little help with a fuel problem..

[aqua719]

I have an 1980 osprey that i've had and been workin on.
Been running strong, but last time out, at about half throttle it would bog down starving for fuel. checked to find the primer ball would only stay half full all the time. Replaced ball-same thing. replaced water seperator-same thing. replaced line from seperater under console back to primer ball.- same thing...  
My next thing is to pull the console off to get to the tank. the original tank was replaced +-4 yrs ago with a 36 gal aluminum one by the previous owner and have had no problems, but could it be the line, connections or sending unit??  Not sure if those were replaced. I'm good at doing odds and ends but have never opened it up before. Any tips or thoughts would be appreciated! Thanks

[fitz73222]

Hey Aqua,
It could be a clogged vent that will not allow the fuel to draw. Try running it with fuel fill cap off or very loose and see if it runs better. If it does, look and see if the fuel vent is clogged with debris,bugs. etc. It can also be a kinked or degraded vent hose in need of replacement. Lastly, the fuel line is plugged between the tank and the engine. Take off the primer bulb and blow through the line and see if thats the problem.

[dirtwheelsfl]

Check to see if its got an anti-siphon fitting on the top o the tank.  If it does, then try replacing it with a regular barb fitting. Id put my money on that being the culprit...

[Georgie]

The fact that the bulb won't pressurize fully sure does makes it sound like a fuel delivery issue.  Did the issue slowly get worse to the point where it is now, or did she just all of a sudden not like anything above half throttle?  Since you've replaced your whole line from tank to bulb, it's probably fair to assume you don't have a cracked hose/air leak. I'd guess tank vent, tank pickup, or anti-siphon valve first (given the parts you've already replaced).  Can't be the sending unit as it has nothing to do with fuel delivery.  Have you checked your tank vent located on hullside near fill hose to see if it's visibly clogged?

[Blue Agave]

Hey Aqua,
It could be a clogged vent that will not allow the fuel to draw. Try running it with fuel fill cap off or very loose and see if it runs better. If it does, look and see if the fuel vent is clogged with debris,bugs. etc. It can also be a kinked or degraded vent hose in need of replacement. Lastly, the fuel line is plugged between the tank and the engine. Take off the primer bulb and blow through the line and see if thats the problem.

X2 on the vent.

[aqua719]

Thanks for the great info!!  didn't think of the vent.  Going to check that this weekend, as well as pull off the console and check the fittings and hoses as mentioned to see if anything needs repairing or replacing

didn't notice the problem getting worse, just that the ball wouldn't stay full of gas when I took her out.

[GoneFission]

Here's an often overlooked problem - check the clamps on the fuel lines.  An oversize or loose clamp will allow air to enter the line - and both the bulb and the fuel pump will suck air before fuel.  I've seen cases where the wrong size clamp would not fully seal the hose on the barb and allowed air to be sucked in.  In other cases, the clamp was not tight on the fuel line.  Do you have a pie plate opening that allows access to the fittings?

[Capt Matt]

anti syphon valve would be my guess too
Capt Matt

[CTsalt12]

Before you pull the deck up, check the vent from the outside first!  Could save you many hours of work.  Check the screens, if you're missing one it probably got sucked in and is clogging the vent!  Happened to me this summer

[aqua719]

Vent is clear. This is what I found when I opened her up.  Doesn't look like it has the anti siphon valve.  After really cleaning it up, found that hose clamps were not tightened enough and had one spot of line that was ate up.   cleaned up and replaced/repaired the fuel guage wires and all hoses and clamps, etc.  Hooked it back up and seems to be running good.  Going to water test later this week.    :santa:

[seabob4]

Aqua,
Hope all goes well this weekend, but I would seriously be looking at replacing that pickup...

[CLM65]

Aqua, I hope you have solved your problem.

If not, when you say the bulb is not getting hard, is that when the engine is running or off?  You may not be able to get the bulb hard while the engine is running, especially if you are checking it when it seems like it is fuel-starved.  When the engine is off, pumping the bulb fills the bowls of the carbs (I'm assuming your engine has carbs).  That raises the float, which closes the float valves.  With nowhere for the fuel to go, the bulb gets hard.  When the engine is running, you are adding fuel to the carbs, but it is also being fed from the carbs to the engine, so you areally just helping replenish what is being consumed.  Unless you can fill the bowls quicker than the fuel is being used, the bulb will stay relatively soft.

If you find that the problem still exists, I recommend you get a portable tank and hook it up as close to the engine as possible (make sure you add oil if you pre-mix).  This will rule out anything in the fuel line/tank/vent.

Again, I hope you have fixed your problem, but if you haven't, using a portable tank will allow you to rule out several possible problems.  Good luck!