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NSF9.8A2 Fuel Pump issue

B

Bullie

Regular Contributor
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?
 
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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.
 


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.
 
The carb looked about the same as the interior of the fuel pump. Laying the motor on the wrong side and leaving it there is a bad idea. Anyway, it is running like new again. Thanks for your help guys.
 
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.
 
Ok. I need re-educated on this subject I guess. There is no way that oil gets into the carb when the motor is laying on the wrong side?

The reason I ask is that my dad left my 9.9 Mercury on the wrong side and the carb was full of oil when I took it off. It was quite a pain to clean it all out. I assumed, in the case of this Nissan, that the oil flowed back into the fuel pump and, combined with the fuel, plugged up the intake side of the pump. It was a solid mass of what almost looked like dirt. The little plastic disk that you can see in the picture looked to be covered in oil when I removed it from the pump.

The gas was very bad like you said. It was a bright yellow color. The owner disposed of the old gas and I picked him up a few gallons of non-ethanol fuel.
 
Yes, oil can get into the carb. When that happens, we just open the drain. That other goo is clearly from old gas.
 
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