Cannot trim motor up - Porpoising

[atengnr]

Re: Cannot trim motor up - Porpoising

I think we may have some positioning issues going on here. Hopefully he can fill everyone in on what we've been talking about offline.

Yes, the anti-cavitation plate is not parallel to the hull at full down position. It is inclined slightly.

Can this be improved??

 

[Dhadley]

Re: Cannot trim motor up - Porpoising

OK, that will explain the porpoise and the nose-high holeshot. The question is -- why is it that way now and not with the older motor?

It's easily solved and we can take care of the height deal all at the same time. A Bob's Machine 4 in 1 manual jackplate can be assembled so it has negative trim. And it can be assembled so it has minimal (2.5") setback. Obviously it will give you the option of more height very easily.

The mystery still remains as to how all the positive trim in the full down position got there.

 

[atengnr]

Re: Cannot trim motor up - Porpoising

How does one set the full down trim angle?? It seems that the full down trim angle would depend on the angle of the transom??

 

[Dhadley]

Re: Cannot trim motor up - Porpoising

The transom angle didn't change between running the older motor and the newer one unless you had the transom replaced. Or the old motor ran wedges that aren't there now. When the motor is in the full down position with the thrust rod removed you should have several degrees of negative trim.

The motor you're running now never gets to parallel, let alone to negative trim in the full down position. Something has changed to prevent the motor from coming all the way down, we just have to figure it out.

 

[Dhadley]

Re: Cannot trim motor up - Porpoising

Even if nothing has changed we still need more negative trim angle. Wedges will provide that easily but we need more height too. Regardless of how we got where we're at, the Bob's convertable plate will solve all the issues simply.

 

[atengnr]

Re: Cannot trim motor up - Porpoising

Even if nothing has changed we still need more negative trim angle. Wedges will provide that easily but we need more height too. Regardless of how we got where we're at, the Bob's convertable plate will solve all the issues simply.

Where can I find this product?

 

[Crownie2]

Re: Cannot trim motor up - Porpoising

http://www.bobsmachine.com/main2006.asp

Are we sure the thrust rod has been removed??

Also - Bob's offers transom wedges which is another option if you don't want to buy the convert. plate for some reason...

 

[atengnr]

Re: Cannot trim motor up - Porpoising

I dont understand, can I run the boat without the pin? Is it not needed at all??

 

[Dhadley]

Re: Cannot trim motor up - Porpoising

The motor rests on the trim rams, not the pin (thrust rod). We've been talking about the pin being removed. Is it still there?

 

[atengnr]

Re: Cannot trim motor up - Porpoising

The thrust rod has not been removed. I would expect that this will allow the AV plate to be nearly level to the hull, however, since all I do is cruising with this boat, the acceleration is adequte as it is currently.

The next step IMO, is to decide about the jack plate, because I need to get the motor higher, however, Im not sure this transom is up to the added loading due to the offset from the jack plate. I felt like I was pushing it already when I added this motor....

I want to assess the transom and decide if I should replace it this winter, then add the jack plate, or simply leave it alone for a few years. Transom does not flex, but had water in it for many years prior to getting it dried out this summer.

 

[walleyehed]

Re: Cannot trim motor up - Porpoising

Acceleration is not why we want you to remove the pin...if it's stopping the engine from going on down a bit, at cruise, that's when it's going to porpoise and cause problems. I pulled my pin about 500hrs ago on my 200 V6..if it's in there, take it out.

 

[atengnr]

Re: Cannot trim motor up - Porpoising

Acceleration is not why we want you to remove the pin...if it's stopping the engine from going on down a bit, at cruise, that's when it's going to porpoise and cause problems. I pulled my pin about 500hrs ago on my 200 V6..if it's in there, take it out.

I need the pin for keeping the engine's weight off the trim rams when trailering, correct? So reinstall when I trailer?

 

[walleyehed]

Re: Cannot trim motor up - Porpoising

What hole is that pin in? What hole, starting with #1 being the closest to the transom.