---

Boat: 1987 15' Super Sport, original with the exception of the battery and gas tank moved under the rear bench seat.
Motor is a 1998 Yamaha 70 2-stroke (70ETLG)

It seems the recommendation is to have the engine raised a few holes, mine is nearly sitting on the transom right now.
Transom Picture
Inside Transom Picture

Here is how it looks running (about 4000 RPM I'd guess):
Running 1
Running 2

When I raise it, should I go all the way to the top? (Hole 4 instead of the currently used Hole 1)

Only the top bolts go all the way though the transom and bracket, the bottom bolts seem to terminate inside the bracket.

I assume I'll need to change the prop also...the current one is a painted SS prop, with "13x7-K" stamped inside.
Prop Picture

With just me in the boat it will turn 5700-5800 RPM if I'm lightly loaded, going in the upper 40s. Loaded as I normally use it, 2 adults and a child, plus a cooler and some beach gear, it will turn 5500-5600 RPM.

---

It looks like you have 4 bolts holding your engine inside the splash well?

I would raise it up another 2 bolt holes and see how many RPMs you turn with your current prop.

---

4 Bolts-Correct
Top 2 go all the way through and have nuts on the outside of the engine bracket. The bottom 2 disappear into the engine bracket.

---

Unbolt your engine and move it up 2 bolt holes. See if your lower bolt holes match up with the new holes on your engine bracket. If not, your gonna have to fill and re-drill.

---

It appears that the motor is mounted to the transom using the "blind" holes in the motor mount (the ends of the lower bolts screw into the bracket). This is pretty typical mounting of a Yamaha 70 on a 15 foot hull. To raise the motor on the transom, you will have to drill new lower holes.

---

There is a great article by Joe with diagram on how to mount the motor and drill new holes. See the "Articles" section on the left sidebar.

---

After you raise the engine you will find that you added some rpms at top end. Before you invest in a new prop, I would have the old one cupped. That will decrease the rpms by 200, and probably add some speed as well.

---

It is definitely mounted using blind holes. I think you meant to say it does high 30's and the prop pitch is 17. I would raise it 2 holes at first and try the prop you have. It will probably need the 19p for top speed with light loads.

---

Yes, the lower holes in the transom ("blind holes") need to be filled and new ones drilled 6-1/2 inches below the top holes and 9-7/8 inches apart, o.c.

This will allow the motor to be mounted "two holes up" or "three holes up" where it ought to be.

See this article for more specific dimensional information:

http://www.whalercentral.com/articles...icle_id=82

---

Well thats not what I wanted to hear. I guess it will stay low for a while. I don't have anyplace to get the engine off and fill the holes and let it sit for the repair to dry....

Thanks for all the replies though!