70hp engine mod

[swampfox]

i have built a 70hp merc an want to mod it to run on a hydro with a 16.5 inch transom is this possible an where should the cutting begin

[sam]

Which of the many 70 hp Mercs? There have been many over the years

[Dave M]

Low As you Go

I would get the center of Gravity as low as you can without sinking while sitting still. Typically the FE's are run on transoms from 7 inches to 12 inches. Personally my transom is 12" tall. But make sure your down housing won't put your prop shaft 6 inches below the boat when you lower it. Depends on your down housing. Ideally you want the propshaft somewhere from 1 3/4" to 1/2" below the bottom. Some run higher than that, but I think you can run into handling trouble in rough water if you go to high.

[swampfox]

70 merc mod

thanks for the info but the question i have is from the powerhead down how do i get it short enough does anyone make a midsection , adapter plate exhaust tuner, an does anyone have any phonenumbers that would be helpful

[Dave M]

Tower Length...

You have to machine the clamp brackets down to the length you want....

I recommend a Bass tower if you are running your exhaust out the bottom, they are easy to cut the hole in, and you only have to cut a little of the webbing out for the pipe under it.

If you are running chambers, megaphones, or that one like Jeff Akers has as his avatar going out the top you can go with a Lee Tietz tower, Machined Components. Tietz tower won't work if you are dumping exhaust out the bottom.

His contact and Bass contact info is on this website as a sponsor I think. I know there are a lot of folks that build their own towers. I also think Steve Rowskowski builds a tower, not sure how adaptable it is to a 3 holer, I have not see one in person.

You basically have to accept the tower housing length as it is made; there is no magic measurement unless you are building your own.

Look a little on this website, you will find a lot of the info you are asking. Especially in the Tech area. There are exhaust plates made, etc. Runne sells exhaust, and many make their own. If you are handy, it is not too hard. Just time consuming as you whittle away !!