Older Evinrude 20HP vs 15HP 2-strokes

[Tim Murphy]

Dear Board,

I have an older Smokercraft 165 tiller steer boat. It currently has a 1982 Evinrude 35HP on it that runs just fine. My problem is that several of the lakes nearby to me are restricted to 20HP maximum. For the short term I will probably keep the 35HP mostly because I plan to use the boat on larger lakes and some saltwater bays in the future.

I have my eyes on a 1993 Evinrude 15HP and a 1987 Evinrude 20HP and I'm trying to decide between the two. Price wise the 15 is a few bucks less but it's not less expensive enough to make the choice a no-brainer. I'm trying to get some idea of whether the extra 5 horsepower will make any difference when the largest lake I'll be using the motor on is less than 1500 acres? Most times I'll be putting in at any of several ramps and running from cove to cove to bass fish. A two or three mile run would be average and I might run as far as 8 or 10 on occassion but I prefer to trailer a bit further and spend time fishing. At times I will be doing some trolling for pike and walleye but I figure any of the motors will able to handle the trolling part.

Can anyone offer me any words of wisdom, should I pay the extra money for the 20 or can I get by with the 15?

Thanks in advance,

Tim Murphy

 

[Johny25]

Get the 20hp. The extra 5hp can make a significant difference when your talking smaller motors. Think about it, 25% more power. And on a 16' boat the extra 5hp could be the difference between planing and not planing.

The 87' 20hp is prop rated and can be made into a 25 or 30hp really easily and you will still have the 20hp badging and 20hp serial and welch plug number

 

[jasper60103]

Get the 20hp. The extra 5hp can make a significant difference when your talking smaller motors. Think about it, 25% more power. And on a 16' boat the extra 5hp could be the difference between planing and not planing.

The 87' 20hp is prop rated and can be made into a 25 or 30hp really easily and you will still have the 20hp badging and 20hp serial and welch plug number

+1^^.
Especially since you plan to run several miles.

 

[Tim Murphy]

Dear Johny and Jasper,

I was leaning towards the 20HP and you have helped seal the deal. I'm hoping the 20 will move the boat well enough so that I can just stick with it all the time and sell the 35HP.

When I was much younger my father and brother and a neighbor would go to Canada fishing. We rented a big heavy 16 foot fiberglass boat that was powered by a 20HP engine. It always got us out and back from the lodge on less than 9 gallons of gas no matter how far we roamed. That boat with 2 adults and two big young teenagers plus gear and food and drinks was probably fairly close in gross weight to my current rig with myself and my girlfriend in it. It always seemed to be adequately powered for what we were doing with it.

Like I said if I'm fishing what I consider to be a larger lake I'd rather trailer the boat 10 more miles than put in and run the ten miles. I have no desire to travel very fast on the water, I'd rather have reliability and decent fuel economy than speed. I'm not against leaving the house a little earlier and driving a little farther to the launch on a larger lake. You can cover ground faster at 60 MPH than you can at 20 - 25 MPH every day of the week.

Johny this last question is for you. Do you think I could use the carb and manifold off of my current 1982 Evinrude 35 to turn the 20 I am buying into a 30HP motor? When comparing the models on line it seemed to me that they use essentially the same engine blocks and gear cases. The same prop options are listed across the board for all the late 1970's through mid 1980's Evinrude 2 cylinders and the published weights of the two motors are within a few poundsof each other. I was hoping I could just swap engine cowlings, but my 35 has a white cowling with a light blue lower engine and the 20 I am looking at is the Evinrude silver/grey color so that won't work. If I can make a 30 HP I probably do that.

Thanks again,

Tim Murphy

 

[Johny25]

I don't think the cowlings will match up. If I remember correct the 87' lower cover will be narrower than the 82' top cover. As for the carburetor, the difference in the two would be the 82' is a choke style carb and the 87' is the primer style. With a little ingenuity it can be done though.

To make the 87' 20hp into a 25 I believe all that has to be done is bore out the intake manifold hole to match the back side of the carb where it mounts to the manifold. The intake was just restricted to get it down to 20hp. I know in 85' that is how they got the 20 and I am pretty sure 87' was the same. Remember throwing the 35hp carb on there will not get you to a 30hp. You have to get the larger intake to accommodate the extra fuel being thrown into the crankcase. More fuel + more air= More HP