going to a newer engine
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Thomas Mackin
- Posts: 31
- Joined: Sat Aug 28, 2010 11:27 am
- Location: Eagle River,Wi
going to a newer engine
I have done the assement on my new 58 Sea Lancer and when completed will have an excellent and strong hull. I am an OMC guy and on my chain of lakes tilt and trim is very handy. I am looking at a 1989 Johnson 70 and have seen several 85's from the late 1970's. They changed to prop rating in 1984 so the 70 is lighter and I feel best for the boat? After 1980 they went to 90 hp but the tag on the boat says 85. My old steering was in bad shape so will go to teleflex and use the Thompson wheel. Your thoughts on this will be appreciated! I will have a beautiful boat but I realize not a complete show boat. Thanks, Mac
Big Mac
What engine was orginally on the boat, would be a good place to start, do you still have it, how did it do?
Horse power ratings mean little, as the real punch from a given amount of hp has changed over the years. Prop shaft power now compared to crankshaft in 58 and props that deliver more thrust for a giver amount of hp have improved. Engines have gotten heavier per hp, with the new 4 strokes.
My 2006 Merc 4 stroke 25 has 1 mph advantage over my 1960 Evinrude Lark ll 40 hp. The Merc will go almost 3 times the distance on a gallon of gas!
My guess is the 70 hp would be the better of the choises, More fuel efficent and more than enough power. Ligther than the 1958 50hp OMC. The 85 would idle much better and be smoother, although would provide much more speed than the hull has orginaly thought to be able to handle. The 85 is a more durable engine. In all fairness to the hp rating, 85 was bigger than was available in 1958 as a single, so that hull was never tested with anything bigger. A good running 85 prop shaft hp could push your hull, if straight in the upper 40's maybe 50 mph.
My top pick if you are not worried about matching years would be a recent 4 stroke 50 hp, or 60 hp as a max. Top speed could be 35 with the 50 hp, if your bottom is good and about 9/10 mpg at best cruise of 20/25.
Many of your boat were most likely orginaly powered with a single OMC 35 and did fine, which means for equal performance a Merc 25 4 stroke would work and give tops speeds in the low 20's, and give 10 mpg plus.
If you bottom is not staight anything over 20 mph could a handful to drive.
The best solution would be to try several engine sizes to find the one that feels best, just hook up the sreering and manualy work the gas by hand at the engine to see how your hull reacts to power, takes two but might be worth the experiment. A tiller arm 25 to 40 could be a good place to start.
My 1960 Cruiser's 16' 202 runs easy 23/24 and tops at 28 with a 1960 Evinrude 40, does easy 35 and has a 40 hp top with my 1960 75 hp. As most of my running is at 20 or less the 40 works best for me.
Horse power ratings mean little, as the real punch from a given amount of hp has changed over the years. Prop shaft power now compared to crankshaft in 58 and props that deliver more thrust for a giver amount of hp have improved. Engines have gotten heavier per hp, with the new 4 strokes.
My 2006 Merc 4 stroke 25 has 1 mph advantage over my 1960 Evinrude Lark ll 40 hp. The Merc will go almost 3 times the distance on a gallon of gas!
My guess is the 70 hp would be the better of the choises, More fuel efficent and more than enough power. Ligther than the 1958 50hp OMC. The 85 would idle much better and be smoother, although would provide much more speed than the hull has orginaly thought to be able to handle. The 85 is a more durable engine. In all fairness to the hp rating, 85 was bigger than was available in 1958 as a single, so that hull was never tested with anything bigger. A good running 85 prop shaft hp could push your hull, if straight in the upper 40's maybe 50 mph.
My top pick if you are not worried about matching years would be a recent 4 stroke 50 hp, or 60 hp as a max. Top speed could be 35 with the 50 hp, if your bottom is good and about 9/10 mpg at best cruise of 20/25.
Many of your boat were most likely orginaly powered with a single OMC 35 and did fine, which means for equal performance a Merc 25 4 stroke would work and give tops speeds in the low 20's, and give 10 mpg plus.
If you bottom is not staight anything over 20 mph could a handful to drive.
The best solution would be to try several engine sizes to find the one that feels best, just hook up the sreering and manualy work the gas by hand at the engine to see how your hull reacts to power, takes two but might be worth the experiment. A tiller arm 25 to 40 could be a good place to start.
My 1960 Cruiser's 16' 202 runs easy 23/24 and tops at 28 with a 1960 Evinrude 40, does easy 35 and has a 40 hp top with my 1960 75 hp. As most of my running is at 20 or less the 40 works best for me.