Impeller problems

I own a 1981 9.9hp that isn't pumping water. I noticed a while ago it was pumping water inconsistently so I decided to check the impeller. I found some corrosion and made the below repair:


Now that I put it all back together it doesn't pump at all. I did a whole bunch of tests and came up with two problems I'm going to need some help diagnosing.

First-I took the lower unit off and noticed it had to be submerged up to the bottom of the impeller before it started to actually pump water. I tried using regular 'ears' but they didn't work. There is no clog. Could there be a seal problem where the impeller housing mounts (are you supposed to use any gasket material for that seal?) Or does the engine (sail model with the extended drive) need to be submerged that deep before it starts pumping? I thought all you needed submerged are the bottom holes (screened suction holes)..am I wrong?

Second-I found that when I blow some air or water up the copper pipe (the pipe the impeller normally feeds) the air/water does not come out the hole on the outside of the engine (where the exhaust and water spray out of, normally). Can that pipe be broken or corroded? I can hear the air coming out before the pipe reaches the bottom of the engine. How do you changed/test/inspect that pipe?



Thanks so much!
This is a link to a old thread.I own a 1981 9.9hp

Just made this picture:

-The engine has to be submerged up to that red arrow (just below that second fin) for the impeller to pump. Is that normal or is there a problem? (I found this out with the lower unit off - spinning the shaft with a drill). I put a set of ears on the lower unit and it didn't work at all (maybe the ears weren't making a good enough seal?? Square old ears that didn't fit the curve of the engine?)

-It seemed when I blew air in the pee hole (blue arrow) or in the water tube the air wasn't making it all the way through. I think the water tube isn't connected to the bottom of the engine (or broken) how do I get to it/inspect it?

Maybe I have two problems...hmmm HELP!!

Thanks.

Re: Impeller problems

When you submerged it to the proper depth, did it pump water? You've written a lot, but it's unclear whether it has ever pumped water during your tests.

If you ran even a new impeller dry, then it's probably destroyed. You may have to put a new one on. Also, if you tried running water up the water pipe into the engine and none emerged, then there may be chunks of an old impeller in there. Those will have to be removed. Sometimes, you can reverse flush and get rid of them.

Tell us more of exactly what you have tried, and at what stage in your repair attempts. Your post is a little confusing.

Re: Impeller problems

The water pump plate has to be an air tight seal to the gearcase (where your patch is). Also, the pump should be submerged before starting the motor. It is a good water pump but a lousy air pump (has to be full of water).

The powerhead has to be removed if you plan to replace the water tube. You can see an exploded view and parts list at http://shop.evinrude.com/

Re: Impeller problems

Sorry for the confusing post.

After installing the new impeller because I noticed intermittent pumping I put the ears on the engine and ran it. It did not pump water from the pee hole.
I submerged the engine (to what I thought was proper depth) and ran it. It did not pump water from the pee hole.

I took the lower unit off and spun just the lower unit (with a drill on the shaft). With the ears, it did not pump. When submerged up to the bottom of the pump, it started to pump strong...with good pressure.

While the lower unit was still off...
I tried forcing water up the water tube. None came out the pee hole. it came out of the exhaust housing (like it wasn't making into the engine. I tried forcing air both through the pee hole and the water tube. It sounds to be coming out where the water tube connects to the engine (I can't see).

I have yet to put the lower unit back on.

This is my new theory...The pump is working fine. The ears were not seeling good enough to work and when I had it submerged, it might not have been deep enough.

Unfortunately, I think its a problem with the water tube.

Correct me if I'm wrong....
1-I should be able to force water up the water tube and have it come out the pee hole????????????
2-I should be able to use the ears (if everything was working correctly)????
3-The engine has to be submerged up to or over the impeller to pump correctly (assuming the water tube is ok)????

No, the engine has not pumped water after the new instalation but once I submerged the lower unit, while it was off the engine, I did get the pump to work...just not while connected to the engine. like I said, I have a feeling the pump is working but the water tube is busted. I guess maybe I should connect the lower unit again and submerege it to the correct depth now knowing that the pump does pump. If nothing comes out the pee hole...knowing what I know now, its probably the water tube...right? I think the ears not working was a fluke because of the weird seel they made. What do you guys think????
Thanks so much!!!!!!!!

Re: Impeller problems

You have to consider some facts of life here when diagnosing your problem.

1. Yes, if you run some water up through the tube there should be some come out the tell-tale and most of it should go through the cooling system and come spilling back out the housing.

2. The water pump needs to be submerged before starting the motor.

3. But once the motor is running, the exhaust blows the water out of that area around the water pump. That is why the pump must be sealed to the gearcase (where your patch is). If it leaks there, the exhaust in the area goes in through the leak, into the pump, and kills the pumping action. For that reason, it may pump fine when submerged and off the engine, but not when installed on a running engine. When off the engine, it is water that is going in through the leak and that doesn't stop it from working. Exhaust/air is the culprit.

Re: Impeller problems

Thanks so much FR! From what you said it sounds like everything is working just fine. I think my old school ears were not making a good enough seal to work and when I submerged the engine I didn't submerge it far enough. I'm going to seal the plate to the lower gear case and bolt everthing back up. My hopes are high. Thanks again!

Re: Impeller problems (UPDATE QUESTION)

Re: Impeller problems (UPDATE QUESTION)

Ok, I bolted everything back up and ran the engine in plenty of water. There is a VERY light spray of water coming out the tell tale. A very little bit drips out but at times its barley noticeable (if its coming out at all). This is all at idle in the bucket. Is this cofrrect? How much water normaly comes out?

I also noticed A bit of water dripping out of this: (its a small rubber gromet/hole attached to a hose running to the block. What is this??? The first picture is the rubber hole...the second picture is of the tube[/IMG] it conects to (the bottom most tube in the picture).







THANKS!

Re: Impeller problems

Your last set of pictures and the description thereof is the tell-tale. What you've mistaken as the tell-tale sounds like the exhaust-relief port (confirmed by the picture with the blue arrow).

The tell-tale bulkhead fitting for the lower cowl has a tendency to get clogged. Try running some weed-whacker line up it and I'll bet you see a nice steady stream.

Re: Impeller problems

Yes, there should be a strong squirt out the tell-tale fitting in the pan. And yes, the big holes on the back are exhaust relief holes. It should have a healthy spray of water drops out there too.

Re: Impeller problems

What is wrong is likely the grommet on top of the water tube has collapsed.This is a common problem on 9.9 and 15 hp especially ones that werent flushed or ran in salt water.The fact you cant get air through is classic.A trick I have used with some sucess ,take a wire coat hanger,straiten out long enough to go up to the grommet point(stops)take a hammed and beat a cutting edge on the tip of one end of the wire,Using a battery powerd drill,chuck the wire end and slowly try and bore through the blocked end.The tube is copper the engine is alum.that creates a corrosive element,after time the grommet is forced closed.The real fix means taking the powerhead off and locating the problem,the fix becomes evident,tube will be removed through top,clean up throughly ,new grommet,powerhead gasket,reinstall powerhead,that IS the problem

Re: Impeller problems

iwombat said:

Your last set of pictures and the description thereof is the tell-tale. What you've mistaken as the tell-tale sounds like the exhaust-relief port (confirmed by the picture with the blue arrow).

The tell-tale bulkhead fitting for the lower cowl has a tendency to get clogged. Try running some weed-whacker line up it and I'll bet you see a nice steady stream.

Click to expand...

Wow...I'm suprised!! From my understanding...the big hole on the back of the engine (the one with the blue arrow) is the exhaust relief port. Which should have a healthy spary of water coming out.

The rubber grommet on the bottom of the engine case (pan) in the last picture (upper right hand corner) is the tell tale??????????? I never new...I thought the big hole with the blue arrow was the tell tale.

The engine didn't run for YEARS...the more I run it, the better the spary out of where the blue arrow is. Its now a very healthy spray and the engine runs very cool. But the rubber grommet still has a slow drip. I'll try cleaning it out! Thanks so much.

Just to confirm...the rubber grommet is the tell tale.?
THANKS AGAIN!

Re: Impeller problems

Yep, that little plastic fitting is the tell-tale. It's a small siphon off the cooling jackets as it comes into the motor (tapped in off the exhaust cover). It just lets you know the water pump is working. It should ALWAYS be squirting water. Its also a great place for insects to build nests, so they do need chasing out once in awhile.

Water will only come out the exhaust when the t-stats have opened up.

Re: Impeller problems

Just wanted to say thanks very much! I had to pull off the tell-tale hose and replace it. I also had to clean the 90degree fitting to the jacket. Both were clogged like I've never seen. I had to use penetraing oil and a drill bit (turn lightly by hand) to get the sand out of the 90degree fitting. I now I have a nice strong steady stream coming out.
Thanks so much all!