Honda BF50AX dies at higher throttle settings.

[Bakeys]

Hello experts!
2000 BF50AX on the back of a pontoon.
Been running great all summer. Couple weeks back was at 2/3 throttle or a little higher and it just bogged down and acted like it was starved for fuel. Dies and then restarted. Started back up and ran at idle and comparatively low RPMs. Did this a couple times.
I just got the boat/engine last year so I figured - bite the bullet and replace the fuel pump and filter.
Bought the genuine Honda pump and filter. Go in to take it apart and it has a clear in-line filter (not Honda). Replaced the fuel pump with no issues. Go to replace the filter and the filter inlets (barbs) on the genuine are larger. So it looks like someone replaced the fuel line and filter. At least the line going to the pump.
So I reinstalled the old filter and took it out for a test run. (Old filter is clear and appears uncontaminated.
Ran like a scalded dog for the better part of ten minutes. So I figured the fuel pump was weak. It fell on it's face for a brief second or two and then smoothed out. So I thought I had it taken care of. Headed for home at 3/4 throttle - bwahhhhhhhhhh, it does it again. Starves for fuel and the engine shut right down. Didn't want to start at idle. I ended up starting at 1/2 to 3/4 throttle and it coughed and sputtered and eventually smoothed out. Made it back to the hoist and parked it.
I took a sample from the bottom of the fuel tank and it's clean and uncontaminated.
So now I need to go back and eliminate the fuel filter as the culprit. I'll buy an in-line filter that fits the hose or buy a hose that fits the genuine Honda filter.
But what else COULD it be?
Thanks for the assist!

Boat on!

 

[MattFL]

How does the squeeze ball feel when the problem occurs? Also check the tank air vent and for air leaks in the fuel line.

 

[Bakeys]

How does the squeeze ball feel when the problem occurs? Also check the tank air vent and for air leaks in the fuel line.

Primer bulb is hard. ( I thought the same thing. ) Tank is vented. (I loosened the cap just in case. It opened freely and there was no sucking sound.)
HOW does one check for leaks in the fuel line? Guessing there's be a raw fuel smell.

 

[MattFL]

If the ball is hard then vacuum leaks are unlikely. Next time the problem happens, immediately crack open the bowl drain on each if the carburetors and verify that the bowls are nearly empty. Electrical and fuel problems can appear similar sometimes, empty bowls will confirm the carburetors are running out of fuel.

If there are empty, pop the fuel line off of one and see if fuel flows freely when you squeeze the ball. If not then work your way backwards towards the ball to figure out where the flow gets obstructed.

 

[ahicks]

Honda fuel pumps are pretty solid in my experience. They keep going and going. Based on the price of a new one, and the fact they aren't rebuildable, that's a good thing!

What I don't trust is today's fuel lines. If you can beg borrow or steal (kidding) another tank and fuel line w/primer bulb that's where I would start. I've also seen the under hood line from the fuel line connector to the fuel filter collapse or kink. Just because the line looks good externally doesn't mean it hasn't collapsed internally.