I haven't heard of that sort of pump. If you have them it is very uncommon. In a typical dual outboard set up there are normally just fuel water separators, primer bulbs and then the LP and HP pumps on the engine. Maybe you are looking at a fuel flow sensor that looks like a pump? Garmin and others make different versions.
I agree with simple. I put bulbs in and could not get one motor primed. I had to put one of the pumps back in to get the engine to run. I am going to again. I did not mount the primer bulbs vertical the first time. Thanks.
I call them lift pumps.
I am curious about the case where a primer bulb wasn't enough to get the motor primed. As long as the old pumps were removed, the bulb should work I would think.
The bulbs will always work. May see if the antisiphon valve is restricting the flow or the arrow on the bulb was not mounted pointing up.
I use all oem Yamaha, oem Mercury, or Sierra primer balls. Theother aftermarket ones have problems.