Maximum weight of outboard

[Gianny]

Hello All I am looking to repower my 1959 AeroCraft AD 18 and have been searching for a long time with no results for the weight I can put on the Transom
It is rated for a 95 Hp and was also available with twin engines. My dilemma is the difference in modern to old engine weight .Current evinrude 1971 60 HP 177 lbs New engine I am looking at 340 to 360 75 to 95 hp.
Any help would be greatly appreciated. Old evinrude in good shape but when it goes difficulty and cost of parts is a problem example 300 for new ignition cap etc.

 

[Ironhorse2022]

First of all, your boat looks amazing. Like it just rolled off the line. As to your question, are you saying the new engine option is about 200 heavier than what you have now ? Are you concerned the extra weight is too much ? If so, it seems to me you could move fuel and battery up front (if necessary) to balance the load and reduce your cargo capacity by 200 and be fine. As long as you don’t exceed max trust ratings, your transom should be fine while your in the water. Now trailering might be a bit tougher on the transom - I’d be sure to use one of those braces that distributes engine weight down to the trailer. I’m no expert on this stuff - just an opinion.

 

[LDUBS]

First I need to say I have no special knowledge. The following is just sort of my thought process if faced with the same issue.

If it is rated for 95HP I wonder what would that era two stroke 95HP have weighed. Doing that would give the high number originally contemplated for an apples to apples comparison.

How does it run with the 60? If the 60 meets your needs you can shave quite a bit of weight by sticking with that HP. For my Honda brand outboard, a 60 HP comes in about 240# which is about 100# less than the 75.

Additionally, I think I would add temporary weight at the transom to duplicate 340# just to see how she sits in the water. Me personally, I would sacrifice a few mph to avoid a stern heavy trim. And that would just be for aesthetic reasons. I don't know if or how a stern heavy attitude would impact handling.

 

[MrGiggles]

I have a 2011 90hp Fourstroke on my 84 Tracker V17, which is rated for 90hp.

My Fourstroke is one of the biggest (it's a monster, probably comparable in size to an older 200hp, basically a baby Verado without the supercharger) and heaviest ever made. It's just under 400lbs. For comparison sake it's safe to say most 90hp 2 strokes will come in around 300lbs.

I lost about 2 inches of freeboard, so I have to be more careful backing into waves and beaching. It doesn't take much chop to start splashing over the transom. Handling wise the boat is not much different. Steering effort was greatly increased, it is not bad at all on plane trimmed out, but low speed is not so good. It would benefit from hydraulic steering. The four stroke definitely has better idle and low speed manners.

I am still able to walk on the rear deck without worry of swamping if the water is fairly calm.

I have considered trading up on one of the new Tohatsu 60s, as they are really light (around 250lbs I think) and supposedly perform pretty well, but I haven't looked into it much.

I'd say your boat will handle the weight fine, but there will be trade-offs, and you may need to move some things around if you have batteries or a large gas tank back there as well.

It seems there is a big weight penalty in going from the 60hp class up to the 75+. To the point where I'm not sure the extra horsepower is even worthwhile, at that point you're basically carrying the weight of another person with you all the time. I only gained 5mph on the top end going from a 75hp 2 stroke to the 90hp four stroke, and the holeshot is not much different.

 

[Gianny]

Thank you everybody for your response I think I will consider staying with the same HP if the gains will not be that much vs the tradeoffs

 

[AlanT]

I've looked into this as well for my boat. The Yamaha 70 comes in about 250 lbs and appears to be the lightest of all the mid-sized engines.

 

[eeshaw]

I've got a 20 foot Mako CC (1973) that I'm dinking around with at the moment. I was having similar thoughts and what I've decided on is using the motor recommendation for the year of manufacture and looking at the weights of motors that were used during that period. From this I look at the maximum hp my hull is rated. Next thing I feel you should consider is the amount of torque the engine is capable of providing. Try to make a compromise that fills the bill and you should be sitting pretty.

 

[sonny.barile]

4 strokes are much heavier than old 2 strokes. Make sure that transom is solid.