In comparison to modern motors...

[tonynoriega2]

I have an Evinrude Aquasonic Fleetwin 7.5hp Outboard...

In comparison to its overall design, weight, HP output and so forth.... what is that type of motor comparable to now a days?

Could a 5HP modern motor power my boat just as easily?

Powering a 16' Alumacraft.

Just wondering if it is going to be worth the time and effort to keep it up and running versus looking at something newer.

thx

 

[RogersJetboat454]

Re: In comparison to modern motors...

Any of these old motors are worth the time and effort to keep running....

But to answer your question directly; your old fleetwin was most likely rated 7.5hp at the powerhead. Newer motors are HP rated at the prop shaft. Since the rating of your fleetwin didn't take into account the parasitic loss of power needed to spin the foot, in reality it would be more likely to perform more like a modern 5 HP engine.

 

[bbstacker1]

Re: In comparison to modern motors...

Tony, I think you have a couple of issues to consider. First the old motors like that one are great, very easy to work on, parts are readily available and they run so smooth. Reliability is not an issue, if the old motor is setup right you don't have to worry about it quitting on you.

I know personally (I have three of the old 7.5's, 1-Evinrude & 2-Johnson's) that they run about the same maybe a little less than a 87 Johnson 6 hp that I had. The newer motor turns more RPM's than the old ones so it pushes a touch better. The key here being a motor new enough to be prop rated HP which was around 84 or so.

If you decide to go newer and you are looking for something in the 6 hp range I would hold out until I found something that is a two cylinder. In used anything two stroke from 6 hp up should be at least equal to your old 7.5 (just remember new enough to be prop rated hp) a Johnson/Evinrude or Yamaha would be ideal (the Mercury's are good motor's just heavy in that hp range, mid 80's up). If you look new, all your options are four stroke only and I think everything under 8 hp are one cylinder. Just think paint shaker for one cylinders, they vibrate, especially at certain RPM's and they are expensive, however they are cheap to run.

 

[JB]

Re: In comparison to modern motors...

The Suzuki made JohnnyRude 8, 9.9 and 15HP 4 stroke twins from the late '90s are very smooth runners. My Johnny 9.9 was a delight on a small (Boston Whaler Tender 11) boat.

 

[nwcove]

Re: In comparison to modern motors...

Any of these old motors are worth the time and effort to keep running....

But to answer your question directly; your old fleetwin was most likely rated 7.5hp at the powerhead. Newer motors are HP rated at the prop shaft. Since the rating of your fleetwin didn't take into account the parasitic loss of power needed to spin the foot, in reality it would be more likely to perform more like a modern 5 HP engine.

++1^ on the fact that its well worth the bit of time and effort to keep the fleetwin in service, and we can debate its performance vs modern counterparts all day......but what is being forgotten is the cool factor, no motors made today come close to having the same styling as those johny rudes from the 50's!! jmo