I think I know why my 112 is over revving

The last couple of times I have been on the water, my 1996 Johnson 112 VR has over revved out of the hole. It was so bad, in fact that I would have to get out of the throttle for fear of doing some damage. The good news is that the problem would correct itself after I tinkered with the trim long enough (or so I thought)

This weekend the same thing happened again but during acceleration I heard the motor "clunk" into a full trimmed down position. It seemed as if the trim temporarily lost pressure and the motor dropped all the way down.

My trim fluid is topped off. The relays are working OK, and the rams appear to be working properly. Is this over revving the motor changing trim orientation under acceleration, creating prop ventilation? If so, do I need to bleed and re-pressurize the trim system?

Gravysandwich

Re: I think I know why my 112 is over revving

Try tightening the manual release valve.
If that doesn't fix it,

loosen the valve 2 turns and cycle it a few times by hand to bleed the system, re-tighten to 45inch lbs torque.
Top up the fluid and see what shakes.

Re: I think I know why my 112 is over revving

Please explain what you mean when you suggest cycling it by hand.

Thanks.

Gravysandwich

Re: I think I know why my 112 is over revving

Trimmed down should not cause this over revving problem as you are putting more motor in the water. Check the trim seals and also for a spun prop.
Just my 2 cents though.

Re: I think I know why my 112 is over revving

If you have the engine in the tilt position and you give it full power, the engine will normally be forced down hard onto the two trim rams. (full trim position.) It is unusual for the engine to come all the way down to the full tuck position.