Johnson TD 20 no water flow to head even after Water Pump rebuild (Fixed, Bad Seal)

[mrtapes]

I just rebuilt the water pump (cleaned and installed new impeller) and carburetor on my old Johnson TD 20 and got it running this afternoon.
However it is having the same issue it had before I rebuilt the water pump, It's overheating badly.
I took the water pump apart again and also took the metal hose off the engine that connects to the head.
I can blow air from a compressor up the shaft from the propeller/water pump housing to the head and also blow air down the other tube to the exhaust exit.
Although I rebuilt the water pump, it appears no water is going to the head even though air flows freely up the pipe.
Any suggestions?
Thanks a lot.

[GTS225]

Perhaps things are plugged up on the suction side. I found that with a '59, 5.5 Johnson I got recently. The pickup screen wasn't bad, but the auxiliary inlet had a bunch of debris/sediment in it to the point it was blocking water flow. Take the narrow, rectangular side cover off the lower and check inside there.

Roger

[nwcove]

are you testing in a barrel? if so, try removing the prop so theres not so much turbulence. (be carefull not to over rev tho.

[wilde1j]

What was the condition of the wear plate and liner/housing? Any scoring and a new impeller won't help much.

[Mas]

Make sure the motor is in deep enough...well above the water pump. Also, is this a salt water motor? You could have restricted passages. When you remove the original impeller, was it intact...or chewed up? Bits of the original impeller could allow air....but not enough water to prime.

Mas

[mrtapes]

I was testing it in a barrel, so I guess the turbulence could be an issue. However it didn't appear that any water was reaching the upper unit at all. The metal tube that runs from the block to the return fitting was totally dry.
The original impeller was in decent condition, shape wise, it wasn't chewed up at all. The only thing that seems out of sorts in the water pump area is the rubber that is on the feed pipe is kind of gone. However it would seem to me that some water would go up the tube??
The motor was a salt water motor before I got it years ago. I've never done anything with it other than have it sit around for years after getting the magneto fixed. Maybe I need to tear the whole thing down and clean it up inside the block?
Here are some pictures of the motor in question:

TD20.jpgTD20-1.jpgTD20-2.jpg

[Mas]

If there is a water tube grommet that's missing or in bad shape...that is the issue!

Replace the grommet and see what you've got!

Mas

[mrtapes]

Where do I find one of those?
What does it look like so I could rebuild it?

Mine looked similar to this:td20johnson009.jpg
Maybe just a little more chewed up but not much.

[1946Zephyr]

You should be able to find one at Sea-Way Marine. It's called a water tube seal.

[mrtapes]

Seems to me that even if the tube seal thing was deteriorated that some water would go up the pipe. I mean, no water was going to the block, None.
What else could it be?

I just looked at a you-tube video of a TD20 running and there was water pissing out of the telltale like crazy. I have no water reaching that tube or elbow whatsoever.

[mrtapes]

What was the condition of the wear plate and liner/housing? Any scoring and a new impeller won't help much.

If the plate and housing have issues is there any help other than replacing the parts. Does this need to have a complete seal in order to get the water forced up the tube?
Maybe I could seal it with something?

[wilde1j]

Maybe magic?

If there's scoring, just replace the parts! Most of the 'water pump doesn't work' things here are due to the inexperienced thinking an impeller is the only thing needed. For most people w/o the experience to judge a reusable part, a complete pump is the only way to go.

[mrtapes]

Maybe magic?

If there's scoring, just replace the parts! Most of the 'water pump doesn't work' things here are due to the inexperienced thinking an impeller is the only thing needed. For most people w/o the experience to judge a reusable part, a complete pump is the only way to go.

That would basically mean replace the whole lower unit of the motor.
I had issues from the start with this thing because two of the three screws that hold the housing together were seized and I had to drill them out and re-tap the sockets.
In order to get the thing apart I had to pry in between with a screwdriver and the plate got ever so slightly bent, But only on the outer edge.
The rest of the plate looks fine and isn't scored where the impeller moves.

[nwcove]

mr tapes,(or others) in pick #2, there is a coat hanger sized piece of wire, where the tiller arm connects to the engine, it is some type of needle/seat arrangement, what exactly does that do? (i know i should have started a new thread, but the pic is perfect)

[wilde1j]

That would basically mean replace the whole lower unit of the motor.
I had issues from the start with this thing because two of the three screws that hold the housing together were seized and I had to drill them out and re-tap the sockets.
In order to get the thing apart I had to pry in between with a screwdriver and the plate got ever so slightly bent, But only on the outer edge.
The rest of the plate looks fine and isn't scored where the impeller moves.

No, not replace the whole lower unit, just the whole water pump. BTW, if you even slightly bent the wear plate, it won't pump. Also, the seal between the wear plate and housing needs to be near perfect, or again no pumping. You haven't said anything about the housing, so I assume it's pristine.

[jimbo_jwc]

The needle adjustment is for low speed idle runs fuel thru crankshaft to cylinders since we only have fwd &rev . I Own 2 of these my grandfathers 1949 and a newer one and only differences I;ve noticed was decals and motor mount .Have never replaced pump or anything except fix pull rope soldered in.

mr tapes,(or others) in pick #2, there is a coat hanger sized piece of wire, where the tiller arm connects to the engine, it is some type of needle/seat arrangement, what exactly does that do? (i know i should have started a new thread, but the pic is perfect)

[mrtapes]

No, not replace the whole lower unit, just the whole water pump. BTW, if you even slightly bent the wear plate, it won't pump. Also, the seal between the wear plate and housing needs to be near perfect, or again no pumping. You haven't said anything about the housing, so I assume it's pristine.

By whole water pump I assume you mean Wear plate and housing?
There isn't much else to this with the exception of the impeller and eccentric.
Any idea where I would find these parts if I was to try to replace them?
As far as I can tell the housing is fine but I'm no expert!
Couldn't I just try to seal the plate and housing with gasket material or sealant?

[wilde1j]

You could seal them with gasket sealer if they are in OK condition. Make sure none gets inside the housing. If this is a very old motor and the parts aren't good, you may need to try SeaWay Marine or another NOS dealer.

[nwcove]

have heard through others that you can replace that older style water pump with a more modern setup? (a bit of honing to get it to fit tho) is this the case for the td 20? hope it works for my tn 26. the "modern pump" might push more water.

[mrtapes]

You could seal them with gasket sealer if they are in OK condition. Make sure none gets inside the housing. If this is a very old motor and the parts aren't good, you may need to try SeaWay Marine or another NOS dealer.

It's a TD 20, they are all old! LOL
I know what you mean though, usage wise. I haven't a clue as to the usage other than the fact that it must have been used in salt water as I bought it in a shoreline town (New London, CT).
I really don't want to put money into this thing as I could just be chasing parts. I have a 1971 6HP Johnson 6R71 and a 1979 15 HP Johnson 15R79 so this thing is just a novelty motor for me.
I have done successful work, rebuilding the water and fuel pumps on both motors as well as the carburetor on the 15 and this TD 20. I'm going to rebuild the carburetor on the 6 HP soon.

So, I think I'll try sealing the plate to the housing and see how that works. As long as it pumps I don't care about the originality of the thing.

[Chinewalker]

No, not replace the whole lower unit, just the whole water pump. BTW, if you even slightly bent the wear plate, it won't pump. Also, the seal between the wear plate and housing needs to be near perfect, or again no pumping. You haven't said anything about the housing, so I assume it's pristine.

Wilde1j - this isn't a traditional waterpump assembly. It's a propshaft driven plunger style pump running on an eccentric. No wear plate... The housing is part of the lower unit...

[mrtapes]

I think I'll try sealing the plate to the housing and see how that works.

So, I decided I didn't want to go fishing for new parts to chase this solution and that I would try to seal the housing to the plate.
I had some pressure resistant gasket goop on the shelf so I figured I would use that. I cleaned both the pump housing and the Pump plate of any grease, etc.
I placed the plate on the motor and replaced the pin, the eccentric and the impeller. I then put a thin bead of the gasket material on all of the pump housing edges, with the exception of the water intake areas. I also put a bit of the gasket material around the water tube seal as this showed a bit of deterioration. I carefully placed the housing back over the impeller and screwed the 3 screws back in tightly. I let it dry overnight and today I started the motor. The motor started and low and behold I saw some water start to pee out of the return elbow.
Attachment 116136
I ran the motor for a while in a tank and adjusted the mixture. It is running just fine. Perhaps better than it has in decades. It has a rebuilt Carburetor with new modified Mercury float and a new impeller.
Thanks for all the help I got from you guys in getting an understanding on how this water pumping mechanism was supposed to run, it allowed me to come up with a solution.

[iggyw1]

I once had a 25 h.p motor that I had the same problem with after I replaced the impeller. No water pumped. Turned out that I had the water tubes in the housing grommets, but the water tubes were in backwards. The tubes on that motor were cut at the ends at about a 45 degree angle. These angles had to point towards the inside of the impeller housing, and I had them pointing to the outside, so the back side of the water tubes were blocking the holes into the pump, and no water could be sucked into the tubes.. Check your water tubes and see that they are in correctly. Just a thought to help you out. ALSO, check to make sure your wear plate is not upside down. Some of them can be put in both ways, some will only go in one way for the screw holes to line up. If its upside down, the "tang" in the wear plate is on the wrong side.