1968 evinrude 6hp top speed 6mph?

[ondarvr]

Unless plugs are fouled and not working, changing them rarely does much, but there is a placebo effect.

​Normally a good cleaning and re-gapping will let you know if they contributed to the problem.

 

[Scott Danforth]

Have you checked compression

 

[tpenfield]

I get about 13 mph with no gear on my 8.5 foot dinghy and Merc 7.5

The same boat with a 4 hp Johnson and no gear does about 5-6 mph . . .

So, 6 HP and gear may be what you are going to get, unless the cylinder drop test pans out.

 

[bspeth]

What elevation are you operating?

 

[Jessejba]

Hey guys, so i picked up an 82 mercury 7.5 that literally looks like someone bought it, took the water pump out, then set it in a corner. It's perfect. I got the water pump in today and I'll be going out with my son in the morning to swap it with the 68 6hp johnson. I'll let ya know how it goes.

 

[tpenfield]

:thumb:

I am at the finishing stages of rebuilding my 1969 Mercury 7.5 Great Motors those little Merc's IMO. you should see some better speed out if it. Hopefully all goes well.

 

[Jessejba]

Yea i picked it up for $60, cant complain for a brand new engine. Once it warms up a little we'll be heading out

 

[racerone]

Sometimes mistakes are made with new motors.----Then they are abandoned only to be re-discovered in " as new " condition

 

[Jessejba]

The motor runs perfect, the prop is pretty chewed up. It's the stock 9x7 3 blade and it's probably around 7 3/4x7 now. I ordered a new 9x9 3 blade. Any thoughts?

 

[Jessejba]

Thing goinf from 7"to 9" i too much? I know the 2 blades are 9" pitch

 

[Tim Frank]

I'd have stayed with the stock size, but there is a prop forum in here....you'll get best answer in there.

 

[Jessejba]

Well, im pretty sure that part of the problem is that there was about 120lbs of water in between my deck&hull. I got that emptied out, pushed off from the bank, pulled the cord, and the recoil spring broke. So I'm waiting for a new one tomorrow

 

[Jessejba]

I'm gonna stock with stock prop, but i go apt 12mph now

 

[oldboat1]

Oops. Water logged hull. Be curious to see what you get now with the 6hp (understood you to say you tried it with the Merc and damaged prop...)

If you have soaked floatation foam, you are obviously still carrying a bunch of extra weight. If you can open it up some, you might be able to drain and dry it some by storing it tilted, but will take a while. The permanent fix is to pull the floor and replace the foam, which is a big job.

 

[Jessejba]

There's no foam it's just chunk of Styrofoam in there. Next paycheck im going to fill it with the 2 parth closed cell foam ao that i dont have this problem again. And i figured it should help with rigidity and overall floatation

 

[oldboat1]

Well, lot's of know-how over in the hull repair forum. Good luck with it -- sounds like you've got a plan going.

 

[thatone123]

At that kind of price, why not buy a new one. At garage sales and etc. many fine old perfect running outboards can be found. There are many 40 years old or more that still have great compression and are built way better than the new ones. Older 9.5 OMC's for example have connecting rods 3 times the thickness of a newer Tohatsu 2 stroke. I can afford any motor I want, but yet run 70's/80's OMC small outboards mostly. 2 stroke power can not be beat and the quality of the engines is tops. JOHNSON You should last so long.

 

[Jessejba]

Im putting the johnson on my father's 12 ft flat bottom

 

[ondarvr]

At that kind of price, why not buy a new one. At garage sales and etc. many fine old perfect running outboards can be found. There are many 40 years old or more that still have great compression and are built way better than the new ones. Older 9.5 OMC's for example have connecting rods 3 times the thickness of a newer Tohatsu 2 stroke. I can afford any motor I want, but yet run 70's/80's OMC small outboards mostly. 2 stroke power can not be beat and the quality of the engines is tops. JOHNSON You should last so long.

Those old 9.5s aren't great motors, and most new motors are light years ahead of those old designs. While many of the old OMCs are pretty darn good for what they are, and fit into desirable niche, I'd go newer every time.

 

[ondarvr]

There's no foam it's just chunk of Styrofoam in there. Next paycheck im going to fill it with the 2 parth closed cell foam ao that i dont have this problem again. And i figured it should help with rigidity and overall floatation

Don't fill it with 2 part foam, it'll possibly create other issues long term, along with becoming waterlogged.