V21 Fuel Tank Removal - questions

[13Echo70271]

Hi Blue,
The fill vent could be a problem, but if you have checked it already,
Does one or both of your round inspection ports/hatches access the fuel sending unit, fill hose and vent hose connections to the tank? In destroyers pics they are all on one end of the tank. My 88 has a plastic tank and the sending unit and fill hoses are at opposite ends of the tank.
I think if I could access them, I would check those fill hoses for rubber crud inside,
Tipp the boat so the sending unit is at the low end, drain the tank, using the boats fuel line or a siphon hose. If you can, use up most of the fuel first.
remove the sending unit and using the sending units opening in the tank inspect and remove any debris. Any debris left could be swabbed out with a small rag tied onto a stick through the sending unit opening. You may find you don't have to remove the tank.
Do NOT use a shop vac to remove debris, as fumes drawn into the vac can ignite(ask me how I know).
If you have to open it up bigger, I would consider cutting two 14" x 14" or so, openings around the current openings for a couple aftermarket floor hatches (ebay). That will give you more working room. Much easier, cheaper, faster with fishing season upon us.
Best of luck,
Tom (13Echo70271)

[Destroyer]

I used a combination of tools to cut the deck. As you can see in the pics several places I went further than the corners with the cuts. Those cuts were made using a circular saw. Then I wised up and started using my multi-tool (http://www.harborfreight.com/power-t...ool-61219.html) to make the cuts into the corners. Much neater without the overcut of using just my circular saw for the cutting.

Yes, the middle round hatch is right over the fuel tank sending unit. Not really sure how much room you would have with them removed or out of the way, but it's not a bad idea to empty the tank as much as possible, remove the fuel lines and sending unit and try with a HAND pump to suck out whatever debris may be in the tank. Orientate the boat so that it's slopping towards the bow so any debris will naturally flow/move towards the pick up sending unit holes.

Finally, are you SURE that your vent line is clear? An insect or something could built a nest in there. I recall somebody in these forums a few years back had a similar problem with their ball collapsing and it turned out to be a mud wasp nest in the vent line. Take a electricians snake and run if from the tank to the vent cover and make sure it's clear before you go into something deeper. K.I.S.S. it first.

[phatdaddy]

Also Blue, where u cut, there will be raw wood. That will have to be sealed

[mawshj]

I do not know if you have the same valve where the hose to the engine hooks to the tank, but on my v20 (1983) that valve is a problem, the screen in it will fill with small (sand size) junk and a slight blow back will clean it. I removed all gas and sopped up all I could with rags thru gauge hole several times. finally got it cleaned up. ok now

[Blue_Runner]

I'm 99.9% sure it is not the vent because when it happens and I blow the fuel line back into the tank I can feel the obstruction and can feel it blow back into the tank.

I pumped the tank but did not do the swabbing with a rag on a stick. I did find some sand sized black specs presumably old fuel line particles but don't see how those would not make their way to the h2o sep and or inline filter?

I did remove the pickup and elbow - it is not anti-siphon. There is no screen on the end of the pickup. Pickup is like a piece of fuel line that lays on the bottom of the tank. Notice the pickup is on the front of the tank - it has to lay on the bottom of the tank to reach the back. When I took it out the pickup had a coiled up spring inside of it. I figured the spring was to 1) serve as a screen to block large debris and 2) keep the pickup from collapsing. I took it out but could not get it back in. The pickup seems rigid enough not to collapse and surely could not have collapsed with the spring inside....unless it was collapsing above the spring near the elbow.

I've been a whole season without this happening before. I have had it happen 3 times in a season. I've had it happen when the tank is full or near empty. I change my fuel water separator once per year and it seems to want to happen more when the fuel water separator is near needing replacement. However it was just replaced so there goes that theory.

We rode all the way out on Saturday 65 miles and it did not happen. Trolled all day and did not happen, then it happened on the way back to the hill and the weather had unexpectedly turned to sh!t - bad timing.

Thanks fellas. I really don't know what to do!

[Destroyer]

Originally Posted by Blue_Runner

I'm 99.9% sure it is not the vent because when it happens and I blow the fuel line back into the tank I can feel the obstruction and can feel it blow back into the tank.

Well, you can feel the obstruction move and stop blocking the air or fuel flow. But truthfully you cannot feel it blow back into the tank, you can just feel it move enough to clear the flow. If it's in your vent line and right near the top the vent cover could hold it in place enough so it wouldn't blow out and over time it could get sucked back in again. I realize we're grasping at straws here, but I'd make 100% sure it wasn't the vent line before I started pulling and cutting stuff apart.

[SkunkBoat]

I'm not familiar with that setup. Mine has a pickup in the stern end of tank. It is a hard plastic tube reaching just short of the bottom of tank.

Your tube lays on the bottom of tank reaching all the way to the back? There are no baffles in the tank? Could the tube be sucking up against a wall randomly?

I know you can't test it because it is intermittent but if it were happening, opening the fuel filler cap would rule out the vent...with a big sucking sound...

you said the primer ball sucks in... like a deflated football? Brady-Belichek syndrome...move to New England, it will be fine....

[Destroyer]

Originally Posted by Blue_Runner

I did remove the pickup and elbow - it is not anti-siphon. There is no screen on the end of the pickup. Pickup is like a piece of fuel line that lays on the bottom of the tank. Notice the pickup is on the front of the tank - it has to lay on the bottom of the tank to reach the back. When I took it out the pickup had a coiled up spring inside of it. I figured the spring was to 1) serve as a screen to block large debris and 2) keep the pickup from collapsing. I took it out but could not get it back in. The pickup seems rigid enough not to collapse and surely could not have collapsed with the spring inside....unless it was collapsing above the spring near the elbow.

Can you buy something like one of those trash pump suction hose strainers that screens out large debris? Something like this: http://www.ebay.com/itm/1-1-2-Steel-...YAAOSwll1Wz0AB Seems to me that even if one side gets blocked with whatever, the rest will still let gas flow. Kinda like the small filters they put on the ends of fuel lines lying inside the tanks in 2 cycle chain saws, weed eaters etc.

[phatdaddy]

sounds like the little spring is important.