9.8 TOHATSU BUCKIN

[rocket rich]

THIS IS JUST A THOUGHT, YESTERDAY WHEN MY NEIGHBOR GOT INTO THE FRONT SEAT IS WHEN WE GOT UP TO WOT IS WHEN THE RPM'S SHOT UP TO OVER 6200...... COULD HIS WEIGHT HAVE LIFT THE BOAT UP TO WHERE THE PROP GOT OUT OF THE WATER??? COULD THAT CAUSE WHAT HAPPENED. THAT'S THE FIRST TIME ANYONE WAS IN THE FRONT SEAT IN A YEAR?????

 

[steelespike]

Not knowing the specifics of your setup. Very likely what happened was the prop came closer to the top of the surface and likely ventilated
Very likely the prop got fouled with air causing the prop lose its grip.
When the boat planed that also brought the prop closer to the surface.
Try trimming down a notch and try the neighbor back a seat. Perhaps move the gas tank to the front and the anchor etc.
Tell us about your setup.What size and brand boat?dry weight and capacity? hp rating.
The 9.8 should plane easily with 2 aboard.
Top speed, one aboard lightly loaded should produce about 20 mph on a boat suited to a 9.8 motor.

 

[rocket rich]

MY BOAT IS A 1974, LOWE 15 FOOT FLAT BOTTOM JON BOAT RATED FOR 30 HP, MIDDLE SEAT IS REMOVED ,CUSTOM LIVEWELL TO THE LEFT SIDE. 9.8 A3 2013 TOHATSU. built up transom for extra height of motor. Had it dialed in an was great .then problems with filling gas tank 3.5 gallon, still have it??? bucking, idle's really great at 890-920rpm's most of my things or on the left side, why cause that where they fit good, my big butt 233 lbs in the rear.. That's it

 

[pvanv]

Check for a spun prop hub. It's also possible that holding the bow down allowed the stern up. Can you duplicate the problem?

 

[steelespike]

What is bucking. Does it act like you hit something and then continues on.I don't understand trouble filling the tank,
how is that related to the bucking problem? Would surging better describe the problem?

 

[Star]

In my experience, once the hub starts to slip it will continue until you throttle way down, and it won't buck. I spent two summers trying to diagnose a bucking 15 hp 4 stroke. one cylinder would cut in and out at higher rpm. This would only after running at WTO for 35 to 45 minutes. This motor's ignition is the lost spark system that fires both plugs every time off of a Siamese secondary coil. The coil and stator and wires and caps checked ok with a meter, many times. I finally caught it when the cylinder stayed out for a few minutes. Generally after a restart it would run fine for the rest of the day. I bought a new Yamaha/Mercury coil and it has not acted up since. I hope this was the problem.