Mercury 25hp 0C196683 water flow frustrations

[wolfee]

I started the motor up in the driveway with waterhose muffs on and after a few minutes I saw smoke coming out of the "tell-tale" hose. I shut the motor off and sure enough the hose was blocked up. After clearing the hose, I still can't get any water coming out of the tell-tale hose. I've read a number of posts on the internet about this issue and ended up replacing the entire water pump, which made no difference. Here are my frustrations:

I bought the manual for this motor from Mercury Marine and it shows a groove near the top of the drive shaft for an O-ring (just below the splines). When I replaced the water pump, I saw the groove in the drive shaft but no O-ring. When I ordered the water pump and went to pick it up, I asked the salesman about the O-ring and his blow-up of the lower unit/drive shaft doesn't show the O-ring. If I go to Mercury's part Catalog for 0C196683, there is no O-ring on the driveshaft. The manual I bought DOES have a picture of the O-ring and actually suggests replacing the O-ring if you pull the lower unit. Like I said, there is a groove for the O-ring but no O-ring. This has nothing to do with water flow, but it's frustrating as heck.

The same blow-up of "Cylinder Block and Covers" shows a thermostat, but my motor doesn't have a thermostat and there doesn't appear to be enough room for one either. I pulled the cover off where the thermostat would be and there's nothing there, no room either.

So I pulled the "Screen Water Inlets" off and made sure that was clear. Seemed fine but I noticed there is only a small rectangular opening at the top of the opening where the Screen Water Inlets are and frankly I'm not sure a hose with muffs would even force enough water into the lower unit for the impeller to move water. So now I'm back to square one and I think I just need to take the boat to the lake, start the motor and see if I have any water flow. Since there isn't a thermostat (that I can see anyway), there should be steady waterflow.

The only other thing I could have checked would be the water tube itself right?? I don't feel like pulling the lower unit again, so I think I'm going to try the "put it in the lake" plan first. If it still doesn't move water, then I'll troll around a fish for a bit then head home. Am I missing anything?? Very frustrating.

 

[flyingscott]

DO NOT run the motor with no water flowing you have something wrong. That motor will pump just fine on muffs!! You need to pull the lower unit off and double check your work. Was the old impeller in one piece when it was removed or in pieces? Is the key in the impeller? Are the washers on the impeller? Did you line up the water tube correctly? Is the seal on top of the pump housing? Is the impeller oriented correctly? Look on the block for the silver disc and see if there is a serial # there. Or put up a pic of the back of the block that should have a thermostat or you could have an older block on there. If you run that motor with no water you will wreck something. The o-ring needs to be on the driveshaft it protects the drive shaft splines from water so it won't rust into the crankshaft.

 

[Jkcckc2002]

If it was a new pump it should be inspected and replaced if needed. I would remove the tell tale hose at the block and while the lower unit was off try to pressure water through the engine with out the hose. If it does then the hose is plugged. Dirt dobbers do some serious pluggjng sometimes.

 

[wolfee]

DO NOT run the motor with no water flowing you have something wrong. That motor will pump just fine on muffs!! You need to pull the lower unit off and double check your work. Was the old impeller in one piece when it was removed or in pieces? Is the key in the impeller? Are the washers on the impeller? Did you line up the water tube correctly? Is the seal on top of the pump housing? Is the impeller oriented correctly? Look on the block for the silver disc and see if there is a serial # there. Or put up a pic of the back of the block that should have a thermostat or you could have an older block on there. If you run that motor with no water you will wreck something. The o-ring needs to be on the driveshaft it protects the drive shaft splines from water so it won't rust into the crankshaft.

1. Was the old impeller in one piece when it was removed or in pieces? One piece.
2. Is the key in the impeller? Yes
3. Are the washers on the impeller? Yes
4. Did you line up the water tube correctly? The water tube fit inside the rubber boot/fitting, which is also new.
5. Is the seal on top of the pump housing? Yes
6. Is the impeller oriented correctly? Pretty sure, a new impeller is too big to fit inside the pump casing, the manual states to rotate the drive shaft clockwise to get it to bend enough to fit inside the case. That's what I did.
7. I'll check the block itself and see if there is a serial number but I haven't seen one. I'll also get a pick of the back of the block.

The tell tale hose was actually blocked by mud dobbers, that has since been cleared, I can blow air through easily.

 

[wolfee]

No Title

The only numbers I could find on the block were:
A XK 1 3 <the 3 is inside a square>
14406-C

"14406" is listed as "COVER" in Mercury EzPartsWeb catalog for my motor.

"99762" is also on the "COVER IGNITION COIL" which matches the number in the Mercury EzPartsWeb catalog.

Should I be able to see a thermostat after I take off the "COVER" and "GASKET" holding the tell-tale hose and "ELBOW"? I see nothing. Do I need to remove the "COVER ASSEMBLY" in order to see a thermostat?

Thing is, the same catalog blow-up doesn't show an O-ring on the drive shaft, which I have. This motor has been in the family for at least 20 years and has always run great.

Here are pics of back of block where the tell-tale hose attaches to the elbow. I couldn't get a good pic of the numbers on the block, they were upside down and in a tight spot.

 

[flyingscott]

When I looked up your serial # it shows an o-ring on the shaft it should have come with the waterpump kit. I can't tell if you have a thermostat or not the pic is small. Where the elbow screws in for the pee-hole is there a small cover with 2 bolts holding it on. If you have the cover you need to take it off and look under there. Once the cover is off start the motor and see if water comes shooting out.

 

[wolfee]

The "O-ring" in the water pump kit is the one that slides all the way down the drive shaft and sits on top of the water pump. The groove in the drive shaft is clearly for a circular o-ring, where as the one that slides down the shaft is not. It's more of a sleeve, if you know what I mean. I'll pull the elbow off again, and yes it has two bolts holding it on. 25, 25 Sea Pro, Super 15 (2 Cyl) is the motor category in the Mercury parts EzPartsWeb blow-up and it doesn't show the O-ring at the top of the drive shaft, just the one at the bottom. Adding photo of drive shaft.

 

[flyingscott]

http://www.ebay.com/itm/Water-Pump-K...xXhk8v&vxp=mtr this is the kit for your motor and it comes with the o-rings. Take the thermostat housing off and look underneath it be careful to not break the bolts. You don't have to put the oring on if you don't want to I am not going to argue the point with you.

 

[wolfee]

Here's the pic from the link you gave me:

It's exactly the same water pump kit I installed. The black o-ring in the top right slides all the way down the drive shaft and sits on top of the water pump. The two fiber washers are for each side of the impeller, the 3 smaller washers/o-rings are not used, I guess for another model. (they're much too small for the drive shaft) There is no O-ring for the top of the drive shaft in this kit either. It's dark here now, so I'll get a look at the thermostat housing in the morning. Please don't think I'm arguing with you, I really appreciate the help. Hopefully I'll pull the thermostat housing off and the thermostat will be inside the housing and water flows out of the port when the motor starts. Then it's just a thermostat, otherwise I'm guessing the only thing left is the water tube from the pump up into the block. That or maybe the fins on the impeller got stuck when I tightened the pump case down? It seemed flush/tight to me. Anyway, thanks and I'll be back in the morning EST.

 

[wolfee]

Well I took the water pump apart again and the fiber washer that sits above the impeller was torn to shreds, there was only one piece of it left about 1/4 inch long. The Impeller looks worse than the one I replaced. So now I'm confused. Everything seemed to sit correctly but maybe having to spin the drive shaft clockwise to get the impeller in place moved the washer??

Note: there's another thread here that I started about a week ago, ignore that one.

 

[flyingscott]

There is no way that washer could have moved unless maybe it was broke. Did you put the impeller in the housing first then put it on? Or the key slipped out and jammed on the impeller and tore the washer up. Try installing it this way: put the first washer on then the impeller and key then the second washer. Then lube up the housing with dish soap. Now make a fist around the drive shaft with you right hand and turn it the way your thumb is pointing. Push down on the housing while you are turning the shaft. It will drop right on and the vanes will be pointing the right way. Make sure the oring is on the pump housing.

 

[wolfee]

Thanks! I had to order another pump kit, due in 2 days. I was wondering if there was a safe way to lube up the housing to make it easier to get the top plate on, great idea. Should the drive shaft be greased? I'm guessing yes for the splines, just wondering about the shaft. I'll let you know how things go once I get the second kit, ordered from iboats

 

[flyingscott]

Just grease the splines.

 

[wolfee]

Well...lessons learned.

While waiting for my second water pump kit to arrive, I decided to put the old impeller back on (it looks better than the new one), use the dish soap trick to get the cover plate on easier, and grease the splines on the drive shaft. I put the lower unit back on and STILL didn't get any water flow. I also shot compressed air up through the copper water tube and air came out where the tell-tale hose connects. (the mount plate was off)

So I went back to my original thought that maybe the muffs weren't giving enough water pressure to reach the impeller. I went to the shed and found a bucket big enough to submerge the prop and deep enough to reach the water pump level. I started the motor and the tell-tale hose was peeing like a race horse! So to anyone out there trying to test water flow with muffs, before you go through two water pump kits and possibly even a new thermostat, just get a barrel and fill it up with water, or do what I wanted to do in the first place and take the boat to the lake.

Thanks to everyone for all your help and advice, I actually learned a lot about troubleshooting water flow