Converting a Nissan NS8B to a NS9.8B

[Chuckv43]

I have a 2002 I believe, Nissan NS8B I bought new in 2003. It hasn't seen much use since 2005, but I remember that you could convert it from 8HP to 9.8HP very easy by either re-jet or maybe change the whole carburetor. I've got it on an aluminum 14' 36" bottom Jon boat that weighs in at 135LB, so I could use the extra punch.

 

[pvanv]

Re: Converting a Nissan NS8B to a NS9.8B

Never a re-jet to change hp. In some cases, a carb change would do the trick. In your case, the block is different from the NS9.8B, so not ecomonical to change over everything. Sorry

 

[Chuckv43]

Re: Converting a Nissan NS8B to a NS9.8B

Never a re-jet to change hp. In some cases, a carb change would do the trick. In your case, the block is different from the NS9.8B, so not ecomonical to change over everything. Sorry

Thanks for the quick reply, but I was surprised by it!

I had read earlier post where that was done?? According to the specs, they are identical in every way except the Jets?

 

[pvanv]

Re: Converting a Nissan NS8B to a NS9.8B

Thanks for the quick reply, but I was surprised by it!

I had read earlier post where that was done?? According to the specs, they are identical in every way except the Jets?

No, there must be a mistake in that posting. Richening the jets will only serve to make it run bad and foul plugs. Changing carbs will over-carb the motor, making it stumble at tip-in (coming off idle to power).

Now then, on the NSF series (4-stroke) motors, you CAN change carbs from the 8 to 9.8.

 

[Chuckv43]

Re: Converting a Nissan NS8B to a NS9.8B

No, there must be a mistake in that posting. Richening the jets will only serve to make it run bad and foul plugs. Changing carbs will over-carb the motor, making it stumble at tip-in (coming off idle to power).

Now then, on the NSF series (4-stroke) motors, you CAN change carbs from the 8 to 9.8.

Once again thanks for your response to the question.

Chuck