Fuel blockage on seafari

[McGillicuddy]

I think I have something blocking my fuel flow causing my fuel pump to work harder than it can.

I ran about 50 miles last Sunday and ran flawlessly, but when I got back to the kelp beds I put it in idle and we started drifting to fish. After about a minute of idling, the motor would die.

I know the pump creates about twice as much suction at speed than at idle so to some degree that substantiates the ability to run at speed. Switched over to auxiliary tank to run home and idle was fine - in fact I let it idle for 15 minutes at the dock while fetching the trailer.

I've removed the horizontal brass fitting and it doesn't seem to have a check valve. Wondering about the supply elbow on main tank. If I unscrew that what will I find? Is there an anti-siphon valve within that elbow? Or is there crap in the pickup tube? How would I determine that?

[stumpie2]

THERE SHOULD BE AN ANTI-SIPHON VALVE THREADED TO THE ELBOW AND THERE SHOULD ALSO BE A SCREEN ON THE END OF THE PICKUP TUBE. IF ITS NOT ON THE END OF THE TUBE THERE WILL BE A CONE SHAPED SCREEN WHERE THE PICKUP TUBE TREADS ONTO THE ELBOW. DONT FORGET IT MAY ALSO BE A PROBLEM WITH THE VENT TO THAT TANK. JUST MY .02

[McGillicuddy]

Thanks for the feedback nuthinfancy. I was pretty sure it wasn't the vent cause I usually check it for air release when I'm filling up. I removed the fitting at the elbow and put a light in and then a q-tip to feel for a check valve spring and found none. I then removed the elbow and found a blob of what appears to be silicone:


Based on where I found the blue blob any screens are either deteriorated or absent. My guess is that sealant from the fuel sensor broke off or dissolved over the years due to the ethanol gas and each time I top off the tank the ethanol eats away at the silicone or whatever was used as a sealant. Make sense?

[stumpie2]

WELL YOU KNOW THERE ISNT A PROBLEM WITH THE ENGINE OR PLUMBING FROM YOU TANK SELECTOR VALVE CORRECT? IF SO, THE PROBLEM IS ASSOCIATED WITH ONE TANK. THE SILICONE IS PROBABLY CLOGGED IN THE HOSE FROM THE TANK TO THE SELECTOR OR IN THE SELECTOR VALVE NIPPLE. TRY TO BLOW BACK INTO THE TANK THROUGH THE PICKUP TUBE TO BE SURE THERE ISNT ANYMORE "BLUE GOO". OBVIOUSLY IM ASSUMING YOU HAVE TWO BUILT IN TANKS WITH A SELECTOR VALVE AS I DO. ALSO CHECK ALL CONNECTIONS AS YOU MAY BE SUCKING AIR SOMEWHERE. TRASH ALL RUSTED/CORRODED HOSE CLAMPS AND REPLACE WITH STAINLESS. AT LEAST YOU HAVE THE PROBLEM ISOLATED. MAYBE A PIN HOLE IN THE PICKUP TUBE ABOVE THE FUEL LEVEL. JUST THINKING AS I WRITE.

[McGillicuddy]

MAYBE A PIN HOLE IN THE PICKUP TUBE ABOVE THE FUEL LEVEL.

That is an interesting possibility as this has occurred @least twice in the last month as I burned half the projected fuel and the size of the glob is obviously bigger than any logical filtering screen.

How do I get to the pick-up tube, are we talkin' an arthroscopic cam of sorts or wtf?

Clearly there is some flotsam in the tank. Should I just siphon/filter the balance of the tank out, or get a proper fuel polishing service... cost me about 350 clams out here...

[Fr. Frank]

Your Seafari is a 20' like mine. Pull the fuel tank cover out of the floor, and everything is right there, easy access. Remove the fuel feed hose from the fuel pickup fitting on the tank and then remove the fuel fitting, if yours is not a welded fitting. When you remove the fitting, the pickup tube into the tank comes out with it. You can easily see if there's a problem and make any necessary repairs. If your fitting is welded, remove the hose and gently blow high-pressure air down into the tank to blow out any temporary obstruction. Buy new gaskets for the fuel sender, remove the sender and visually inspect the tank. You can also use the sender opening to siphon out any remaining fuel in the tank to inspect for loose debris. If you find loose debris, there are two ways to remove it. One is the terrycloth shop-towel-on-a-wire method, and slowly and carefully swabbing out the whole tank. The other is to remove the tank and wash it out yourself. You can wash out the tank with water and Dawn dish washing detergent. After doing this twice, then blow a hand-held hair dryer into the tank to dry it completely before re-installing the tank.

This is very important: Install all new fuel supply hoses and filters regardless of whether you're re-installing the fuel tank, or just doing a minor clean-up. Don't re-use any old hoses. Consider replacing the vent and fill lines as well.

I put an inline 30 micron particle filter on mine just 6 inches from the pickup. Then my fuel line goes into a 10 micron water-separating Sierra filter with a water drain on it. From there it goes to the fuel bulb and into another (inside the cowling) inline 30 micron particle filter to catch any degraded hose debris.

You can literally do all of this in about 4 hours. The hardest part is removing the fuel tank if it is needed. Bring a cooler on board, and lots of terry shop towels. Better yet, bring a friend who will work for beer and snacks (or Coca Cola). Having somebody to talk with and complain to while working can be a real help.

[DonV]

I'm assuming this is a 3/8" brass street elbow. I'd go back with one just like it, however much newer and prettier!!

[fredbrad]

if 3/8" ,this must be work
https://www.ebay.com/itm/aluminum-3-...3ace%7Ciid%3A1

[NoBones]

Don, It is an aluminum elbow....

I have seen those at Surplus Unlimited in Daytona on ISB (US92)

If you are not in a big hurry I will check for you in the next couple of days.
Only venture out of the woods when it is absolutely necessary..
When you become semi retarded it is hard to get motivated on anything !

Welcome to CSC, you did just fine on your first post with the pic and the
right section..

[Oldboat]

My new tank came with the tube built in it so you only need the 3/8 fitting. They also put two input fittings in I’m thinking maybe they thought I was putting twins on so I plugged the second . Now that it’s there would be good back up if I had issues with the one in use.