Nissan NS5B dies when revved up

[drumbeater]

I've got a 5hp Nissan that hasn't been run in a while. It will crank and idle, but dies when throttle is applied. It does ok if you fiddle with the choke the whole time, but I know that can't be good for the engine fuel/oil mixture.

I took off the carb and cleaned it reasonably well and took the fuel pump apart and the diaphragm looks good. New fuel, new fuel tank and lines. I'm thinking there is some microscopic problem with the carb, but before I spend $50 on a rebuild kit, I figured I'd ask here.

I have not checked/confirmed adjustment screws on the carb. I don't know if they have been turned at all and don't know initial settings for fuel mixture adjustment.

 

[Sea Rider]

Re: Nissan NS5B dies when revved up

Is it a 2 or 4 strokes ? are you using internal or external tank ? If you clean carb properly no need to buy a carb rebuild kit. Probably carb still needs a good clean out soaked for some hours in proper carb cleaner.. Adjustment screws are for idle overall rpm, if at idle speed gives shutting engine problems, is badly adjusted, no issue with them once at fast idle & upwards.

Happy Boating

 

[TOHATSU GURU]

Re: Nissan NS5B dies when revved up

Almost certainly the carb. At least a three hour soak in real carb cleaner.

 

[pvanv]

Re: Nissan NS5B dies when revved up

Almost certainly the carb. At least a three hour soak in real carb cleaner.

Yep. Remove carb. Do a Complete disassembly. Soak all non-rubber bits in real carb cleaner, such as Tyme, Gunk, or Berryman's (available at auto parts houses in 1-gal. cans) for 4 hours at room temperature. Then spray out all passages with liberal amounts of generic spray carb cleaner. Then... do a careful reassembly, paying particular attention to float height. Initial setting for the idle mixture should be about 1-3/4 or 2 turns out.

 

[drumbeater]

Re: Nissan NS5B dies when revved up

My local boat shop told me I can put it into their ultrasonic cleaner for a while.
The float doesn't look adjustable. It pivots on a steel pin and there is no metal "arm" to bend.

 

[pvanv]

Re: Nissan NS5B dies when revved up

You still need to verify float height. If it's wrong, you will need to replace the needle and or float (comes in the kit).

 

[TOHATSU GURU]

Re: Nissan NS5B dies when revved up

The float is not adjustable...But, it is bendable and that makes it sort of adjustable...

 

[drumbeater]

Re: Nissan NS5B dies when revved up

Had the carb cleaned in an ultrasonic cleaner and motor runs great now. Another problem though for another thread.