Cavitation problem, O/B pontoon boat

[CharlesW]

Re: Cavitation problem, O/B pontoon boat

Originally posted by DeanPA:<br /> Charles, <br /><br />The motor is mounted in the top holes in the mounting bracket, and the motor bracket is right on top of the transom.<br /><br />Short of a motor with a longer lower unit, extending my existing lower unit (if possible????)<br />or lowering the transom, I don't know what else I could do.<br /><br />Shebe, thank you for the correction. My prop looks great, so perhaps it is ventilation and not cavitation as I stated.

It sounds like you have covered all the bases.<br />It just seemed really strange that a manufacturer would set up a motor pod that mounts a motor too high and no adjustment can be made.<br />Where is the anti-ventilation plate in relation to the water and the bottom of your pontoons when the boat is at rest?

 

[DeanPA]

Re: Cavitation problem, O/B pontoon boat

Can't remember accurately enough to answer that, Charles.<br /><br />How would I go about finding out if the Force 75ELPT was a recommended motor for my boat?<br /><br />----And is it possible the wrong motor pod was installed at the factory?<br /><br />----And would it be a huge deal to replace the motor pod? Where does one go about finding a replacement?

 

[CharlesW]

Re: Cavitation problem, O/B pontoon boat

Probably the best source of answers to your questions would be the people that made the boat.<br />Try this link .

 

[DeanPA]

Re: Cavitation problem, O/B pontoon boat

Earlier, I got off the phone with "Bob" at Harris-Kayot. A real gentleman. Even though my boat was bought second-hand and is almost 10 years old, he took a sincere interest in my problem.<br /><br />Bottom line, he suggested two solutions:<br /><br />1/ Install a "StingRay" type of stabilizer on the motor. Bob felt that stood a very good chance of eliminating the problem, and/or<br /><br />2/ Lowering the motor pod by use of spacers. He said this problem is unusual but not unheard-of, and the installation of spacers (he recommended NOT to go more than 1 1/2 inches) was acceptable from Harris' standpoint (not that I'm worried about the warranty or anything, I just didn't want to do anything beyond the pale). Bob went on to answer a question about the nose of the motor pod "plowing" through the water by saying the pod is designed to do that. He even offered to check around the plant to see if they have anything that could be used as spacers "lying around".<br /><br />Wow, was I impressed.<br /><br />Anyhow, since I am only up at the Lake on weekends, and the boat has to be on dry land by the beginning of October or so, I doubt I will be undertaking any major projects until it comes out.<br />I thank everyone for their comments, and if I discover anything that works, I'll come back to this post and "bump" it upwards.

 

[DeanPA]

Re: Cavitation problem, O/B pontoon boat

Update:<br /><br />I have just ordered a set of lowering blocks from Bob at Harris. $50 for six aluminum blocks plus the longer stainless bolts I'll need to install them.<br /><br />When I asked Bob when Harris actually uses these blocks, he told me they use them to mount the motor pod when a "non-Bigfoot" motor is intended to be installed, or boats with the 25" tubes.<br /><br />I don't know a lot about Bigfoot motors, other than that they are extra-long-shaft motors made by Merc, supposedly for pontoon boats with the larger-diameter tubes, so that makes sense.<br /><br />In any case, this should get me another 1.5 to 2 inches of lower unit in the water, which probably couldn't hurt.<br /><br />Thanks for the advice about contacting the manufacturer. I guess I'm used to non-boating product lines, where a 10-year-old item, purchased used, is of no interest whatsoever to the original maker.