Nissan NS5BS Question

Hello all,

First off I'd like to say great site and thanks for the great reads. Very informative and I hope someone can point me in the right direction. I have an old NS5BS (want to say 1996 but I don't remember where I got that from) that I'm looking for some advice on. Basically it starts up just fine, first or second pull, it idles just fine. Everything seems good with the engine from what I can tell. However, I am having an issue where when I get over about 3/4 throttle it's basically like the clutch disengages. The engine will continue to rev but the forward momentum stops. It's stays in gear and as soon as I come off the throttle (down to less than 3/4) the engine starts pushing the dinghy forward again. There are no weird sounds or anything, its just the boat starts moving again. I've looked through the parts manual (thanks for the links) and I see clutch parts are listed on page 36 (#13 - 17), are these parts still available out there and does this sound like the clutch is gone? Any ideas of what this might be? I'm no marine engine expert (or any engine expert for that matter) but I'd be interested in hearing any advice before I start hunting for an outboard mechanic here in Mexico or taking this on myself. Thoughts? Thanks in advance.

-Tom

You likely have a spun prop hub. Time for a new prop. If the clutch assembly was failing, it would be noisy.

Nice. Would there be any visual indicators to a spun prop hub? Thanks for the suggestion! Sounds a lot easier than a clutch issue.

-Tom

Yes. Make a radial line on the back of the prop, from the prop nut out onto the aluminum of the prop hub. A pencil or crayon will work. Then take a hard run where the thrust fails. Then shut down and check the line. If the prop has slipped, the line will now be in 2 segments, showing the slippage. Again, as long as there isn't any chatter, the clutch is probably fine.

Perfect! Thanks for the expert advice.. I will test this on Sunday when I get back from San Diego. Thanks for all your help, and I'll let you know how it goes!

-Tom

So that was it. I ordered a new prop and replaced the old one with it. Boat will now planes up no problems. Thanks for the great advice!

-Tom