My primer bulb stays collapsed once I get on plane.

[kbmsound]

Ok, I am stumped with this one folks. My yamaha C115tlrx gets on plane and after a couple of minutes the motor seems to bog down and loose power. Here is why I am stumped. Compression is good, carbs are recently rebuild, fuel lines from tank to motor are brand new marine lines, brand new anti-siphon valve at tank, which is a separate question I have, will PS below. Brand new fuel pump, pick up tube was a bit kinked but I straighten it out, screen was clean, full gas tank with rec 90, and oil. Brand new gas tank vent, I can hear and feel plenty of air coming out when fueling. Sometimes it runs great, others it has the issue. I tried running with the fill cap loose to make sure the tank was venting. Still did it. It's not overheating, and got strong pissing. The water separator was a bit corroded inside but to debris came out when I drained it. Getting new one tomorrow. The only thing I have left to replace is the quick connect at the engine, which started to leak when I primed it, but that only started after i got home and flushed it and messed with it to try and find the culprit. In the water today it did not leak at all. Anyone have anything else I may be missing? Thanks.

P.S. When I replaced the anti-siphon valve, the old fitting was completely hollow, no ball inside. My question, do some boats have the anti-siphon with the ball inside, and some don't, or do all boats have that? I was told that without it gas would return to the tank after planing off.

 

[jimmbo]

If the primer bulb is collapsing, it would mean that there is a restriction upstream of it, or perhaps the bulb is installed backwards or the check valves in the bulb are backward. Anti-siphon valves are not normally used on outboards, but they often jam shut. The one on my boat was jammed shut from the factory, the ball is now resting on Davy Jones's Locker. Normally I would suspect the tank isn't venting, but you say it is clear and have run with a loose cap. A clogged water seperator, if upstream of the bulb would cause a collapsed bulb. The "kinked line" could still be restricting flow if internal damage is there

 

[kbmsound]

If the primer bulb is collapsing, it would mean that there is a restriction upstream of it, or perhaps the bulb is installed backwards or the check valves in the bulb are backward. Anti-siphon valves are not normally used on outboards, but they often jam shut. The one on my boat was jammed shut from the factory, the ball is now resting on Davy Jones's Locker. Normally I would suspect the tank isn't venting, but you say it is clear and have run with a loose cap. A clogged water seperator, if upstream of the bulb would cause a collapsed bulb. The "kinked line" could still be restricting flow if internal damage is there

Jimbo, I took apart the base of the water separator, as well as the filter itself and while it was a bit dirty, it wasn't clogged. The kink in the pick up tube in the tank I fixed. All the lines are new all the way to the carbs. I will buy a new quick disconnect, water separator, and primer bulb tomorrow. Will update as I will take the boat out again tomorrow.

 

[QBhoy]

Defo a sign of the primer bulb being back to front.