1972 18HP Evinrude vs 1972 25HP Johnson

[Cap'n Chaos]

I'm wondering if there would be a profound difference in performance between the two motors?

This would be pushing an '05 Alumacraft 14/42 rated for max 25HP.

[F_R]

A few miles an hour faster. Depends on the load you are carrying. Is that a jon boat?

[steelespike]

The 18 could make about 27 a 25 about 32. Actual figures may vary but the spread would be about the same. Where the 25 would shine is as you add weight.
These are the same powerhead and approximate same weight about 81 lbs.
The 25 is rated at 6.000 rpm.Todays 25 are about 140lbs.

[Cap'n Chaos]

F_R - yes she's a Jon Boat, no console, two bench seats... very simple and basic, just what I wanted.

steelspike - 25? 25mph?

That was my next question; regarding weight. I'm thinking a 2005 boat was probably engineered for a 4-stroke to push it.

I have a question about using a small 900W max generator in the boat... if I can ever get out to try flounder gigging that is. What would be the best forum to ask about this? (Saltwater fishing?)

I'm wondering about grounding the generator, wiring for lighting, if I need a small breaker panel etc. I've never been and know absolutely nothing about it, or how to safely run wiring for lighting, depth finder, etc in a wet environment. (I want to have fun and not get hurt or put anyone else in harms way doing so.)

[Cap'n Chaos]

Attachment 122023Attachment 122024

[steelespike]

If you read it again I think you will see:
As you asked a 18 will do about 27, a 25 will do about 32. Those speeds are for a reasonably fast boat. While the 15/42 is reasonably light I wouldn't call it fast with those 5 keels
but I'm sure it will do fine.

[F_R]

I have a 1436 14' Alumacraft jon boat, rated for 15hp max. That makes it six inches narrower than your 1442. The biggest I've had on it yet has been 12hp. I can't imagine wanting a 25 on it. In the first place it would rattle your brains out in anything higher than a 6 inch chop.

[Cap'n Chaos]

I had thought about putting my 6HP on it - that one pushes my 12' flatbottom along plenty fast even with a passenger... but I don't want to stress the motor.

I'll stick with the 18HP; the thought of 27mph/knots is fast to me, lol.

Thanks for the info!

[Texasmark]

Of course you want the 25 if BIA ratings allow it. If no rating plate put her on....just know your limits and respect them...there are times to have fun and times to be prudent.

Mark

[F_R]

The Bible says there is a time to die too.

[Texasmark]

The Bible says there is a time to die too.

Gimme a break!

[1946Zephyr]

Myself, personally wouldn't run anything bigger than a 15 on that. A 14' jon boat is a pretty light duty boat. Now a 14' fiberglass with a closed bow would be a nice match for that '72 25hp.