what size used / vintage outboard should I buy

[pfeffer]

I am in the process of restoring an 18 foot aluminum deep v runabout. It is a Lonestar Eldarado 18 and I am looking to put a 1970's era long-shaft Evinrude outboard on her. I am looking at used motors and I have the ability to purchase a 85 hp or a 135 hp from a trusted source. I will be boating on lake Michigan - doing some fishing, skiing and tubing with the family - what size engine should I purchase is the question I am asking? I am a sailboat guy and I have little practical knowledge of motor boating and I do not want to purchase something that I will outgrow. Kindly let me know your thoughts.

thanks! Adam

 

[Scott Danforth]

I would buy a 90's or newer. mid 80's is when they went from crank rating to prop rating and standardized the clamp mount

 

[Chris1956]

A V4 engine would be good on that boat. I would try to get the larger one. I think some years went up to 140HP.

 

[racerone]

A 1984 model 115 / 140 HP model Johnson or Evinrude would be a good choice.-----A simple and smooth running engine.----I assume you as a sailor would want to do your own work.

 

[pfeffer]

A V4 engine would be good on that boat. I would try to get the larger one. I think some years went up to 140HP.

what do you mean by a V4 engine? New to motorboats so sorry if I sound like an idiot.

 

[pfeffer]

A 1984 model 115 / 140 HP model Johnson or Evinrude would be a good choice.-----A simple and smooth running engine.----I assume you as a sailor would want to do your own work.

Yes I would like to get my hands dirty and be responsible for maintaining the outboard. Told that I should stick with Evenrude and Johnson by others and try to avoid older Mercs. I would love to find models in the 80's that are reasonably priced and I will keep looking. The big question is how big of an outboard can I put on an 18 foot boat? If I find an awsome 135 or 140 will I be way over powered? the boat is 18 feet long, with a 85" beam. The manufacturer is out of business and this thing was built in the late 50's or early 60's - thus no max hp rating plate on the boat.

 

[Scott Danforth]

use the HP calculations http://newboatbuilders.com/pages/33CFR_HP.html

assuming your transom is over 20" tall

(2 x Boat Length x Transom Width) - 90

so if your transom is 85" and over 20" tall, you can run a 160hp

if your transom is less than 20" tall

(0.8 x Boat Length x Transom Width) -25

that means you can run a 75hp

however if there was a capacity tag on the boat, I suggest you find out what it was rated at.

also, you have started multiple threads on the same subject. thats against the rule.

 

[racerone]

Your location has a lot to do with finding a suitable motor.-----Older motors are popular where one or more shops are willing to maintain them.-----That 18 footer should easily handle a big V-4.-----Perhaps apply for a rating plate for the boat.------Myself I prefer one of those motors in " as is " condition for less than $500, much less in some cases.-----Rebuild it and then you know what you have.

 

[jbcurt00]

Deleted the duplicate topic you started in the Resto forum as its a repeat of your 1st post in this topic.

refrain from duplicating topics.

if you want to start a topic about Resto/rehab of the boat itself, but oeave motor discussions here in the outboard forums.

 

[pfeffer]

use the HP calculations http://newboatbuilders.com/pages/33CFR_HP.html

assuming your transom is over 20" tall

(2 x Boat Length x Transom Width) - 90

so if your transom is 85" and over 20" tall, you can run a 160hp

if your transom is less than 20" tall

(0.8 x Boat Length x Transom Width) -25

that means you can run a 75hp

however if there was a capacity tag on the boat, I suggest you find out what it was rated at.

also, you have started multiple threads on the same subject. thats against the rule.

Cheesehead -thank you so much for providing these calculations - I plan on going out into the chicago cold tonight to measure the transom depth. Sorry for cross posting. New to motorboating and new to this site. I will do better in the future. FYI I am likely buying an outboard from Wisconsin and when I go there I always get myself a cold Spotted Cow beer and a plate of cheese curds.

 

[pfeffer]

Deleted the duplicate topic you started in the Resto forum as its a repeat of your 1st post in this topic.

refrain from duplicating topics.

if you want to start a topic about Resto/rehab of the boat itself, but oeave motor discussions here in the outboard forums.

sorry about that !!

 

[Scott Danforth]

Cheesehead -thank you so much for providing these calculations - I plan on going out into the chicago cold tonight to measure the transom depth. Sorry for cross posting. New to motorboating and new to this site. I will do better in the future. FYI I am likely buying an outboard from Wisconsin and when I go there I always get myself a cold Spotted Cow beer and a plate of cheese curds.

spotted cow is ok, however get some Door County Polka King

Plenty of mid 80's, mid 90's motors in WI cheap. just need to keep a look out. Most are still listed in the newspapers by their original owners.

 

[Chris1956]

Pfeffer, OB motors came in multiple cylinders, usually linked to HP, and loosely to year made. In general, smaller HP motors were inline 2 and 3 cylinders. Larger motors were V4 and V6 engines.

In the 70 and 80s motors as you prefer, Your boat could run on a 3 cylinder OB motor, but I think you would be happier with more HP.

A V4 engine made by Johnson/Evinrude is one of the best ever made. The best ones (IMO) came in HP from 90HP to 140HP. A standard 18 footer like you have ought to be able to handle any of those.

If you can find your way to buying a motor made in the 90's, and still want Johnson, the 60 degree V4 engines, up to 130HP were very good.

 

[racerone]

What year did they build / market a 60 degree 130 HP V-4 model ?

 

[pfeffer]

So after looking at the calculations on how to correctly size an outboard for my 18 foot boat with a 20 inch transom I can to the conclusion that more HP is better than less. Just purchased a 1973 Evinrude 135 hp with controls and installation.
https://m.facebook.com/story.php?story_fbid=430612467415067&id=390026894806958

 

[racerone]

The 73 models were not the best in my opinion.--------Not many parts from a 72 will fit and not many engine internal parts from a 74 model will fit !

 

[pfeffer]

Thanks for the feedback

 

[Chris1956]

My mistake, The 1998 130HP V4 was a 90* model. Sorry...