1992 Nissan NS70A2

[Newtonsean]

This maybe a long shot but I am troubleshooting a NS70A2 on a boat I recently aquired and I have narrowed it down to either the carbs or the fuel pump (probably not the right term forgive me) that is on the side of the motor. I'm going to try bypassing the pump and letting it gravity feed to see if that's the issue if not I'm going to rebuild the carbs. 2 things I need advice on
1. I have searched high and low but can't find a carb kit
2. Is there anything else I should check before tearing the carbs apart

I can get it to fire and run while I am squirting seafoam directly into the carbs

 

[wrench 3]

https://www.iboats.com/shop/sierra-18-7291-carburetor-kit.html The Sierra catalog shows it fitting the 70A2

Just curious but to gravity feed it are you going to put the fuel tank on top of the Coke machine?

 

[pvanv]

No. That carb kit is for the 25 and 30 hp models. Typical Sierra incorrect cross reference.
The float valve is still available, but the bowl o-ring is NLA.

3B7032400M

FLOAT VALVE Part 346032400 was superceded to 3B7032400M

$10.65

 

[pvanv]

Keep in mind that the 70A went out of production maybe 30 years ago. Parts are getting rare. Carefully disassemble the 2 carbs. Clean them will in carb dip and blow them out with carb spray. Though durable, if you do need a new pump, it is still available:

356040001M

FUEL PUMP ASSY. Part 356040000 was superceded to 356040001M

$85.13

 

[Sea Rider]

Tog gravity fuel feed that motor will need to have some sort of funnel, bottle with attached end hose connected directly to the lower carb. Raise container accordingly for a proper fuel delivery. Can also disconnect the motor connector and connect the hose directly to the lower carb, must prime the bulb till firm in order to fill the carbs and keep priming as to maintain the motor running.

Happy Boating