Re: Nissan 30hp 4stroke
Do you have an NSF30A with 3 carbs, or a 30B that is EFI?
I would stay away from the glass filter because it could crack if it bounces into something hard. The plastic filter for the 30A, 369022300M, FUEL FILTER, available from any dealer (including me) for $11.07 is in fact translucent, and you can see the fuel level in it. Trapped air/fuel vapor in the filter is no big deal, but if you have an air leak in the line to the tank, you could be drawing less fuel than you need. If you want to purge the bubble out of the filter, disconnect the hose at the fuel pump, and hold the open end up in the air, then squeeze the primer. But any time you run dry, you will probably get some air, and it will lodge in the high part of the filter. Again no big deal. Remember that the filter is on the suction side of the pump, so pressures below atmospheric are normal, and the bubble may reappear. A lot has to do with the kind of fuel you are running and the ambient temperature. The 30B has a translucent settling-bowl type of filter, and a vapor separator, so minor amounts of air are no big deal either.
Your symptoms could be a lot of things, including water contamination in the fuel or a weak pump. The A model requires that you idle the carbs dry religiously at the end of each day, or you risk varnishing in the carbs. If you are having that bogging with a B model, you may need to clean or replace the injectors.
So... whip out your Factory service manual, and start by diagnosing the fuel, electronics, and mechanical systems (in that order).
