how much weight can I hang off my transom

**jpf091959** · 02-28-2025, 05:41 PM

I am restoring a 1980 Taylor Stiletto, 20.5ft modified tunnel and kind of narrow hull.

they were designed for the lightweight two strokes outboards or big block power, outdrives, v-drive or jet. I would like to mount a modern 4 stroke outboard on it. I was thinking 175-200hp but I have access to a 250xs 4 stroke at a good price. but those weigh over 500lbs, all hanging off the back.

Anyone know of a formula or table that help determine the weight limitations and setback?

**racer** · 03-07-2025, 06:08 PM

IMO that V8 is too heavy and will be top heavy on that boat. Wet weight is close to 550 pounds

**WaterZebra** · 03-07-2025, 06:18 PM

Originally Posted by jpf091959

I am restoring a 1980 Taylor Stiletto, 20.5ft modified tunnel and kind of narrow hull.

they were designed for the lightweight two strokes outboards or big block power, outdrives, v-drive or jet. I would like to mount a modern 4 stroke outboard on it. I was thinking 175-200hp but I have access to a 250xs 4 stroke at a good price. but those weigh over 500lbs, all hanging off the back.

Anyone know of a formula or table that help determine the weight limitations and setback?

(1) Find the BIA HP rating for that production year model hull
(2) Find the max HP value.
(3) Look up any Mercury or OMC HP model that matches the spec and then look up the dry weight for that engine. Definitely going to be lighter than a 250 XS 4 stroke.

**David - WI** · 03-07-2025, 06:46 PM

It's not too hard to lose 100# to offset the extra stern weight of the heavier motor if you can switch to a lightweight anchor, LiFePO4 battery, plastic fuel tank, aluminum or plastic spare prop, even a lightweight engine cowl if available... it's just whatever you think you can live with (I did all of them and kept the 2-stroke V6).

**pcrussell50** · 03-08-2025, 11:55 AM

You've run into the problem that all of us who like smaller lighter hulls, face.

Even a utility hull like a classic Whaler... I have a Montauk (rated for 90hp), with a 90hp Mercaha FourStroke, and it is H-E-A-V-Y. Even on a utility hull like a Whaler, you can tell. I like the smooth quiet idle of the motor. But. Damn.

Seems like the "right" way to enjoy a heavy modern four-stroke, is with a heavy modern hull designed to float it. At that point, with automotive sized displacements in outboards, your hp/dollar might go further with modern automotive v8's and out drives.

-Peter

**Glastron1987** · 03-08-2025, 02:02 PM

Over the years I've been noticing boats and motors getting fatter, just like servings of French fries. Sometimes I think about upgrading to a new rig, but that extract fat is a turn-off to me. Do I really use more gas with an old rig? I have my doubts.

**WaterZebra** · 03-08-2025, 04:06 PM

Originally Posted by David - WI

It's not too hard to lose 100# to offset the extra stern weight of the heavier motor if you can switch to a lightweight anchor, LiFePO4 battery, plastic fuel tank, aluminum or plastic spare prop, even a lightweight engine cowl if available... it's just whatever you think you can live with (I did all of them and kept the 2-stroke V6).

Gross weight of the package has nothing to do with it. You can put the boat and engine on a "diet" if you want but it's the peeling loads of the 4 strokes on the transom structure that must be addressed. You can beef up the "rump" with additional transom knees or aluminum but if you mount that 4 stroke and ignore the weight difference you might see cracking develop in the transom area both from the inside and out. Then you have a repair mess on your hands.