1969 9.5 Johnson Not Pumping Water

[BTF112989]

Hey everybody,
My 1969 9.5 Johnson is not pumping any water out of the telltale hole. One day it started and ran fine with a strong stream, and the next day nothing was coming out. I realized nothing was coming out after about 3 minutes of full throttle and shut it down immediately. I let it cool down and restarted it for 5 seconds to make sure I didn't lock the motor up.

Anyway, I pulled the lower unit, and the impeller looks like its in good shape. The only weird thing I noticed is that 2 of the 5 or 6 vanes on it were twisted the wrong direction, and it was very difficult to turn the driveshaft. I had to turn the propeller to turn the driveshaft. I took the impeller off and put it back in the housing correctly, then the driveshaft turned easily with just my hand.

When I screwed the 4 screws in the housing in completely, the difficulty turning the driveshaft occurred again. When I took the housing off the 2 vanes were facing the wrong way again?

I also put muffs on the lower unit and a hose on the telltale hole to flush any obstructions out, with no luck...

Do any of yall have ideas of what could be causing my motor to not pump any water out? Do you think its an impeller issue or possible the impeller housing? Or is the problem elsewhere?

Thank you to anyone who has a suggestion!


-Ben

 

[backyard mechanic]

Re: 1969 9.5 Johnson Not Pumping Water

So do I understand this right? You took the impeller out and it was twisted. You put it back and tightened it down only to find it twisted again? Strange!

Are you turning the drive shaft clockwise on assembly? Grease it up and put it back together but assure you turn the DS to the right. Note the prop rotation for reference. Assure all that prior to setting the pump housing on the impeller.

Sounds like maybe you're turning the DS or the Prop shaft the wrong way in assembly.

 

[bktheking]

Re: 1969 9.5 Johnson Not Pumping Water

It shouldn't matter , the vanes should flip in the direction of rotation. Put a new impeller in it, sounds like it may be weak.

 

[Rick.]

Re: 1969 9.5 Johnson Not Pumping Water

Sounds like the rubber has lost its set. Has it ever overheated? I would agree, put a new impeller in right away. Best of luck. Rick.

 

[BTF112989]

Re: 1969 9.5 Johnson Not Pumping Water

I am turning the impeller in the right direction. I made sure by looking at the prop rotation. Could the impeller housing be so old and rough/corroded(no corrosion was visible) that it is not allowing the impeller to spin when tightened down? The engine has never overheated before.

I also was reading somewhere that the thermostat could be preventing the water to be let out of the telltale hole. Could this be my problem? I think the thermostat is underneath the plate held on by 3 bolts on top of the engine block, correct? Only exhaust gas is coming out of the telltale hole, not even a mist of water.

My impeller rebounds to its original shape when out of the housing, and seems very strong. The engine has only been run 7 or 8 times since I replaced the impeller about 9 months ago, so I don't think the impeller is weak at all.

The engine was running great(other than not pumping water) and at full speed before I noticed no water was coming out, so the drive shaft and impeller had to be turning at that time if I was moving at full throttle. This leads me to believe that the impeller is functioning properly and it could be the thermostat.

 

[kenmyfam]

Re: 1969 9.5 Johnson Not Pumping Water

If some of the impeller vanes are flipping in the other direction then something is wrong. You should replace the impeller and check it out again.Possible you need to replace the entire pump housing. Photos would help.

 

[BTF112989]

Re: 1969 9.5 Johnson Not Pumping Water

Thanks for everybody's input! I replaced the impeller and housing, but that was not my problem. The engine still doesn't pump any water. I tried to force some water up through the pickup tube that goes into the impeller housing, but I couldn't get any to go through. I also tried to put a hose up to the tell-tale hole, and the water came out, but not through the pickup tube that goes into the impeller housing. Does anyone know what the best way is to flush the cooling channels out if I don't have access to compressed air? Could the thermostat also be malfunctioning and not allowing water to come through?

 

[kenmyfam]

Re: 1969 9.5 Johnson Not Pumping Water

Thanks for everybody's input! I replaced the impeller and housing, but that was not my problem. The engine still doesn't pump any water. I tried to force some water up through the pickup tube that goes into the impeller housing, but I couldn't get any to go through. I also tried to put a hose up to the tell-tale hole, and the water came out, but not through the pickup tube that goes into the impeller housing. Does anyone know what the best way is to flush the cooling channels out if I don't have access to compressed air? Could the thermostat also be malfunctioning and not allowing water to come through?

Take the thermostat out and check it over. Blast some water from the thermostat down through the system and water tube.

 

[F_R]

Re: 1969 9.5 Johnson Not Pumping Water

Take the thermostat out and check it over. Blast some water from the thermostat down through the system and water tube.

That hole in the rear is the exhaust relief. It just so happens that some of the cooling water exits there as a tell tale also. But you cannot flush water backwards through it. You might fill the cylinders up with water though, so stop doing that.

Also, you cannot run that motor on muffs.

The thermostat has a bypass that allows water to flow through part of the system even when closed. It probably is not the problem.

 

[kenmyfam]

Re: 1969 9.5 Johnson Not Pumping Water

That hole in the rear is the exhaust relief. It just so happens that some of the cooling water exits there as a tell tale also. But you cannot flush water backwards through it. You might fill the cylinders up with water though, so stop doing that.

Also, you cannot run that motor on muffs.

The thermostat has a bypass that allows water to flow through part of the system even when closed. It probably is not the problem.

I stand corrected. Did not realize that the thermostat cavity has a passage into the cylinders. Thought the cooling system water jackets and the cylinders were separate entities.

 

[F_R]

Re: 1969 9.5 Johnson Not Pumping Water

I stand corrected. Did not realize that the thermostat cavity has a passage into the cylinders. Thought the cooling system water jackets and the cylinders were separate entities.

Think about it--after going through the cooling system, virtually all outboards dump the cooling water into the exhaust. If that were not so, the exhaust would get red hot in no time. So if you stick a hose up the exhaust, water can go through backwards either way.

EDIT: kenmyfam, you did not suggest sticking a hose up the exhaust outlet, btf112989 said that's what he did.

 

[BTF112989]

Re: 1969 9.5 Johnson Not Pumping Water

Okay, I will stop doing that. Well, what is the best way to flush a blockage in the cooling system out on this motor then?

the driveshaft still seems to have difficulty spinning when I screw the housing down tight over the impeller(even with a new housing and impeller). It takes considerable effort to try and spin the driveshaft by hand. If I use the prop to help spin the driveshaft, it spins easier than by hand. It spins very easily with no impeller on it. I'm still wondering if this hard-to-turn drive shaft is making it hard for the motor to pump water while running. The drive shaft has to be spinning at the same speed as the engine all the time(even in neutral), doesn't it? And if it does, the engine always has to be pumping water(provided that there is no blockage).

Basically, I'm trying to figure out if the impeller is actually turning while the engine is running(the key is in the drive shaft and in the groove on the impeller), or if my problem is a blockage in the cooling passages, or if there is some other item i'm not thinking about.

 

[kenmyfam]

Re: 1969 9.5 Johnson Not Pumping Water

Don't know your motor that well but you could spin the drive shaft with the lower unit submerged and see if anything is getting from the water pump to begin with. use a cordless drill or similar to rotate the shaft.

 

[bktheking]

Re: 1969 9.5 Johnson Not Pumping Water

I saw a post on here where a guy fabricated a plate with a water fitting attached to it for flushing, he removed the flushing plate? on the left hand side of the lower unit and replaced it with the one he fabbed. The thermostat is under the 3 screw plate at the top of the head, pull it out and inspect/test, you could also force water down the head from here.

 

[jasper60103]

Re: 1969 9.5 Johnson Not Pumping Water

Don't know your motor that well but you could spin the drive shaft with the lower unit submerged and see if anything is getting from the water pump to begin with. use a cordless drill or similar to rotate the shaft.

Here's a good video of what kenmyfam is talking about...

http://www.youtube.com/watch?v=xAJfBKNs7bo

 

[kenmyfam]

Re: 1969 9.5 Johnson Not Pumping Water

Here's a good video of what kenmyfam is talking about...

http://www.youtube.com/watch?v=xAJfBKNs7bo

Nice link.

 

[BTF112989]

Re: 1969 9.5 Johnson Not Pumping Water

I checked the operation of the impeller using the advice and video link y'all gave me. The impeller turned out to be pumping water well! So I now know the impeller is not my problem.

So my next step was to check to see if there is some blockage in the system. I found some flexible tubing that fits around the pickup tube very well, so I attached it to the pickup tube and tried blowing some air from my lungs through. I couldn't get any air to go through. I then took the advice of the video that was posted and got my garden hose out to try and force some water through. I used the "heavy stream" setting on the hose nozzle and attached the tubing to the nozzle. When I turned the hose on, no water was able to work its way through the system either. NONE. I tried pulsing the water to push anything out of the water passages. That did not work either. So now I think that I either have a major blockage in the water passages or the thermostat is blocking all the water from going through. F_R said that the thermostat has a bypass valve, but no water is coming through.

I then thought I should take the thermostat out, and try to flush water down from there, but the plate would not come off. It looks like the thermostat cover plate has never been taken off of the engine. I tried cutting the seam that the paint was covering with a razor blade to make it easier for the cover to come off, but that did not help. I broke a small chunk of what looks like a metal gasket or part of the cover plate off, so I was scared to go any further. Any special techniques for getting this cover off without breaking it?

I'm thinking it has to be an issue with the thermostat, because nothing that large could really work its way up into the water passages based on the size of the intake grate near the prop and the water tube pickup size.

How do y'all think I should go about clearing this blockage or getting to the thermostat?

 

[bktheking]

Re: 1969 9.5 Johnson Not Pumping Water

Did you get the bolts out of the thermostat housing? I'm assuming you did, if you did- spray penetrating oil around the housing and into the bolt threads, take a flathead screwdriver or thin chisel and tap it into the gasket area, go around the diameter of the housing, it's glued to the head from years of not being removed and needs to be coaxed off, it will with time and patience.

 

[BTF112989]

Re: 1969 9.5 Johnson Not Pumping Water

Yes, I got all three bolts out. I have it soaking in penetrating oil as we speak. Does it have a metal gasket? (thats what it looked like)

Do you think the thermostat could have failed and caused the passage to be completely blocked?

 

[kenmyfam]

Re: 1969 9.5 Johnson Not Pumping Water

Yes, I got all three bolts out. I have it soaking in penetrating oil as we speak. Does it have a metal gasket? (thats what it looked like)

Do you think the thermostat could have failed and caused the passage to be completely blocked?

Anything is possible if the stat has been in there for many a year.
Be gentle, it will come off