NSF9.8A2 Fuel Pump Issue

[Bullie]

I usually stick to my old Evinrudes and Johnsons but a fellow asked me to see if I could get his 9.8 Nissan 4 Stroke working again. I have a very similar, if not the same, motor that my dad uses, a 9.9 Mercury 4 stoke. This fellow had let someone borrow his motor and that person left it laying on the wrong side for a couple days. I have dealt with the same issue with my motor. Anyway, I cleaned the carb up and reinstalled. Before installing the new gas line from the fuel pump to the carb, I gave the bulb a few squeezes to move any old gas out of the line. No gas would move through the fuel pump but it was being pushed into the filter. I pulled the line entering the fuel pump off and gave the bulb a squeeze and fuel shot out as expected.

Is the fuel filter on this motor reasonably easy to rebuild? Is that what it sounds like I need to do? A new one is $57 plus shipping but if I can fix it I would rather do that. I am not familiar with this design but sort of surprised I couldn't push fuel through it.

What do you recommend?

 

[pvanv]

If you are priming and getting flow, but no gas to the carb, a diaphragm in the pump is blown, and you are dumping gas into the oil. If it's just pressurizing the inlet to the pump, a valve is stuck. Yes, new pump parts are available.

If you have the original pump for an A2, there have been 4 revisions/improvements since then. The latest pump is 3H6040007M, with an MSRP of just under $64.
See your Tohatsu dealer.

Yes, it is identical to the Merc 9.9, aside from a slight difference in carb, and possible shifter linkage difference.

 

[Bullie]

I took it apart and cleaned it up. The intake side was completely plugged. I likely need a new diaphragm but it wasn't stretched. I think I will give it a try.

 

[Bullie]

The carb interior looked pretty similar to the fuel pump. I cleaned everything up well and disposed of his old gas, it was bright yellow, and it runs like a new one again. Thanks for your help.

 

[Bullie]

The carb interior looked pretty much the same as the inside of the fuel pump. Leaving a 4 stroke laying on the wrong side is a bad idea. Anyway, after a good cleaning everything is working as it should and the little Nissan is purring again. Thanks for your help.

 

[pvanv]

The condition of the pump and the carb has NOTING to do with which side it was laid on. That's just plain old, bad, spoiled fuel.