Badly Cavitating

D

drltnt

Recruit
Joined
Jul 19, 2005
Messages
3
I have recently purchased a 1997 24' crest pontoon boat with a 75 hp force by mercury.After changing props and adding a cavitation plate I still have the same problem. The boat has got 27" pontoons and an angled transom. Cavitation only occurs at aabout 3900 rpm and up and in rough wake . do I have to extened the shaft ? If yes is ther an extension kit available .
 
roscoe

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,665
Re: Badly Cavitating

Have you tried different trim angles?<br />Are you trimmed down all the way?<br />Anything under the boat that may be causing even a slight disturbance in the water ahead of the prop?<br /><br />No extention kit available as far as I know.<br /><br />Perhaps you will need to modify the transom mount to either lower it or change its angle closer to vertical.
 
M

monkeyboi

Seaman
Joined
Jun 27, 2003
Messages
54
Re: Badly Cavitating

is this a tri-toon?<br /><br />what is listed as max hp on data plate?<br /><br />did motor come with boat as package?<br /><br />was prop you took off original for motor?<br /><br />does your's have adjustable transom as detailed by crest web site?<br /><br />at rest how far is anti-cav plate below water?<br /><br />have you tried moving weight to rear to see if situation changes?
 
D

drltnt

Recruit
Joined
Jul 19, 2005
Messages
3
Re: Badly Cavitating

Originally posted by roscoe:<br /> Have you tried different trim angles?<br />Are you trimmed down all the way?<br />Anything under the boat that may be causing even a slight disturbance in the water ahead of the prop?<br /><br />No extention kit available as far as I know.<br /><br />Perhaps you will need to modify the transom mount to either lower it or change its angle closer to vertical.
Click to expand...
 
D

drltnt

Recruit
Joined
Jul 19, 2005
Messages
3
Re: Badly Cavitating

I have tried every imagenable angle,all the way down all the way up and straight vertical .<br />I can't change the mount ,because the motor is all the way down and the steering cable is on top of the transom.
 
K

Koda

Cadet
Joined
Feb 14, 2003
Messages
19
Re: Badly Cavitating

this may help, I have a tracker 20' pontoon witha 1998 Force 75 on it, when I bought the rig it would cavitate reaL bad under full load went to a prop shop and was told to getr rid of the <br />15pX10" and buy a 11pX13 1/4" and the prop shop added a slight cup, end of problem, speed before with GPS 13mph to 15mph after 18mph to 20mph with no cavitation hope this helps<br />Luck David
 
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