A question about fuel pick up and anti siphon

[JWL]

I had my boat in storage for quite a while and took it to the dealer for service. They tuned the engine, drined the old fuel and change the impellor. I picked up yesterday and they assured me it ran fine.

I put it in the water and it cranked and started as it should. After running for about 100 yards it died and would not start again. In trying to restart, I pumped the primer bulb and it would not get hard leading me to believe the primer bulb may be bad. I purchased a new and installed it to no avail.

I suspect it has trash in the pick up or the anti siphon valve is bad. In pulling the inspection plate over the fuel pick up it seems to be welded to the tank. Does it unscrew frome the tank and where is the anti siphon valve located. Exactly what should I check and do at this point besides take it back to the dealer.

I suspect the dealer cranked the engine on a remote tank and it ran only as long as it burned the fuel left in the engine. I say this as they had drained the tank of the old fuel.

Thanks

 

[Phil]

The anti siphon is in the barbed fitting that the hose goes over. The square part is the pickup that you can unscrew. The anti siphon creates a slight restriction to fuel flow and will make it harder to pickup the last few gallons when fuel is low. I have removed mine because of this.

 

[DaleH]

A/S valves = http://classicparker.com/phpBB2/viewtopic.php?t=292

To remove that 'boss' that your fuel line barbed fitting attaches to (that looks to be welded), use (2) box wrenches 180-degrees apart.

Check to see if there is a filter on the end of the fule pickup. If you remove the a/s valve, then also remove any screen on the fuel pickup end ... relying on your Racor fuel/water filter for any contaminent removal.

I did confirm with Racor that it does take a few inches of Mercury of vacuum to 'pull' fuel through their filter element ... as suspected. They stated that 'if' your Racor is mounted in a plane HIGHER than the fuel tank, then if the fuel line was to rupture AFTER the fuel/water separator, then fuel would most likely not be drawn thru the filter and continue to flow.

If, however, any point of your fuel line lies or routes BELOW the level of the top of your fuel tank, then I would keep the anti-siphon valve installed and if doing that, then make sure there is a filter screen on the fuel pickup to prevent crud and lint from clogging the a/s valve.

To me, on OB-powered rigs, it is best to always have the fuel delivery system running UPHILL, from tank to f/w separator and then out of the boat ... then any angle needed to route to the motor.

 

[Sow&Pigs]

This was very similar to the problem I had recently -- the primer bulb was flat and would not draw. The problem was traced back to dirt in the screen at the base of the pickup tube, and a generally gunked-up pick-up tube.

After both screen and tube as well as the entire fuel line were replaced the gas flow was like new.

By the way, contrary to what I had heard on The Hull Truth regarding the Racor and Optimax compatability issue, the 2001 year should NOT have a Racor installed. This from both the head mechanic at a Premier Mercury dealer and from the Mercury factory tech at Mercury.

Hopefully if you change your screen/pick up tube and possibly your fule line you'll get back to normal.

The issue I had was traced back to the "cleaning" action of the ethanol in the gas we have around here.