Mercury 20 hp model 200 cavitation problem

[bowhunter97]

sorry for the cap letters but i copied and pasted it from ms word... sorry <br /><br />HELLO, I AM HAVING MAJOR PROBLEMS WITH GETTING MY BOAT ON PLANE... HERE'S THE DEAL:<br /><br />THIS IS A STRONG MOTOR (ALL JUST REDONE) AS SOON AS I GET ON PLANE, THE PROP SEEMS TO SLIP. I INSTALLED A NEW PROP. SAME PROBLEM. I MARKED BOTH PROPS AND FOUND OUT THAT THE PROP IS NOT SLIPPING. <br /><br />IT REALLY "DIGS" IN ON THE HOLESHOT AND AS SOON AS THE BOAT STARTS TO SCOOT, IT "SPINS OUT" SO TO SPEAK... WE RAN THE BOW OF THE BOAT AGAINST THE SHORE AND TURNED IT FULL THROTTLE. THE MOTOR JUST KEPT DIGGING AND DIGGING, IT NEVER SLIPPED A BIT. TOOK IT BACK OUT AND IT REPEATED THE SLIPPING WHEN ON PLANE. TOOK IT BACK AGAINST THE BANK AND IT RAN STRONG... BEFORE I HAD THE MOTOR WORKED ON IT NEVER ONCE DID THIS. THERE IS NOTHING ON THE BOTTOM OF THE BOAT TO MAKE IT "DRAW AIR" OR ANYTHING... MY MECHANIC IS CONFUSED BY THIS AS MUCH AS I AM. ANY HELP IS APPRECIATED... THANK YOU IN ADVANCE ! STEVE

 

[12Footer]

Re: Mercury 20 hp model 200 cavitation problem

Where is the cavitation plate in relation to the very bottom of the hull?<br />Does the cavitation worsen in turns?<br />try setting the trim pin (in the hinge plate) in a different hole, to tilt the leg up a little, or down a little. My guess is, this pin fell-out, or was removed when it was werked-on, and put back in a different set of holes.<br />Just a few things to try. Good luck.

 

[Old Jarhead]

Re: Mercury 20 hp model 200 cavitation problem

Sounds like your engine is either mounted too high or trimed out (up) too far.<br /><br />Cav plate should be even with, or just above, the lowest part (bottom) of the hull. <br /><br />Good luck. <br /><br />BTW... Maybe I'm missing something here but I'm a little surprised that your machanic is confused with this problem.

 

[bowhunter97]

Re: Mercury 20 hp model 200 cavitation problem

I have tried all of those things... the cavitation plate is perfect in regards to the bottom of the boat. <br /><br />The pin is on the very last one. (the same as it was before it was worked on) I have not tried lifting it a hole or 2 to see if that makes a difference. Someone told me that if the exhaust tube is not in the boot correctly that some exhaust could be escaping from somewhere other than where it should and that could be getting air to the prop causing it to spin out??? Does this sound even remotely possible. At this point I'm leaning toward a new purchase. (not brand new, new to me) thanks for your help!<br /><br />Steve