power diff between '75 OMC 25hp and '96 OMC 15hp?

[jspringator]

Will I be able to notice the power difference between my 1975 'Rude 25hp and a 1996 15hp 'Rude? Lighter (10 lbs), newer and presumably more reliable. Something on the 25hp failed every day last vacation. Should I just keep what I have and work the bugs out of it?

 

[Whoopbass]

Re: power diff between '75 OMC 25hp and '96 OMC 15hp?

Your 25 should have more power then the 15 unless it's worn out.

I have a 1980 25 hp Johnson. I've owned it for about 15 years. It has never let me down and I run it pretty hard. Easy to work on and parts are fairly reasonable.

I recently had a 9.9 hp Evinrude. Never did run it so I don't know what kind of power it had. I did remove the carburetor to clean it out and it was a royal pain in the butt to remove compared to any of the pre 90's motors. The carbs are built way cheaper on the newer motors. The plastic outboard housing is alot cheaper made as well. The 9.9 started alot easier and idled real smooth. Looked good and I assume it was reliable.

My 25 weighs 110 lbs. The 15 weighed 80 lbs.

See if the guy will let you run it on your boat before you buy.
If your outboard runs and looks decent you should be able to get around $500 for it. I wouldn't pay anymore then a $1000 for the 15.

You can also find a clean 80's something OMC 25 and buy it then sell your outboard so your not out that much money.

 

[JB]

Re: power diff between '75 OMC 25hp and '96 OMC 15hp?

The 25 probably has about 5HP more than the 15, but, more important, it has more cubic inches, which translate into better slow and medium speed performance.

I would keep the 25 and get her working right.

 

[jspringator]

Re: power diff between '75 OMC 25hp and '96 OMC 15hp?

My 25 weighs 85 lbs. Thats why I bought it.

 

[wbeaton]

Re: power diff between '75 OMC 25hp and '96 OMC 15hp?

You will notice a huge difference. I have a run 15, 20, 25 and 30 hp (1980-90's) on my boat and there is a noticeable difference in power from the 20 hp and up over the 15 hp. Even my 1953 Evinrude 25 hp had slightly more power on my boat than my 1987 Johnson 20 hp, but that's probably due to the prop.

 

[BF]

Re: power diff between '75 OMC 25hp and '96 OMC 15hp?

I've got both an '82 15 hp and a 1970 (22 ci) 25 hp. With a nearly empty load (just me and light tackle) in a bare bones 16' utility boat, there isn't much to call between the two speed wise. 25 might be a mph or two faster. The real difference is when you get more of a load in the boat. There's a noticable difference when you have 2 adults in the boat... and if you've got even a heavier load... 3 adults and a dog the 25 is mucho better. It has more torque and hp to move the load. Having said that, the 15 idles right down smoothly, is quiet so is mucho preferable for trolling. Most times I used my 25 and kept a 6 hp on the back for trolling (and as backup). Just a month or so ago I bought a new 25 hp 4-stroke. I'm hoping that gives me the best of both worlds. We'll see.

At least that's my experience... your mileage may vary.

 

[Chinewalker]

Re: power diff between '75 OMC 25hp and '96 OMC 15hp?

In my experience, a motor that breaks down frequently is either suffering from tinkeritis or is simply worn out. "Tinkeritis" would be that it has been "repaired" by folks who are working without manuals, generally well-meaning folks who really don't know the proper way to repair the motor... A motor that is essentially healthy (good compression, spark & fuel delivery) should stay that way with proper maintenance and repairs when needed...

- Scott

 

[jspringator]

Re: power diff between '75 OMC 25hp and '96 OMC 15hp?

I'm afraid the "tinkeritis" culprit was me. I put a nut on the wrong side of the throttle stop screw, which caused most of my difficulties. I still don't understand that one, but my mechanic assures me it is now running fine. The plastic piece connecting the timing linkage and the throttle broke, which wasn't my fault. I'm getting all the plastic pieces replaced. Sometimes there is a learining curve with anything new. It usually starts pretty good, but it is definately a "2 hander while standing up" motor. I'm going to give it another try.