# Help! No water jetting from my Mercury



## Tin Yachtsman (Oct 1, 2010)

I need a bit of help from the forum, please. I put my tin in the water today after having it sit up for a couple months. Fresh gas and oil were used. It started up fine, idled well, took off like a champ, but only made it about 200 yards before stalling and smoking very bad. I didn't really pay attention to whether or not it was pumping water (my mistake, I know) but the water pump was extremely hot when I took off the cover. I let it cool down for about an hour but it wouldnt start. At home tonight I was able, thankfully, to get it running again. I had the flush attachment on and there was no water coming out. Before I take it in for service, how can I check for clogs in the cooling system? Any suggestions at all on what to do are appreciated.


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## Captain Ahab (Oct 1, 2010)

Replace your impeller!

What do you mean teh water pump was hot? How did you feel that - it is located in the lower unit


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## Quackrstackr (Oct 1, 2010)

The flush attachment is meant for flushing... not running the motor.

I don't know if water even gets to the impeller via the flush attachment.


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## Tin Yachtsman (Oct 1, 2010)

Okay, try to ignore the fact that I have no idea what I'm doing. My two-stroke, 15 HP, 1991 Mercury outboard isn't jetting water out of the outlet under the top cowl. It ran for about 90 seconds this afternoon, then stalled, smoked, and smelled burnt. An old-timer at the dock suggested the problem is a water pump issue causing overheating. When I got home, I removed the prop, hooked up the flush attachment because I thought that would put water in the system, and tried to start the motor. After several pulls, it did run, but I turned it back off when I didn't see any water coming out of the outlet under the cowl. I'm looking for suggestions on what could have caused the stall/smoke and how to troubleshoot it without launching it again. I hope that clears things up a little. Thank you.


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## Jim (Oct 1, 2010)

Captain Ahab said:


> Replace your impeller!
> 
> What do you mean teh water pump was hot? How did you feel that - it is located in the lower unit




X2


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## Quackrstackr (Oct 1, 2010)

Running for 90 seconds didn't get your motor hot enough to shut down from overheating because of a failed water pump, most likely.

Overheating will make steam come out your exhaust, not smoke.

You may have a head gasket issue or you may have just had some gunk in your carb that gummed up the system for a bit.

Get a set of muffs that hook to your water hose and go over the water intakes on the lower unit and see if it pumps water. They sell them at Wal Mart here.


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## Tin Yachtsman (Oct 2, 2010)

Get a set of muffs that hook to your water hose and go over the water intakes on the lower unit and see if it pumps water. They sell them at Wal Mart here.

Okay, that's what I thought I was doing. I followed the instructions in my owners manual. No water pumped out.

Here's what I did:


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## Quackrstackr (Oct 2, 2010)

That should have done it, then.

That isn't the same kind of flush system that they have on the newer motors. Mine has a hose connection for flush that goes right into the block.


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## crazymanme2 (Oct 2, 2010)

I'm very familiar with Mercs.What year is your motor?


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## Tin Yachtsman (Oct 2, 2010)

crazymanme2 said:


> I'm very familiar with Mercs.What year is your motor?


When I bought the boat, I remember looking up the year from the serial number. I want to say it was a 1991, but I may be off a year one way or the other.


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## crazymanme2 (Oct 3, 2010)

In the 2 pics that are shown one is where you put your flushing attachment over & the other pic is where your water should be coming out.Pull your cowl off & see where your tell-tale hose connects to motor to make sure it isn't plugged.I don't shoot air in hose because all your doing is pushing junk into your motor.


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## Ranchero50 (Oct 3, 2010)

Do you have the manual, if not I would suggest getting one. OEM are on eBay, usually for under $40.

On my former 90's Merc 9.9 there was a thermostat that would stick shut on occasion. It's on the back of the head by the telltale hose. If memory serves there were just three little bolts that held it on. I would suggest removing the thermostat, then blowing air through the passages or water from the lower unit up to make sure you didn't suck up some weed or other crap causing a blockage. Heck, you may even be suffering from mud-dobbers if it sat through the summer. 

If run in weedy water a foot of weed eater string works great for clearing the telltale line. Outboard jet boaters usually keep it dressed in the control zip ties. 

If the engine was oil smoking I'd suspect the fuel mixture was too rich or the choke or float was sticking, something along that route. 

When it shut off, did it still turn over? If so then I'd chase the fuel ckt after cleaning out the coolant passages. If not it may have overheated. With the oil smoke I doubt it lean seized.

Jamie


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## Captain Ahab (Oct 3, 2010)

Al that stuff is great - but I STILL CHANGE THE IMPELLER - that is your water pump and if it is not pumping, then change it. Not expensive and it is the most important part on your engine


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## Tin Yachtsman (Oct 5, 2010)

Thank you all for the suggestions. I will definitely go through them all to try and get to the bottom of the problem. I won't really be able to spend any time with it until Friday. I have an owner's manual, but not a service manual. I will look into getting one off Ebay. I will let you know how it goes. Thanks again.


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## RBuffordTJ (Oct 6, 2010)

Man you got some good suggestions so far. If it were me, first check the 'pee' tube to make sure it is not blocked, pull it off the block and blow air through it, DON'T blow back towards the block.

No blockage? Drop the lower unit and replace the impeller (water pump) and housing. Kits should be under $100 for the whole package. If your impeller is broken up and in pieces then put it on a bench and reassemble it best you can. If pieces are missing you will want to back flush the engine to try and push them back out or they will stay in the powerhead and randomly block passages causing overheating from time to time. That will drive you crazy. Bottom line, get all the pieces out.

While you are at it replace the thermostat, they are cheap, and once damaged they may never work properly again so don't take the chance, replace it. While it is out is a good time to backflush, put the hose in there and push the water out the water tube while the lower unit is off and see what comes out.

Hope that helps some.
Bufford in Orlando


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## Tin Yachtsman (Oct 9, 2010)

I made a little progress with the motor yesterday. I got the tell-tale hose off and cleared it out. It was a little gunked up, but not totally blocked. Took the water intake plate off and checked for blockage there, but didn't find any. I didn't feel confident about dropping the lower unit without a service manual, and I didn't have a gasket for the thermostat, so I didn't try those steps. I got a service manual off eBay and just ordered a new impeller, housing, and gaskets to replace the impeller. So I am going to be digging deeper into the motor soon. 

Question: How good is RTV Silicone at replacing gaskets? It looks like there are some gaskets in the water pump that are no longer available. 

Thanks for the continued help.


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## Tin Yachtsman (Oct 12, 2010)

I "think" I found the problem. Check out the pics below. 








Now to wait for the parts to come in, and then see if I can put it back together properly.


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## RiverRunner (Oct 12, 2010)

Yeah, that was definately your problem! Dry rotted impeller. Hopefully you can still see which way the ears on the old impeller folded in, because that's the way the new one needs to go.


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## crazymanme2 (Oct 17, 2010)

The new impeller can go in either way.Just make sure you turn the driveshaft clockwise when installing the water pump cover,& make sure the key for the impeller doesn't slip out.


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## Tin Yachtsman (Nov 5, 2010)

Success! I got the whole thing back together and took it out today. It ran great! There was a nice, healthy stream of water coming out, and no problems to report. I even got about 45 minutes of fishing in and caught a couple small bass. I owe everyone who helped a huge "Thank You" because I doubt I would have tried this repair if I didn't have this forum to fall back on. You guys are great. =D>


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## RBuffordTJ (Nov 15, 2010)

=D> 
Way to go!


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## Outlawtoon (Nov 29, 2010)

Flush attachment is only meant for flushing out salt was or if you where running in muddy or real dirty water. The flush attachment will not cool the engine. You still need to either add muffs / garden hose set up. or stuff it in a barrel.


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## DuraCraft (Nov 30, 2010)

I love this post! That was a good ending story; good for future reference, but I hope I don't need it!


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