Randomly collapsing primer bulb?

[unaball3r]

Recently bought a 94 Renken 1780cc with a 93 Yamaha 55. I am having a heck of a time with this primer collapsing and killing the engine. I finally got to see it happen today after about 20 minutes of cruising. It just randomly collapses all at once. It's not a gradual incident. I can't make it happen either. I have tried aiming for choppy water, running wot, dropping to 1/3 throttle, cruising at different speeds. Nothing I do has replicated it other than enough time on the water. And time is random. Sometimes 5 minutes, sometimes 30, sometimes 15 etc etc. I am thinking I have trash in the tank that happens to get it's way to the pick up tube and block it randomly. As if I sit for a little bit after the bulb collapses it goes back to working normal then it's back to rolling the dice to see how long it will run before the bulb collapses. Lol. Replaced the bulb and everything engine side is fresh. Still haven't replaced water separator or drained tank. Oh and removing the fuel cap while bulb is collapsed does nothing. My vent didn't seem to be blocked because I can blow into it freely and get the distinct smell of gas. Sorry for the book. What do y'all think? They motor runs fantastic while it's actually running lol.

 

[99yam40]

something is restricting the flow of fuel from the tank.
is it a built in tank?
if so, it should have a anti syphon valve and or a sock/filter on the pickup tube that needs to be checked on

 

[unaball3r]

It is a built In tank. I may pull the pick up and take a peak at it. Not even sure if my boat has an anti syphon valve.

 

[brodmann]

I would start by replacing the fuel/water separator. That is also a filter that might have trash in it or be clogged somehow. That's a pretty easy $20 possible fix. A quick test would be to buy a barbed fitting and take the hoses off of the fuel/water separator and use the barbed fitting and hose clamps to bypass the fuel/water separator and see if that solves the problem. I had a fuel delivery problem out in the water and fortunately had a long enough hose with some slack in it to disconnect the hose from the separator and hook it directly to my primer bulb and it took care of the problem.

 

[99yam40]

I would start by replacing the fuel/water separator. That is also a filter that might have trash in it or be clogged somehow. That's a pretty easy $20 possible fix. A quick test would be to buy a barbed fitting and take the hoses off of the fuel/water separator and use the barbed fitting and hose clamps to bypass the fuel/water separator and see if that solves the problem. I had a fuel delivery problem out in the water and fortunately had a long enough hose with some slack in it to disconnect the hose from the separator and hook it directly to my primer bulb and it took care of the problem.

but if there is water and trash in the tank you will trash up the rest of the system if you bypass the filter, if it was a plugging filter

 

[QBhoy]

Hi. Most commonly this is caused by one of a couple of things.
The vent on the tank blocked
The primer bulb and fuel line is on the wrong way about (they are uni directional)
The fuel line and/or tank pick up is getting blocked at its source
The fuel filter (if fitted) is blocked
The non return valve on the fuel line/primer bulb is blocking.

 

[brodmann]

9, My recommendation for the guy was purely for diagnosing the problem. I never intended to suggest that he take the fuel/water separator off and throw it away. That's certainly not what I did on my boat. I was just trying to help him figure out what was causing the problem. I suggested that he replace the filter. I then gave him a way to test to see if that was the problem. Never intended the bypass as a permanent solution to the problem.

 

[KJM]

I'd start with the fuel/water separator. I recently was stranded on the water because of a clogged filter. No water, just a clogged filter. Also, as suggested, the bulb could be on backwards.