Hello folks,
I'm in need of some help with a 2001 Nissan 9.9hp 4 stroke. First I need to turn it into a long shaft. Am I correct in thinking all I need is a long shaft housing (which I found one used) a long drive shaft and long water tube? Will I need gaskets? And secondly I've read that I can turn this into a 15 or 18hp motor by changing the jets in the carb. Is it that simple? If there is anyone who knows how to do this please let me know. Any help would be greatly appreciated as always.
Thanks,
Dave

Nobody has anything?

Well I will jump in a be "debbie downer."

First i would say cost for parts is going to very prohibitive to convert from a ss to ls.
That is if it is even possible to find part or do the conversion at all.

While increasing hp by rejetting is possible on current models I would be surprised one, if you do it on one that old. And second would be a bit surprised if you could do, you could gain that kind of hp. I would assume doubling the hp would require a larger piston, among other things.

That is all I got.

The only thing I can suggest is to look for a Nissan Outboard forum. Like 'orc' stated I would be shocked if re-jetting would have that much impact on performance.


Jim

Many 9.9hp motors are detuned 15hp motors. It's a cost saving measure for the manufacturer and allows them to offer a 9.9hp motor for areas restricted to less than 10hp without designing a whole new engine. Some conversions are very simple. On some Nissans, it's an $8 throttle cam. Some Yamahas, it's a different carb and exhaust. I don't know what's required for the OP's motor. However, a 50% increase in horsepower may require a different prop to take advantage of it.

I looked into converting an 80s Honda long shaft four stroke to a short shaft. Parts are not readily available and cost prohibitive.

I'd sell the motor and buy the one you want.

As has already been said, the cost of those parts, are likely to be more than the engine is worth.

It might be better to sell your engine and buy the long engine of your choice.

And just to be more of a debbie downer, I actually owned your exact engine in long shaft at one time, but needed the short shaft. We could have easily swapped parts if I still had it. I think it got left at a friends house, but we have all moved several times and I have no idea where it ended up.