. Elimination of the problem is to mount the filter on the same level as the tank or even below. Just sayin'. If you have a situation, simply change the mounting position of the filter.
Good luck.
Cal

Wow nice price!!!!

Bob