primer bulb goes flat at higher RPM

[Crazydays]

Try bypassing separator and go rite to the filter before the LP pump with a different clean tank. This will eliminate that whole list.

[DennisG01]

If conditions permit, run with the cap looser for a longer period of time. Or, just disconnect the fuel line at the canister (the one that comes from the tank). This is just basic plumbing to bypass the canister - you have a fuel line coming from the tank, the mumbo jumbo of the canister stuff, then a fuel line going to the hull vent. Just connect the the two fuel lines together and make sure there is no dip in the line anywhere. The line should progressively go up and, ideally, end with an upward loop at the hull vent.

[zenoahphobic]

Just a thought, could the culprit be the fuel bulb itself?
could it have junk in it and/or the valve in it sticking shut? By pass it.

[JimBen14]

Has anyone bypassed a carbon canister?

[Witt6767]

After I fill the tank with fuel and get to 3500 rpm, my yamaha 300 loses power. It may actually sputter to a stop and take a few minutes to start. I have checked the primer bulb and it is flat. Any advice as to what would cause this?

I would suggest replacing the primer bulb. The rubber deteriorates over time and gets weak. The then normal running negative pressure (Suction) can collapse the primer bulb as the engine is trying to draw fuel.

[JimBen14]

Bulb has been replaced and still happened. Considering following Dennis's recommendation and by passing the canister. I looked on Youtube, but couldn't find anything.

[DennisG01]

Bulb has been replaced and still happened. Considering following Dennis's recommendation and by passing the canister. I looked on Youtube, but couldn't find anything.

I wouldn't overthink this one, JB - it really is just VERY basic plumbing.

However, can you get to the vent fitting on your tank? Get a length of 5/8" hose and remove the vent hose. Put the new hose on the vent nipple and secure the new hose - tie it off to something - just make sure there are no dips in the hose. This is now your new vent hose. The will 100% determine if the event system on the boat is the culprit. You "could" run with the vent hose just removed, but you run the risk of fuel spilling out or water splashing in. Just to cover all your bases, blow into the new vent hose to make sure the vent fitting, itself, isn't clogged (although that is extremely unlikely).

[Keithbaja]

A proper vent hose will have a loop up high as possible next to the vent to the outside of boat. And always ck vent for bugs and nests