Boat porpoising

[Trains1938]

Hi ALLdodge, I will post another pic. so you can see the hole thing.

Hi Pattromny, The motor is 1973 Johnson 65 hp. Will try to post a pic of the whole motor.

 

[Trains1938]

No Title

It has been requested for these pic's so here they are

 

[alldodge]

Your motor is to far away from the transom. The motor has about a 15 to 20 degree angle from the transom. Your transom is about straight up and down, if it was tilted back a bit more, your trim out should not be an issue. I don't know how to fix, the reverse hook needs to be there for backing up. The motor stop needs to be there so the motor can push against the transom.

just spit balling but I think using some kind of metal wedge between the motor and transom

 

[Patfromny]

The motor is also pretty high. The cavitation plate is already an inch or more above the lowest point in the hull. Looking at the position of your engine I would say you should trim it one notch up-to the second hole. It seems to be leaning in toward the hull. This alone might solve your problem. It will also lower the cav. Plate too.

 

[sphelps]

Iboats only came up with one in a search but these behind the mounting bracket will give the motor more down trim ...
http://www.iboats.com/Transom-Wedge/dm/view_id.40151&s=sol

 

[Trains1938]

Patfromy, The motor was in the 2ed notch up when I bought I bought it. That's why I lowered it, but did not help.

Alldoge How does the motor wedge work? never seen them before.

sphelps Looked at these but they look like they would put my motor further away form the transom. Not sure how they work. Do you have any pic of them install on a boat?

 

[alldodge]

I use this method

 

[Trains1938]

Alldodge, Thanks for the come back.

 

[sphelps]

Trains the fat end is on top .
I think I have a pic of mine installed I can post later

 

[sphelps]

Here is a picture ,,

 

[alldodge]

I think that would help. Get the drive more tucked under the boat.

 

[Trains1938]

Hi sphelps, Thanks for the picture. Do they come in different thicknesses?

 

[sphelps]

Yep I think in a few different deg of angle .... I thought iboats had more of a selection unless I did not do the search right ... You would need to find the right hole pattern for you o/b .. Some are a universal fit ...

 

[Trains1938]

Hi Teamster, I have found out that the prop is a Michigan 011004. That is a 13 x 9 prop.

 

[Patfromny]

I'm sorry if I'm hijacking but I'm kinda lost here. Why is it so important to have the motor tucked in to the boat? I'm honestly trying to understand this. If closer is better than how do the add on trim and tilt mechanisms work? I would imagine they push the engine even further away from the transom. What is a good distance between engine and transom? Sorry once again, I just want to understand why trains needs to move the engine closer.

 

[Watermann]

It's not that the motor needs to be closer rather the wedge will increase the distance of the powerhead making for more of a degree of tilt inwards toward the transom for the lower which will give the bow more lift. But the motor will actually be further away due to the wedge,

 

[alldodge]

It's how weight is distributed and the angle of the tilt. With power trim the drive starts parallel to the transom and in some cases even a bit under. As speed increases the rim can be move out away from the hull until the proposing starts. To much trim starts proposing, to little causes the bow to plow.

In the pic below note that IF the drive was parallel (the green line) then there would probably not be an issue. The distance between the green and red lines is what needs to be changed to find the sweet spot

 

[Patfromny]

Ok, I got ya now. The pic above is with the pin in the lowest position. The wedge will essentially add a pin position and probably make the engine more tunable. I didn't notice the pin position before and was lost as to why everyone thought the engine was so far away from the boat. Thanks for the explanations guys. Carry on...lol

 

[Trains1938]

Hi sphelps, After reading Alldodge explanation on the subject, I think the wedge is the way to go. Question: What degree of wedge do you use on your boat?

 

[Trains1938]

Hi Alldodge, Your explanation is great and the pic shows it. I think the wedge is the way to go. Just don't know what degree to use/start with. What would you suggest?