SOLVED: !963 Evinrude Lark V repaired water pump not working

[SteveVT]

After repairing the water pump I am getting almost no water to the engine head after starting the motor. I shut down immediately. I let the engine cool removed the thermostat and left the thermostat cover off, to eliminate the thermostat as the problem. I started the engine, and got almost no water coming out of the thermostat inlet (the smaller port side vertical pipe, I assume). Just a few drops. I shut it back down

I imagine water should always flow out of there if the engine is running. I put a garden hose nozzle on that pipe and back flushed it, but there didn't seem to be any obstruction. Trying the motor again yielded the same result.


Here's the repair procedure I used. Please let me know if I did anything wrong or skipped something necessary:

1.) I pulled the lower unit off removed the pump housing and pump plate.
2.) I replaced the upper gear case drive shaft seal under the plate with a new one..
3.) I cleaned the lower water pump plate and pump housing with Xylol
4,) I carefully put 3M 847 only on the contact edges of the gear case casting ridges under the plate
5.) I replaced the plate
6.) I replaced the drive shaft
7.)I put a new woodruff key in the shaft (all new pump parts below, including this one were from a genuine OMC/BRP waterpump kit)
8.)I placed a new impeller on the shaft and aligned with the key
9.)I prepared the pump housing by replacing the shaft seal, and the 2 water tube grommets with new parts
10. I greased the impeller vanes and grommets w/white lithium grease
11.) I put 3m 847 on the contact ridges of the water pump housing, and greased the shaft seal
12.) I slid the housing down the shaft and carefully rotated the drive shaft in a clockwise direction, only, to set the vanes. It rotated without binding.
13. I used new kit screws to fasten the housing.
14.) I added a new rubber O-ring on top of the housing to mate with the lower exhaust housing.
15.) I reassembled the lower unit to the outboard following the manual procedure. The flywheel was ONLY ever turned in a clockwise direction by hand to mate the splines.

Any suggestions why the pump might not be working? Or something I did wrong?

Thanks!

 

[oldboat1]

good candidate to test manually deep in a tub of water -- carefully use a half inch drill, turning clockwise. Don't remember how the dual tubes work, one recirc. as I recall, but should see a flow of water from the pump at one of the grommets. (also not sure, btw, what reversal of the tubes at the pump would mean for operation -- might be the issue).

 

[Joe Reeves]

The pump is NOT self priming... it must be submerged, having the water approximately 4 or 5 inches over the joint where the lower unit bolts up to the long exhaust housing.

It does not matter which way the driveshaft rotates when your installing the impeller. It aligns perfectly to the flex condition as needed as soon as the engine cranks over.

If the water level is as I describe, and the unit does not pump water, remove the lower unit and inspect your work.

 

[SteveVT]

Thanks oldboat and joe reeves.

When tested, the motor was in a 55 gallon drum filled up higher than the water pump (to slightly above the horizontal plate above the anti-cavitation plate).

The water tubes are parallel, so reversal isn't possible. But maybe the tubes cut or deformed the grommet (since the copper tubes are cut at an angle, and so are pointed.) impossible to see what's happening there while trying to maneuver the lower unit up into place and also engage the shaft splines AND fish the shift wiring through the side exhaust cover plate. I was definitely cursing this job, and not looking forward to doing it again, especially if something else unrelated is wrong.

One water tube is supply, and the other is a return from the thermostat housing, I believe.

This engine is a long shaft (w/extension). So the water has to pump a higher distance vertically than a standard Lark V.

The metal water pump housing is original, as a guess. This isn't the type with the replaceable inner rim, like the modern plastic ones are.

I'd replace the housing but I think finding a new one would be next to impossible. (If someone knows of a source, please let me know.)

I do like the drill test idea, oldboat, to discover if it is the pump, or something else.

 

[SteveVT]

Today I pulled the lower unit off again, and tested the pump by submerging it up to just under the water tube grommets. I was going to use an electric drill to turn the driveshaft to test it but I gave it a few turns by hand and water gushed out of the outlet, so it was obvious 750 to 4000 rpm in the engine was going to do the job.

Next I checked the water tubes up into the powerhead by putting a garden hose nozzle against the inlet tube. I could hear the head filling and then water shot back down the other tube, the outlet to the pump. This motor has a two water tube system and recirculates a lot of the engine water when the thermostat is closed, which warms it up. This proved that there was no obstruction in the tubes.

Finally, examining the ends of the copper water tubes, I could see a small shiny rough burr on the end of the pump outlet tube. I know that wasn't there when I reattached the lower unit -- I had checked and greased the tube ends to fit more easily in the new rubber grommets. I filed the tube smooth again and re-greased it.

Checking the grommets themselves, I could see that the pump inlet grommet had been stretched and seated better than the outlet grommet which looked as it did new.

I'm pretty sure therefore that I must have missed getting the outlet pipe into the waterpump grommet, and the pipe probably got the burr from tightening down against the outside of the metal water pump housing.

Yesterday it was hard to get the unit back in place with everything lined up (working alone), but I've since found a video where a ratchet tie down strap is used to assist raising the lower unit in place. Instead of struggling to lift it by hand, it can hold the unit maybe a half inch from fully mated and you can check inside with a flashlight to make sure every pipe and wire connection is where it should be:

Raining tonight and tomorrow, but I think ensuring that the tubes are mated just before bolting up will probably be the solution to my water pump problem when I get a chance to reassemble the leg.

I'll post the results when I can do it.

 

[oldboat1]

It is sometimes easier to reattach the l.u. with the motor tilted -- gear case supported on a ShopMate or something similar. It seems to me I used to fish the shift wires up from the top somethng like an electrician fishing wires through a wall. Concentrate on fitting the water tubes and the driveshaft, and hand screw in two or three bolts a couple of turns for support and alignment as soon as the l.u. is up within reach.

 

[jimmbo]

A bit of soapy water makes it easier for the pipes to slip into the grommets

 

[SteveVT]

Thanks oldboat and jimmbo. I bought a ratchet strap this morning for $12 at the hardware store, and also raised the motor as suggested oldboat instead of trying to do it vertically. Reinstalling was a piece of cake compared to the first time -- the ratchet strap made it simple, and I could look inside to see the pipes entering the grommets properly. It was easy to fish the wire and engage the powerhead splines, too. It just all went together like it was meant to.

And the pump and thermostat all worked as expected, so no problems there any more. I'm sure the outlet pipe must have missed the grommet last time around.

I thought I was home free, but a new problem became apparent. I'm only running in the tank on one cylinder (most of the time -- I can hear the second one kick in occasionally). I'm opening a new thread for this, and will add more details there. This one on the water pump is solved. Thanks for your help!