Primer bulb flat

[Bolo]

HI: I have this problem with my 200 hp yamaha.<br />This are the symptoms:<br />I have a 100 gallon under deck and is bloking fuel flow . <br />Primer bulb gets flat and engine stall.<br />It only happens 1/2 empty .Runs perfect when tank is full<br />I replaced primer bulb , fuel pumps (2) , fuel lines, filters, tank vent, valves, pick up tube .<br />The problem persist. Plase need help

 

[wilde1j]

Re: Primer bulb flat

Does your tank have an anti-syphon valve? It's the first fitting coming out of the tank. If yes, try punching the ball check out (remove first).<br /><br />It's clear you're pulling a vacuum in the fuel line, which is why the ball goes flat. May be something with the vent line routing. How long has this been happening?

 

[Bolo]

Re: Primer bulb flat

HI: THANKS FOR YOUR ADVISE WILDEONE. THE TANK DOES NOT HAVE ANTI-SYPHON VALVE . IT'S CLEAR THE IS PULING A VACUUM IN THE FUEL LINE.<br />THIS IS THE COMPLETE STORY : <br />I GOT THIS BOAT IN JULY 2001 , GOT OUT 3-4 TIMES ( 30 HOURS) BY NOVEMBER THIS HEADACHE STARED .<br />I REPLACED GAS LINES ,VENT LINES , VENT, FUEL PUMPS, FILTERS , FUEL/WATER SEPARATOR,TANK PICK-UP SCREEM , PRIMER BULBS ( 3 TIMES ) WHAT ELSE? EVERYTHING. <br />THE MYSTERY IS , THIS ONLY HAPPENS 1/2 TANK EMPTY , RUNS PERFECT WITH 100 GALLONS (FULL)<br />THIS HEADACHE START ABOUT 6-7 HOURS LATER

 

[Spidybot]

Re: Primer bulb flat

If used fuel is replaced by air as supposed to (and it sounds so from your explanation), the vacuum builds up between the fuel pump and the pickup from the tank. As the fuelpump can do nothing but suck, the problem must sit in the tank. You've replaced the parts, but are you sure it's all assembled and fitted correct? <br /><br />To test the vent try removing the tank cap when the problem occurs.<br /><br />If the problem occurs when tank is half full, it might be something getting in the pickups way (moving parts in the tank should be the tank gauge sender only, but other objects could float around there.. (I once found a piece of hose in a tank - from somebody attempting to steal fuel).<br /><br />If you can, test with another (standard transportable) tank.

 

[Bolo]

Re: Primer bulb flat

I will try thad nex week and i will get back to you

 

[taz33911]

Re: Primer bulb flat

You might want check again on that anti siphon valve it is in the nipple the fuel line is hooked to unscrew the nipple . It has a ball spring and a washer to hold them in.It could be in the fuel fill also could have something blocking the vent or maybe fuel in the vent hose if the fill is the back of the boatfuel can/t run up hill to get out of the hose. trust me it happens I build boats for a living!