New power on an older hull?

[tillerman]

Some of the newer 4 stroke and etec engines weigh quite a bit more than their vintage 2 stroke predecessors. As an example, I have an older Nissan 40 2Stroke on my 16' tin boat. The Nissan weighs 159#, a new 4Stroke 40hp Yamaha weighs 214#, and a new Evinrude 40 Etec weighs 240#.

My question is: if I buy and older 70's Starcraft hull rated at 140hp can I just bolt on modern 140hp 4 stroke power?

Thanks for the help,
John

 

[trendsetter240]

Re: New power on an older hull?

Hey tillerman, I went through the exact same questions when repowering my 1969 SS170.

In the end if was determined that weight isn't really going to be an issue but the condition of your transom and how low the stern sits in the water with it's current engine is.

Unless it has been replaced recently, that 30 year old transom is not going to be as strong as it was from the factory. You should ensure that you have a transom saver for trailering a motor with that extra weight.

To be on the safe side, thoroughly inspect the transom and if it is still solid I would go with something like a 115hp engine. This will provide for some weakening of the transom over the years.

Hope that helps.

 

[Huron Angler]

Re: New power on an older hull?

I'd recommend rebuilding the transom if necessary and go with a new Evinrude Etec with direct fuel injection and internal oil fill. They should weigh less than a 4-stroke, surprised to hear they aren't...

I've been out with a 2009 60hp Etec on a 17ft aluminum boat rated for 75hp and she absolutely flies out of the hole and up to 35-40mph quickly. Also no maintenance for 3 years...best outboard motors I've ever seen

 

[tillerman]

Re: New power on an older hull?

What's the best way to determine if a transom needs repair on an older Starcraft?

 

[Kainon]

Re: New power on an older hull?

poke it with an AWL or other poking device like a screwdriver? If it goes in.. its time. can also tap with a hammer or handle of screwdriver, softer duller sounds means... it's time.