1974 70hp Johnson vs 1973 85hp Johnson

[DMAN1968]

Hello,

Given the option to get either of these engines for around the same money and in the same general good condition...Which would you prefer?

I had read somewhere that the 1973 85hp was "underated" in respect to its horsepower. Is that true?

I'm looking to put it on my 24 foot Lowe party barge and was curious which one you folks thought would be better.

Thanks

 

[JB]

Re: 1974 70hp Johnson vs 1973 85hp Johnson

A triple looper vs. a crossflow gas hog? No brainer. The 70.

 

[JasonB]

Re: 1974 70hp Johnson vs 1973 85hp Johnson

I own a '76 85, which is identical to the '74. A friend had a '76 70hp on a similar hull to mine. Had his been set up properly, he probably could have run with me. As it was, i could run 37, he could run about 32. This was on 15/16' tri-hulls. His was not set up right though. Prop was way too deep and he didn't have a decent prop. JB is right, that 3cyl burned about 2/3 or slightly less than what I did in a day. On an average day, I could connect a fresh 6gal tank and run about 10-12miles at mostly WOT. He could follow me and still have a gallon or two left. He sold it for a little of nothing and I wish I had been able to buy it from him. Both are strong, excellent motors though and both have stood the test of time. You won't be dissappointed in either. If your boat is heavier, the pure grunt of the V4 is nice, but the 3cyl doesn't lag that far behind. I would guess that on a dyno, there isn't as much hp difference as the number on the hood suggests. With proper maintenance, both are likely to last most of a lifetime.

Edit: just saw that you are putting it on a pontoon. I suspect the 70 to be a near perfect motor, but the 85 would be just fine too. maybe a couple mph difference at most. If condition is equal, I would lean heavily to the 70.

 

[Texasmark]

Re: 1974 70hp Johnson vs 1973 85hp Johnson

10-4 on the looper.

I had a '72 125 on a 17+ ft Caravelle tri-hull with a pretty good V but was still classified as a tri-hull.

Friend had a 16' Kingfisher bass boat which was similar to the Ranger of the day, basically a flat bottom boat, with a 65hp Johnny.

We were fishing one day and I had 3 people in my boat, he was alone. I could barely walk away from him so I'd estimate he was doing about 37.

The V4's of that day were not loopers, but they did incorporate fuel efficient things to help the economy, carbs, exhaust tuning, streamlined lower unit, CD ignition......not a fuel sucking Fat 50, but not a looper either.

Had other friends with 85's which were stout engines.

For their size, both engines were running dudes.

Mark

 

[jimmbo]

Re: 1974 70hp Johnson vs 1973 85hp Johnson

The 70 has 49.7 cubic inches of displacment, the 85 92.6 cubic inches. This will provide much greater torque and under a heavy load the 85 will have much better performance. Having driven the same boat( 15' tri hull ) with both engines I found a marked difference in accelleration and about 3 - 4 mph in top speed.