1967 Johnson 9.5 Cavitation Plate Hole

[superflydudebike]

I just purchased a 1967 9.5 Johnson. I noticed that it has a vent/weep hole on the underside of cavitation plate. At least that is what I think this is. It seems like a gas mixture is coming out of it (unburned gas?). I have a 1970 6 hp Evinrude and it seems to have this same hole in same location, except someone has taken it upon themselves to seal it. Should it be sealed? The sealed motor runs fine. This hole is on the left side of plate as you are operating motor. Cause for concern? What is the hole for? Why would anyone seal this up? Should I unseal it? Thanks.

 

[rudedude]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

The hole is so water drains out from the voids in the lower unit around the water pump. As for the fuel and oil you may have a small exaust leak or it is comming from above and draining into the leg.

 

[F_R]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

Above that hole is the exhaust outlet area. All two-strokes discharge some fuel/oil out the exhaust. So unless it is excessive, and it runs OK, don't give it a second thought. But do keep a check your gear oil in the lower unit. You should do that anyway. And don't plug it up. If it wasn't supposed to be there they wouldn't have spent the money to drill it.

 

[Evinrude Boater]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

The next time you service the water pump you'll see the hole drains a void in the casting. Water has to drain completely from the engine and this hole allows the water to drain from this flat section of the engine.

 

[superflydudebike]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

It was plugged up on my 6 HP Evinrude by a previous owner. I did not notice it until after purchase. I thought it was a repair job. For what possible reason would someone plug it up? It looks like some sort of epoxy material was smeared over area. Any ideas on how to remove this w/o wrecking surrounding paint? I should remove it, correct?. By the way, I had an Eska before the Johhnyrudes and I'm hooked now.

 

[wbeaton]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

Don't ask me why anyone would fill those holes, but I see it all the time. You don't have to remove all the old epoxy, but you should at least restore drainage. If you can see the old hole perhaps you could just redrill it. I don't know how you can remove the old epoxy. If water sits in there and freezes it could cause some damage.

 

[superflydudebike]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

Thanks for the help. I was thinking about that too - just locating the hole and opening it and leave the surrounding area alone. I'm glad to know that it was not a repair job.

 

[rudedude]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

Most reasons for people to plug the holes is that they have never seen it drain before and think it should not be there, " the other owner must had done that" Now the reason they never seen it drain before is because when the water pump houseing gets its little hole pluged they never see any drainage when useing muffs, and by the time they get the boat on the trailer after use and go back to check and tie down the boat the little hole has done its job and they dont see water comming out of there.


I just replaced my pump on my 125 Force and when I put the muffs on to check the new install I noticed the drain holes running water out of them, I posted that I had never seen this and was informed by Frank it was supposed to do that. I started looking at my old houseing and there was the tiny hole in the pump houseing that was pluged up.

I'am one of them that need to know the reason for everything.

 

[superflydudebike]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

Same motor, different concern. This 9.5 seems much more gas thirsty than my 6 hp. I took the wife and two kids for about an hour spin around the lake yesterday (largely full throttle) and I would estimate that it sucked up about two gallons of gas. Does that seem reasonable?. A six gallon tank of gas would last a really long time with my 6 hp engine. It seems to be running good, so I really don't want to mess with the lean/rich knob as it is set pretty lean already (it was too rich at first and I adjusted it).

 

[Harker]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

I think the rule of thumb for gas usage is 10% of HP per hour at WOT. If I am correct that would mean yours should use .95 gph.

 

[wbeaton]

Re: 1967 Johnson 9.5 Cavitation Plate Hole

Your fuel consumption sounds reasonable to me, superflydudebike.

 

[superflydudebike]

Re: 1967 Johnson 9.5 reasonable asking price

Re: 1967 Johnson 9.5 reasonable asking price

I'm looking to sell my 9.5. It is in good condtion. No work needed. Runs decent. What is a reasonable asking price? The only thing that would detract from the value is that is the engine cover has been painted by a previous owner a very light green. Duck hunting? All Johnson emblems are off of hood. The rest of it has original paint. I live in Wisconsin and this is a freshwater motor. I'm selling it because I have two slightly newer motors (6 and 15 hp) and I heard that parts for these motors are becoming hard to find.

 

[wbeaton]

Re: 1967 Johnson 9.5 reasonable asking price

Re: 1967 Johnson 9.5 reasonable asking price

Its hard to say without a photo. Maybe $250-400 if it runs well. Or make it look pretty and sell it for $400-500 (where I am).