Re-Power 1992 Sundancer 290

The Saintly One

New Member
Oct 9, 2018
25
Boat Info
Sea Ray Sundancer 290 1992
Engines
No Engines But looking at an Outboard Conversion
I live in the UK and our Cruising boat usage is somewhat different to your US playgrounds added to the fact we pay stupid amounts for fuel that an original like for like 7.4ltr Merc is going to be prohibitively expensive. So with that in mind what is the Minimum size single Engine I could put in a 1992 Sundancer to still get her up over the hump and onto the plane????
 
I'm sure someone smarter than myself will chime in but I believe you could get V6's in the 290. 4.3L's if I recall correctly. Those would save you some coin vs a big block, I assume.
 
I owned the same boat. The single 7.4 is the minimum size engine for that boat if you want it to plane and perform as designed.
 
I owned the same boat. The single 7.4 is the minimum size engine for that boat if you want it to plane and perform as designed.

Ohh geeze...not enough coffee yet. I didn't even catch the single part. Nice....
 
"Perform" as designed for the American Market as I pointed out you guys are lucky enough to have lots of playground space and cheap fuel. Which is why I am posting the question. Plus the availability of those original mercs are not as plentiful as they might be over your side of the pond

So think of it more like if the boat in 1992 originally had either a pair of V6's or a 7.4L single what would be a modern upgrade to give a usable amount of power and reasonable fuel Economy. presuming that modern engines are better and more fuel efficient than their 26 year old counterparts
 
"Perform" as designed for the American Market as I pointed out you guys are lucky enough to have lots of playground space and cheap fuel. Which is why I am posting the question. Plus the availability of those original mercs are not as plentiful as they might be over your side of the pond

So think of it more like if the boat in 1992 originally had either a pair of V6's or a 7.4L single what would be a modern upgrade to give a usable amount of power and reasonable fuel Economy. presuming that modern engines are better and more fuel efficient than their 26 year old counterparts

Did you give up on your outboard conversion?
 
Yes, can you expand on your thoughts? As of your last post, there was a lot of back and forth but it seemd you were settled on OB's. http://www.clubsearay.com/index.php?threads/newbie-boat-no-engines-3-options.90126/#post-1019071

Are you now dead set on switching your boat from it's original twin engine setup to a single engine? Why did you nix the OB setup - you were so gung-ho on that. You had mentioned that OB's were the way you preferred to go - what changed?

Given your expectations, you could get by with a small block - but you'd probably want one that's been beefed up with some more HP. AND, you will ABSOLUTELY need a B3 drive (a B2 would be "OK") for a single engine on that boat. Well, maybe "absolutely" is not entirely true, but a single prop... boy, you'd be working that engine awful hard and there is a VERY noticeable difference in the performance between the two drives.

I'd also be looking at doubling the size (span) of your trim tabs - or atleast as big as you can go.
 
I think I'm still umming and erring. There is a big underlying concern of the unknown factor of the outboard option. Knowing the boat did come with a single inboard option is a peace of mind. However the biggest drawback is availability of a used 7.4 Merc here in the UK and the fuel economy. My use as you pointed out is limited to the river which is restricted to some degree even on the Thames estuary and the longest trip I'm likely to take is up the Thames which gets restricted again past the houses of Parliament . Hence looking at a single inboard but given that the 7.4L is gonna be 1) old 2) hard to source unless I import 3) Very Juicy for my needs am wondering what other options I have.
 
get a 6.2 small block and a B3 drive and drop fin tabs- it may have enough power to plane with a light load - have you thought about a diesel conversion - steyr, vw, etc may have marine options - expensive and require other supporting mods, but if you can find something used the swap could make sense
 
Are you sure you don't want a trawler style boat? From what you've been talking about, it sure seems that that style boat would suit your needs a whole lot better. Considering the money you'll spend on "making do" with the Sundancer, put that money into something that is already built for the way you want it. At this point, you have very little money into your Sea Ray, and can likely re-sell it for at least close to what you paid.

Maybe something with a 4cyl diesel, single prop? It wouldn't get you the top end speeds that the Dancer would, but it would sip fuel and still clip along at a nice pace - faster than the Dancer would when off plane, anyways.

Don't get me wrong - I'm all for "projects"... but is the end result what you really want.. and what's the final cost outlay to get there? Is it worth it in the end? Just a thought.
 
If repowering...put a diesel in. However, might still be cheaper to buy gas.
 
I feel like we went through this "sell it and buy the boat you want" line of thought during the outboard conversion topic!

Another thought - make her float without engines, use it as a cottage and buy a nice inflatable for less money than you'll have into replacing the engine!
 

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