SF18 factory 47 gallon fuel tank filling problem

[CaptSeaCraft]

I have to pull the sender out of my SF18 to fill her up.When I try from the gas fill it takesabout 1/3 a gallon then dumps out the breather.Upon reading up on this year model I became aware that this is a larger tank than normal and maybe there is a kink in the filler hose causing the blockage.Does anyone have any info on what I need to do o solve this problem?here's a picture of the foil label that is off the top o the tank.I am happy with the larger capacity.....it would seem that since it was a Ranger boat for most of its life that they must have requested the larger tank and stainless railing etc. when they ordered it.In some ways I feel fortunate for the extras.It would be nice to fill it up regular style though...LOL
Any help would be appreciated.
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[McGillicuddy]

Hey Capt. cool name,
Either someone secretly filled your tank or you need to inspect all three gas veins. Obviously the fill should be the biggest hose. It should have a fairly straight path down the gunwale across the deck to the tank. I'd stick a long, smaller diameter hose in it at the fill tube and see if it has any trouble reaching the gas tank (you know, like when you're trying to get some gas out of your Uncle's truck ). There may be a loop in the fill hose or maybe something got in there, but even so, if it were blocked the fuel would likely back up and flood at the fill hole.

The vent elbow is probably next to the fill elbow, and its hose will run toward the vent - it could have a clog that creates an airlock where maybe a pocket of air is just pushing a bit of trapped gasoline out, or maybe there is just some gas sitting in a low spot that is forced out when any comes in thru the fill. Or maybe a chunk of sealant dissolved or broke free and floated into the vent tube. You might start by disconnecting the vent hose at the tank and see what drains out when you force air back down it from the vent. Have a jug ready to catch the gasoline or whatever. And "no smoking" around you...

Obviously, this could happen on the supply hose between the tank and engine, especially at brass elbows. Check your fuel/water separator to see if you find any crap in there.

Sealants for sending units have changed in chemistry over the years as has fuel. I found chunks of silicone were clogging my fuel lines. Someone probably replaced a sending unit and used silicone for a gasket, and modern gas with ethanol probably broke it down causing me grief. Here is a pic of that:


Look into it now before the fishing really goes off.
Good luck and let us know what you find...

[76Red18]

When i first got mine it would only hold about 25 gallons (37 gallon tank I was told). I finally found out the tank was backwards ;vent and fill were at the rear. The hitch on my truck was set high for my other trailers and therefore held the boat at an angle when fueling up. Pump would shut off but gauge would only read 3/4. I think I was also dumping fuel out the vent on quick accelerations; Not good! Sorry Mother Nature. Pulled the tank, turned it around and it solved the problem. Fill and vent up front, sending unit a third of the way from the back. Since then, I've done away with that tank and shoehorned in a 60 gallon set up the same way.

[SeaPlusPlus]

When i first got mine it would only hold about 25 gallons (37 gallon tank I was told). I finally found out the tank was backwards ;vent and fill were at the rear. The hitch on my truck was set high for my other trailers and therefore held the boat at an angle when fueling up. Pump would shut off but gauge would only read 3/4. I think I was also dumping fuel out the vent on quick accelerations; Not good! Sorry Mother Nature. Pulled the tank, turned it around and it solved the problem. Fill and vent up front, sending unit a third of the way from the back. Since then, I've done away with that tank and shoehorned in a 60 gallon set up the same way.

I have the same problem with my tank in my 20. The fill, vent, and pick up are all on the same side of the tank and it is installed with them in the rear. When it sits on my trailer the front end is higher than the back, so the tank rear fills first and creates an air bubble in the tank so it overflows out the vent.

I considered reversing the tank but with the pickup in the front, there would be a point that momentum from being plane would starve my engine of fuel and stall me.

My solution is when I fill up I bring the stand all the way up (its already in that position when I tow anyways) and then me and a bud lift the boat off the hitch and set it on the ground right behind my truck (easy for me as I don't have much tongue weight with that heavy 4s, though enough that I can't get it to budge by myself). This is enough to make the tank slightly lower in the front, so it fills in the front first and properly vents, allowing me to fill up all the way. Afterwords just lift it right back on hitch as its the air pocket that causes it to overflow and not the angle.

Inconvenient? Yes, but an extra 2 minutes work everytime I fill up is better to me than trying to rip out the tank, and then have someone move the pickup to the rear.

[CaptSeaCraft]

Ok....Time to get to the heart of it.
Thanks to my SeaCraft Bretheren for all the great info.I am coming home today to start removing the t-top,and c.c. to get to the fuel tank under the deck.I'll be doing it all myself since none of my so-called buddies have the time to throw in right now.Whatever...I have done it all myself anyway..would someone call my girlfriend to let her know I'll be REALLY Late for dinner and breakfast!LOL
pics to follow.

[SeaPlusPlus]

Good luck! Lookin forward to pics.

[Old'sCool]

The ethanol is known to eat old lines not rated for ethanol.

[deepsushi]

When I replaced the fill hose on my 18 I had the same problem getting it out. There was no retaining clamp on mine but the the fill hose was pinched between the liner and the bulkhead. It was a bitch to get out and I fought with it for hours but eventually it did come out. I think I lubed mine up with some dish soap to help get it to move.

The hose takes a "S" shaped path and the bends are short so the hose gets bound up in the available space. It is almost impossible to move the hose once it is installed as it is so stiff due to the reinforcing wire.

I did manage to get mine back in and I successfully reconnected the fill without having to cut any extra access holes. It would have been a lot faster to cut a hole and add a pie plate but I did not want to go that route.

It was a about a 30 pack job -- and a half box of band aids to cover up the scrapes and cuts on my forearms and knuckles. Good luck - its definately not a fun project...

[makade]

I have a pie plate adjacent to the fill. It came in handy a couple of weeks ago as I replaced my vent fitting, I honestly think that was the last piece of 33 year old hardware left. I had thought of installing speakers up forward where the pie plate is, but I need a stereo first. When I did my hoses i had the tank out so I had a real good pull alignment wise. Its absolutely criminal if they started foaming around the lines post Potter. I got to say I was impressed when I saw the duct glassed into/under the floor that the hoses route threw. That could be a detail that was lost after the early years?

I did notice that my original 30 gallon tank was placed in the rear of the tank well, and the remainder of the space forward was filled with foam. Maybe when they switched to the bigger 47 gallon tanks they started adding foam forward of the molded in tank well?

[CaptSeaCraft]

Holy Cow.....They never tought the filler hose was gonna need to be changed!Finaly it came out..at 8:00 this morning...(i started at 6:30)and yes I was a little late to work,LOL.Sadly I did have to drill a small access hole,there was no other way,Then I actually had to dig it out of the foam and cut it in half behind the acces hole to get it to budge.the hose was massacered....it was in such bad shape no wonder it did not take any fuel! I pulled a new 2 1/2 fill and 5/8 vent along with a new ground when got home today.I stopped there till tomorrow and just spent a hour cleaning up tools and whathaveya'.I must say this was a very tough job.I had no help and was feeling defeated a couple times but persistance and determination will always prevail.I am building a U turn out of brass fittings to correct the kinking issue due to the fill neck facing the stern.I took a few pics as I went.There will be more as I spend the tediouse time of hooking up the hose's,stripping sealant,rewiring,and re-bonding the fuel tank hatch,console,and t-top.Since I am a Glazier,auto/boat glass replacement technition by trade,I will find this kinda fun.Sealing stuff up is what I do.Note the sealant around the docking light.I just changed the bulbs out 2 months ago and rebonded them with uerathane........it was so pretty till last night...LOL.well,gotta go.I will send finishing shots as I go.I plan on being finished on friday.
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