Poll - How quick do your old outboards push?

[wbeaton]

Performance of old outboards came up in another thread and I thought it might be interesting to see what others are getting for speed out of their old motors. I'm sure my numbers will seem quite small compared to the folks with sea-flees and race boats.

I run my kickers on a 1979 12.3' deep and wide Springbok aluminium utility boat max rated for 12.5 hp. Here are the top speeds according to my GPS rounded to the nearest kmh/mph.

1950's Johnson/Evinrudes

3 hp - 10kmh / 6mph (no planing)
7.5 hp - 15kmh / 10mph (no planing)
10 hp - 32kmh / 20mph
15 hp - 36kmh / 22mph
18 hp - 42kmh / 26mph

1981 Johnson 15 hp - 40 kmh / 25 mph

Test results on a 14.5' Springbok deep and wide aluminium hull with full floor max rated for 28 hp. This boat is heavy and requires a minimun of 20 hp to get two guys on plane.

1953 Evinrude Big Twin 25 hp on a 37 kmh / 23 mph.

On this boat the Big Twin performs slightly better than a 1987 Johnson 20 hp, about the as a 1983 Johnson 25 hp, and not as good as a 1988 Johnson 30 hp.

 

[steelespike]

Re: Poll - How quick do your old outboards push?

As I recall the early 18 hp manuals listed stock top speed of the 18 at 27 mph.I would say your 26 mph is respectable. It seems the 10 was rated at 21 mph.So your close there as well.
I was dissapointed your 7.5 didn't plane.Perhaps an extension handle would help.We used to easily plane a 5hp Gale on a 12' flat bottom steel boat with an extension.Of course a flat bottom usually gets up easier.

 

[wbeaton]

Re: Poll - How quick do your old outboards push?

Yeah, I was dissapointed by the 7.5 hp too. I have a couple of them and they would plane my other narrow 12' boat and run me up somewhere around 20 mph probably 17 mph as I think that was the rated speed. That boat was super tippy and only rated for 6 hp. With the new boat the 7.5 hp only plows the stern down no matter how I weight it. But that's fine. I have lots of 10 hp motors.

 

[jbjennings]

Re: Poll - How quick do your old outboards push?

very interesting thread.... i'm going to test my 57 johnson 18 today with my gps and see how fast she'll run. I don't think mine will come close to 26 mph but i think it has a lot of hours on it. my 7.5 evinrude from '55 is not that impressive on power either but it runs like a singer sewing machine. converted my 10 and 7.5 to single line fuel--- runs great. hope you get a lot of feedback on this one, i'm eager to see the results. by the way, my dad said in the '70s he had a johnson 25 with a special order 2-bladed prop that would dust 50 horses and blow 20hp mercurys out of the water (i always considered '70s 20 horse mercs as pretty darned fast). said it had a "roll" to it at wide open due to the high rpm's and the engine ran for years.
jbj

 

[baconbiscut]

Re: Poll - How quick do your old outboards push?

With my 1955 5.5 hp johnson my 14ft starcraft metal boat does 12.3 to 12.5 mph.

 

[hitace]

Re: Poll - How quick do your old outboards push?

hey wbeaton what kind of props were you using plastic aluminum 2 blade 3 blade

 

[Laddies]

Re: Poll - How quick do your old outboards push?

We have a couple 7.5HP mercs KG4s that run 40+ MPH and a Mark 20H thats 60+ MPH, Also a 45HP Mark 55H thats 65 MPH all are on utilty hulls

 

[wbeaton]

Re: Poll - How quick do your old outboards push?

All original aluminium props. Two/three blade on the 3 hp's, two blade on the 7.5 hp's and three blades on everything else.

Laddies, I would love to see a 7.5 hp go 40+ mph! Wouldn't want to drive it too badly, but I'd love to see it.

 

[hitace]

Re: Poll - How quick do your old outboards push?

yes i would love to see a 7.5 do 40+

 

[Bobobob]

Re: Poll - How quick do your old outboards push?

My motor isn't as old as yours but it's a '62 Johnson 40, I have it on a 13' 7" fiberglass closed bow Dart. I was able to get it up to 28 mph on my GPS, the boat is quite heavey and the floor is waterlogged, I believe the boat is as old as the motor.

 

[hitace]

Re: Poll - How quick do your old outboards push?

hey robandbob heres a nice boat for your 40 hp johnson

http://hydrostream.org/Specific Models/Voodoo.htm

 

[Bobobob]

Re: Poll - How quick do your old outboards push?

thats crazy, don't need that much speed.

 

[Laddies]

Re: Poll - How quick do your old outboards push?

Sorry double post

 

[Laddies]

Re: Poll - How quick do your old outboards push?

wbeaton, don't have many photos most of my stuff was vidio, but I posted a few photos out of the 1982 Top of Michigan Marathon Flyer and a couple pictures people sent us of my sons after they moved up to D stock thats 44 cu.in. or 45 HP I posted them on jbjennings tread "Hey Laddies" as he asked for photos and I didn'want to take up space here, Thanks Bob

 

[jbjennings]

Re: Poll - How quick do your old outboards push?

Just tested my '57 18hp johnson, left-handed model. It pushed my boat at 21.6 mph on my GPS. That was max speed with everthing positioned perfect in the boat. Not bad for a 50year old motor. See pic.

 

[hitace]

Re: Poll - How quick do your old outboards push?

on my 12 foot alum flat bottom boat with only me and with a 1952 10 hp johnson i was able to hit 23.5 until it sunk now it wont do half that i think its only running on one cylinder.

 

[Scaaty]

Re: Poll - How quick do your old outboards push?

yes i would love to see a 7.5 do 40+

Guess ya missed the old days of the Mark Mercs on Hydro's...

 

[Scaaty]

Re: Poll - How quick do your old outboards push?

wbeaton, don't have many photos most of my stuff was vidio, but I posted a few photos out of the 1982 Top of Michigan Marathon Flyer and a couple pictures people sent us of my sons after they moved up to D stock thats 44 cu.in. or 45 HP I posted them on jbjennings tread "Hey Laddies" as he asked for photos and I didn'want to take up space here, Thanks Bob

Well Bob, I have a couple pix...(thanks for the VHS tapes of the races again...still waiting for winter to hit and watch all the way)
Not sure on the first pic, but the second is Bob's (Laddies) son..

 

[wbeaton]

Re: Poll - How quick do your old outboards push?

How long is your boat, Jason? 22 mph sounds a little low.

My update...1954 Evinrude Super Fastwin 15 hp with a 8.5 x 8.5 prop hit 36kmh / 23 mph.

Nice pics, Scaaty.

 

[skimmer]

Re: Poll - How quick do your old outboards push?

I wish I knew I need a GPS, my speedo's been out of action not long after I put my old,ish 79 Mariner 30 on the back when I first took it out it read about 20-24 knots but it wasn't working very well and now it doesn't work at all, is that about right for a 30 on a 4 metre aluminium hull.