Converting Nissan NS5B internal tank to an external tank

lmbergholz

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Sep 29, 2017
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I have a 5hp Nissan NS5B with a plastic internal/integral gas tank. The carb has a fuel pump attached to it. Question: can I just simply hook up the external fuel tank with it's in line bulb? I have all the parts, tank, fuel lines and fittings to do this. Does the fuel pump that's attached to the carb remain unchanged? Will the carb flood after this modification? Tanks, I mean thanks for any replies. Larry
 

Sea Rider

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Sep 20, 2008
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If so, rotate fuel **** lever sideways to 3 o'clock position and hook external tank with line and connector, prime bulb firm to fill carb's bowl, pull choke, rotate tiller to start position and pull rope till OB fires up..

Happy Boating
 
Last edited:

pvanv

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Apr 20, 2008
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Here is the way the Factory did it. You want a fuel filter:

002-21005-6_FIG14.JPG
 

lmbergholz

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Sep 29, 2017
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Thank you for all that but I have all the parts including a filter. Question: can I just simply hook up the external fuel tank with it's in line bulb? Does the fuel pump that's attached to the carb remain unchanged? Will the carb flood after this modification? Thanks
 

pvanv

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Apr 20, 2008
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Why would you expect it to flood? That is how Tohatsu did it, so yes, that's the way it is done.
 

km1125

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Aug 10, 2016
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The bulb is only used to prime the fuel pump. The fuel pump is still what regulates flow to the carb bowl and the float and needle/seat stop the carb from overflowing.

So, to answer your question, then YES you can connect it to your external tank and it will not overflow the carb. If you still want the option to use your internal tank, then you can put a selector valve in and and checkvalve in the line from the external tank. This way you can use either tank depending on your situation.
 
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