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9.8 Nissan tohatsu high torque

G

Gypseas

New member
Hi all,

I am in the market for a 9.8 kicker and was wondering if you could share the good the bad and the ugly.

Thank you in advance.
Cheers
 
The 9.8A3 is a mature design. In order to make it "high thrust", there are two different 4-blade props, a 7 pitch and a 5 pitch. That configuration is typically used with a very heavy load (such as my 8,000-pound sailboat), or a service-type barge. Those props are not usually used for a fishing kicker, unless it's otherwise impossible to slow the boat down to proper (2 MPH) speeds without resorting to idling. The 9.8 is very quiet, efficient, and the lightest weight in its class. It's so quiet that on some motors, you can actually hear a "whine" sound at around 2,000 RPM, that is actually an intake harmonic. You'd never hear that on a louder motor, because the mechanical sounds of the motor would drown out the intake whine. Being a 2-cylinder, it's pretty smooth, and has crisp throttle response once fully warmed up. Like any 4-stroke, the harder you run it, the better it runs. Also (again this holds for any 4-stroke), extensive idling, especially when not broken in yet, and particularly in very cold water, may contribute to "making oil". It is important to run the carb dry at the end of the day (like any motor running on today's junk fuels), or risk varnishing in the carb. We have had very few warranty repairs on the 9.8. It's my favorite Tohatsu 4-stroke design (and the one I have on my personal saiboat).
 
Depends.

For "just motoring", the 3B2B645140 3-blade 7-pitch props (which come stock on the long shaft models) will work, but for more severe conditions, a high-thrust prop will be a big help.

For example, a Stiletto 27 (1725 pounds) can run a single 9.8, equipped with the 7-pitch 3B2B645120 4-blade high-thrust prop (which comes stock on the long shaft motors with power tilt) in preference to the cupped, 3-blade prop.

Your boat, double that displacement, and equipped with 2 motors... If you need good reverse thrust, and will be powering into headwinds, I would consider using the 7-pitch HT props, because although the boat is relatively light, it will present a lot of windage, requiring the thrust of those elephant-ear props. You should not need to go down to the 5-pitch 3B2W645110 prop (which comes stock on the ultra-long motor), as you don't have a ton of displacement, and might hit the rev limiter at WOT.
 
Paul,

Thanks for your advice. I think I will follow it and go with the 7 pitch HT. I have a new XLS 9.8 that came with the 5 pitch and a 2010 that came with a 3 blade. Would it be a bad idea to buy a 7 pitch HT for the new one and compare it with the 3 blade on the older one to see how each one works both at "cruising" speed and maneovering?

bax
 
That would make for a good test. It's guaranteed that the HT props back down better (because they don't suffer from exhaust ventilation nearly as much). But... They may limit your top speed. Please let me know your "real world" results, especially if you have tachometer/gps/stopwatch figures.
 
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