Fuel Problems??

shana · #1 10-12-2009, 07:51 PM

Hi All,
I just purchased a 1975 20' Seafari Seacraft and I'm running into some problems. Hope you guys can help a newbie out...Well, it runs fine, then when you throttle up it bogs down and shuts off...We think that we're not getting enough fuel to the engine. Here's what we did so far. We drained the tank and replaced the old gas (some water was in it). Then we drained the Mercury (engine) carbs. We replaced the fuel filter and blew the lines out. Still happens. We notice that when we pump the fuel primer ball that it works better, but then the ball becomes flat and we cant pump it any longer. We then took the cover off the fuel tank area and blew out the vent. Then we thought that there may be a clog in the line in the tank, but when we took the 90 degree thingie off, we expected to see a hose, but found a metal tube which went from the top of the opening to the bottom of the tank. We could not figure out how to get the metal tube out and we were surprised that it wasn't a rubber tube with a screen on the end. Please Help!!! Any Suggestion would be appreciated

BigLew · #2 10-12-2009, 08:28 PM

Did you blow out the air vent line to the tank? Did you blow the ENTIRE fuel line Back towards the tank with the line detached from the tank? How old is the fuel line bulb and could the check valves be hanging up?

You are apparrently are not getting flow from the tank to the engine despite the engine's fuel pump pulling what fuel is available (the collapsed bulb.) be sure to blow the lines out in reverse flow fashion and replace any suspicious compnents. (I would be particularly suspicious fo the vent line because insects have been known to get into them and build some sort of nest/obstruction.) If it were me, regardless of what I believe I found, I would likely replace the bulb and their check valves in addition to any other components I suspected.

Just my 2 cents.

Old'sCool · #3 10-12-2009, 08:42 PM

And all the hoses/lines...

rockdoc · #4 10-12-2009, 09:54 PM

try running it off a 6 gal tank just to rule out engine carbs fuel pump etc

Steve

Bushwacker · #5 10-13-2009, 12:13 AM

Quote:

. . . We notice that when we pump the fuel primer ball that it works better, but then the ball becomes flat and we cant pump it any longer. We then took the cover off the fuel tank area and blew out the vent. Then we thought that there may be a clog in the line in the tank, but when we took the 90 degree thingie off, we expected to see a hose, but found a metal tube which went from the top of the opening to the bottom of the tank. We could not figure out how to get the metal tube out and we were surprised that it wasn't a rubber tube with a screen on the end. Please Help!!! Any Suggestion would be appreciated

When primer bulb stays flat, you most likely have some restriction between the bulb and intake in the tank, but I'd run it on a 6 gal tank first to isolate problem area. Need to be careful with fuel starvation problems if you're running pre-mix, because you're also starving the motor of oil!!

If it's a vent hose problem, just take filler cap off to see if that helps. If your tank is original like mine, I believe that metal tube, which is probably welded to the tank, goes down to about 1/8" or less above tank bottom. May or may not be a screen or gravel strainer over it. Also check that 90 degree fitting while you have it off to see how big the inside flow area. I have heard of restrictive fuel tank elbows causing fuel/oil starvation and blown power heads!

It's not that hard to pull the tank on a Seafari and I'd suggest you do that just to inspect it to make sure you don't have any other tank problems waiting to bite you after you solve the fuel restriction issue! Did it when I first got mine, and found that someone had dropped brass nut down into tank compartment before they installed the tank, so the aluminum tank was sitting on brass nut! That creates a great galvanic couple wherein the aluminum tank is the sacrificial anode to the brass nut! This means the tank will dissolve to protect the nut, much like the zinc trim tab on your motor will dissolve to protect the lower unit! Fortunately I caught it before it ate thru the tank. Coat that tank with coal tar epoxy while you have it out, and it'll last the life of the boat!

Welcome to the Seafari club! Let us know what you find out!
Denny

BigLew · #6 10-13-2009, 12:25 AM

Man I love this site. So much experience and the price of it all is to just contribute what we know and sit back and find out so many things we've yet to encounter AND their solutions before it happens to us. WOW!!!