1968 Johnson 65 hp v4 - water pump question.

GLPmike · Mar 7, 2010

Well got the beast running today in a small barrel of water.

Question:How soon should I see water exit after the motor is started and running at idle?

The motor started and ran solid for 5 mins. Had quite a bit of exhaust coming out of the tub while submerged. But, I was getting exhaust/steam from the water exit at the back of the motor. I did not see any water coming from the exit even after 5 mins of run time. The motor was starting to run hot as it started to smoke a little and I shut it down.

I installed an entire water pump kit but I am getting some oil leaking in to the tub. I replaced the bearing cap seal but I did not changeout the shift rod bushing/seal. Looks like I will take it apart next weekend and replace the bushing as well.

GLPmike · Mar 7, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Also, I noticed before attaching the unit that when I used a compressor to blow all the dust and dirt off the motor I blew air threw both ends of the copper pipe. These are the water pipes that attach to the lower unit and water pump. Some crap came out when I blew air in but the air coming out of the other pipe was much less than what was blown in. Is this normal or does my motor have a clog in the pipes?

a70eliminator · Mar 7, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

The water level in your barrel has to be about half way up the leg for it to pump water, if you put your hand in front of the upper exhaust outlet you should feel water spray mixed with the exhaust and your hand should get wet, you motor doesn't have a tell tale pee hole.

GLPmike · Mar 7, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Thanks.

I was only using a small barrel and the water level was only a foot above the top of the prop.

I thought the water intake was behind the prop?

By running it for five mins. did I possibly damage the motor?

So, was steam or exhaust coming out of the rear water exit?

Evinrude Boater · Mar 10, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

You're right, the water inlet is above the prop but the water level has to be above the water pump bulge in the case. See the photo. The pump doesn't self prime (it won't suck), it has to fill up with water flowing naturally into it before it will pump. Cooling water goes up the copper tube and through a small hole in the adapter plate below the engine block. You won't feel the same air pressure coming out as going in.
Exhaust will come out of the rear hole above the water line mixed with water.
You likely melted the water pump impeller running it dry for more than 10 seconds.

GLPmike · Mar 11, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Just pulled it apart and checked the impeller. Some wear, but it's fine. Apparently we got enough water in there to keep it from melting.

I just received the seal kit in the mail. So now we will putting this together for good (this season anyway) and will test in a deeper barrel.

Thanks

Evinrude Boater · Mar 11, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

GLPmike said:
I just received the seal kit in the mail. So now we will putting this together for good (this season anyway) and will test in a deeper barrel.

Are you concerned that the oil in the test tank is from the gear case? If it leaks it's more likely that you have water in the gear case since the pressure of the water forces into the gear case rather than the oil leaking out. Those old motors don't run efficiently especially at an idle. It's likely fuel being blown out the exhaust. They have an oil dump line which drains excess fuel out of the intake manifold. When they're not tuned properly they'll spew more fuel idling than a 5hp will use all season.
New seals can't hurt though.

GLPmike · Mar 12, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Yes. I am concerned and that's why we decided to replace all the seals.

As far as tuneup, we replaced most of the ignition system, including plugs, wires, points, distributer, rotor, etc..

If you have further suggestions on reducing oil/fuel loss.

Thanks

Willyclay · Mar 12, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Evinrude Boater said:
You're right, the water inlet is above the prop but the water level has to be above the water pump bulge in the case. See the photo.

I adapted a reverse water inlet (by-pass cover) for a flushing attachment with a piece of copper tubing and some JB Weld. This let me avoid using a barrel for testing/flushing. FYI, I also bungeed a piece of rubber over the forward water inlet while on the hose to help keep maximum water flow through the motor. Glad to hear you got it running. Good luck!

Evinrude Boater · Mar 12, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

GLPmike said:
If you have further suggestions on reducing oil/fuel loss.
Thanks

Check the oil in the gear case, if it's creamy white it has water mixed in it. If it's still golden yellow then the gear case is tightly sealed.
You can't do much about the raw unburned fuel that the motor blows out. They're just not efficient fuel burners. Think about how fuel efficient cars were back then. Boats were worse. Mine was running on two cylinders in a barrel and the top of the water was black with fuel in minutes. Keep it tuned properly and avoid idling. You can use synthetic oils if you desire to be easier on the environment. Given the age of the motor, I don't know that the limited improvement will justify the extra cost. I tried that once using the Evinrude oil and didn't notice a difference.

GLPmike · Mar 14, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Well. We installed the new seal kit, reinstalled the water pump and gaskets, used all the correct grease, gasket glue and gear case sealer.

The miter ran strong and is pumping a fair amount of water, so the pump looks good. Considering the other stories I have read we are not leaking much oil afterall after all the corrections noted above. When we pulled the motor from the barrel, we noticed an oil/water mixture coming from one of the weep holes located above the lower unit bolt closest to the boat. It was golden yellow in color. Also, not as much oil in the barrel as the first time.

We are using evenrude gear case oil.

On anothe note we are getting quite a bit of exhaust coming form the exhaust port near the prop. What is considered normal?

I did squirt some oil in the cylinders a couple of months ago when we started the project, but the motor has only been run for 15 mins since.

Thanks

Evinrude Boater · Mar 14, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

There are a number of small drain holes on the lower unit that drain cavities within the exhaust housing and the top of the gear case. That's why you store a motor vertical during the winter so that these cavities drain. Excess fuel that's dumped in the exhaust can mix with water and drain out of there but it's usually black ooze. Give it a good fast run and that will burn off any excess oil.
The exhaust does come out above the prop. If you tip the motor up you can look straight up the exhaust tube from there. Don't spray too much water up there if you're flushing the motor because it can go right up to the engine block and get into the cylinders that are open at the exhaust ports.

GLPmike · Mar 14, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Thanks.

Before we installed the lower unit I ran a pressure test 10 psi to the gear case and we did have a small leak of air coming from the shift rod where it enters the bushing. We did install a new o-ring on the bottom side of the bushing. But, we did not replace the shift rod bushing.

Will this be a problem? I have not sampled the gear case oil after today's test run in the barrel. I will check it next over the next few days.

I will post a picture of the motor running showing the white smoke coming from the exhaust as well.

Thanks again

a70eliminator · Mar 14, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

When running the motor in a barrel you'll have an oily mess every time even with a motor in good tune, just the nature of a two stroke.
Don't worry about the oil oozing from the crancase drains getting on the prop ect, there is also one towards the back that will ooze oil snot completely normal.

GLPmike · Mar 14, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Thanks. That's good to know. I spent the last two Saturday mornings taking the lower unit apart and reinstalling it and its time to move on to another part of the project.

Too much smoke?

a70eliminator · Mar 14, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

They tend to load up like that in test barrel, the smoke should clear up once you get it on a lake and run it at 50:1 oil mix.

GLPmike · Mar 15, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

Thanks. Can't wait to take it out for a run in early May. What type of updates should we make to the fuel system before we take it out for our first run?

Also, since we replaced most of the ignition system, what type of adjustments should be made? Timing, fine tuning?

Thanks

Evinrude Boater · Mar 19, 2010

Re: 1968 Johnson 65 hp v4 - water pump question.

I've never seen my motors smoke that much even when using 25:1 mixture. I hope it clears up after running it on the water. Run it wide open for a few minutes and pull the plugs to see how they look. See if they're a nice tan color and uniform. I think that motor has dual points so if 1 & 3 are different from 2 & 4 you might look at re-adjusting one set of points.
Updates to the fuel system? What were you thinking of? Make sure the fuel lines are in good condition and not leaking. Replacing with alcohol resistant fuel lines is a good update due to ethanol blended fuels these days. Also, mix the new marine fuel stabilizer with the fuel to help avoid moisture problems attributed to ethanol.
If you replaced ignition parts you should check the timing and perform the carb linkage synchronization (link & sync).

Bowrider-52 · Jul 14, 2011

Re: 1968 Johnson 65 hp v4 - water pump question.

Your thermostat may be sticking closed, that was the problem I had with mine.

GLPmike said:
Well got the beast running today in a small barrel of water.

Question:How soon should I see water exit after the motor is started and running at idle?

The motor started and ran solid for 5 mins. Had quite a bit of exhaust coming out of the tub while submerged. But, I was getting exhaust/steam from the water exit at the back of the motor. I did not see any water coming from the exit even after 5 mins of run time. The motor was starting to run hot as it started to smoke a little and I shut it down.

I installed an entire water pump kit but I am getting some oil leaking in to the tub. I replaced the bearing cap seal but I did not changeout the shift rod bushing/seal. Looks like I will take it apart next weekend and replace the bushing as well.

Pjbracke · Apr 22, 2012

Re: 1968 Johnson 65 hp v4 - water pump question.

How do you adjust the timing on these engines? And how do you synchronize the carb.

1968 Johnson 65 hp v4 - water pump question.

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