25 HP Differences, Need Somebody with Experience

[peterskeeter]

I have a 1975 Evinrude 25 HP Tiller which I have rebuilt recently, everything is new on this motor, including the prop. The motor is mounted on a 14ft Allweld Flat (Jon Boat for Northerners!). The boat does about 26 MPH wide open with one person and a light load. Motor runs flawless I must say but I feel as if I just need a little more power sometimes, as in when I take somebody else with me. Would a newer 25 HP rated at the prop be a major difference or should I stick with what I have? I do realize at this moment I have a glorified 18 HP. How much more speed can I expect with a newer model? Is it worth it? Thanks for the help and advice

 

[tashasdaddy]

Re: 25 HP Differences, Need Somebody with Experience

you have a good dependable motor that will run another 35 years. 26 mph, you are doing good for a flat nose boat. you can expect a drop in speed with the added load. i do not think the cost would be worth the increase in power.

 

[jbjennings]

Re: 25 HP Differences, Need Somebody with Experience

I feel qualified to answer this one........

Stick with what you have. My dad's 2007 or 2008 25hp 2-stroke yamaha gets 26.5 mph on gps with he and I and no gear on a 14' 36" duracraft john boat. You will not get more than 3 or 4 mph more with a newer motor. Less, in my opinion, with one of the newer 4 stroke motors due to their heavy weight and lower torque in comparison with the 2-stroke.
Your motor may perform better to your taste if you get a prop more suited to a load. I know I like to use one prop during duck season when I have a heavy load of hunters and gear, and a different one in fishing season when I'm either by myself or have my 8 yr. old son with me.
You will not find a better 25hp motor than a 25hp OMC from darned near any year model.
Use it, enjoy it, check into a spare prop. Powertech propellers in Shreveport, LA makes a nice prop, and reasonably priced.
JMO,
JBJ

 

[1946Zephyr]

Re: 25 HP Differences, Need Somebody with Experience

That model 25hp is actually the best model made. It is the old 22 cube design that was based on the old 18's and 20's. The most power for it's weight. The newer design, which came out in 1977, was a bit bigger and heavier than the older style like yours. I, myself have one of the later versions and it'll be interesting to see how it performs, but I bet it won't be as snappy as yours.

 

[Whoopbass]

Re: 25 HP Differences, Need Somebody with Experience

My 78' 25 Evinrude is 1-2 mph faster (GPS) then my 1987 25 Evinrude same boat/load.
The only difference appears to be the size in lower units. Maybe the small lower units are faster.

My 15' aluminum semi-v modified into a bass boat maintains about the same speed whether i'm alone or have someone with me. I'm getting the same speed your getting.

 

[peterskeeter]

Re: 25 HP Differences, Need Somebody with Experience

Thanks for all the input everybody. What I mean by "newer" is a motor rated at the prop with the larger displacement. If I changed motors, I would stay 2 cycle. I would either consider a newer OMC, YAMAHA, or SUZUKI late 90's model 25HP. It looks like the weight difference compared to what I have now would be a 10-15 lb increase. I'm just wondering how significant the performance gain would be with these engines. It seems like the newer models pack alot more punch than the older ones with the ratings at the head and the smaller displacement. I like my current motor, it idles great, cranks right up, and has been reliable since the rebuild, but it would be nice to have a little more pep in her step. Don't get me wrong, I will only part with this motor for a really good deal.

 

[blimp]

Re: 25 HP Differences, Need Somebody with Experience

a '85+ motor would have through hub exhuast and 31.8 cubic inches. I have one and it will push 30mph with just myself in a 14" simi-v alum. The modified exhaust design and and prop HP rating will give you a bit of a boost, but like others have said, the higher displacement comes with a price: weight. I can barely lift the ~130lb beast alone, that 25 you have now is likely the best power/weight ratio out there.