CONTINUOUSWAVE

Hello all I have a classic [13-foot Boston Whaler boat] around 70' [I don't think you have a 70-foot Boston whaler boat. You probably were trying to write "c.1970." Please use FOUR DIGITS for years. Expressing years with two digits and an apostrophe in the wrong place causes confusion--jimh]

I believe [the classic c.1970 13-foot Boston Whaler has] the 15-inch transom.

When I bought the boat a 1998 Mercury 40-HP short-shaft outboard engine was mounted with only the top two mounting bolts and was pushing against the transom. [This mounting] worked for the most part.

To level out the dip in the transom I bought a transom adapter which allows the engine to be mounted with all four bolts but is now too high in the water.

Has anyone here had the same problem?

Has a way been found to use a jackplate or something to get the motor lower in the water by a couple inches without buying a long shaft motor?

If you have a boat with an transom designed for a "short-shaft" or 15-inch-shaft engine, and you have an engine with a 15-inch shaft, I don't see why you would undertake the steps you have. You have purchased something to raise the transom height for a 20-inch engine, and now you want to lower the engine with an inverted jack plate. This seems upside down, to me.

Bolt the 15-inch shaft engine to the unmodified transom. What is preventing this?

There are a dozen or so members over the years who, for one reason or another, installed a 20 inch (long) shaft engine on a classic 13' model that had a transom designed for a 15" (short) shaft.

There are 3 options:

1. Rebuilt the transom.
2. Install a "transom adapter" product, aka Kentfab Adapter
3 Install a jackplate.

While it is highly recommended owners avoid these 3 options, if necessary, option 3 is least cost and complexity.

Options include:

Jackplate: https://thmarinesupplies.com/collections/jack-plates/products/hi-jacker-fixed-jack-plate-4-inch

Adapter: http://www.nausetmarine.com/shop/boston-whaler-transom-riser/

In your case, please post a photo of the motor installation and also provide measurements of the bolt holes used on the transom.