Mercury 9.8 with no water

My Mercury 110 quit spraying water awhile ago, recently i removed the lower unit and found my impeller destroyed. I put a new impeller in and it will still not spray water. I ran water through the exit hose and it came out of the bottom of the engine so i know there is no obstruction in any of the hoses, I also notice when i run my engine for the few seconds to try to get it to ciculate water that exhuast smoke comes out of the little hose along with some air pressure. I don't know why air would be coming out of that water hose, i know my merc 850 doesn't do it. Is something seriosly wrong or could there be a crack in the copper tube that runs up through the lower or something?

Re: Mercury 9.8 with no water

Your Exhaust cover gaskets are probably shot. Its a common problem and a cheap fix. The gaskets fail and as the exhaust pressure builds exhaust seeps into the cooling system, which stops the flowa of water to the pisser because the pisser takes from the top of the water jacket. There are two gaskets and they're about $5 canadian each. The most annoying part is getting the exhaust cover bolts off without breaking them. Don't put much force on them and use lots of heat/penetrating oil.<br />Good luck,<br />Eric

Re: Mercury 9.8 with no water

these motors have a seal at the top of the water tube that swells shut from age..overheating..etc..the power head needs to be removed and check/replace this seal..Its probably time to replace the exhaust plate and clean out the block anyway..make sure you replace all the water pump housing tube seals too...Al..

Re: Mercury 9.8 with no water

He said water will run thru it backwards from the pisser, so it's probably not a swollen seal.<br />Eric

Re: Mercury 9.8 with no water

Well i tried removing the large flat plate on teh porst side as seen from the back, it had about 8 bolts on it. I removed two succesfully and snapped one even being ginger on it. There is a lot of white corrosion around teh gasket on this thing, i think maybe if I will have to use a benzomatic torch to heat up the remaining bolts, it swells them up a bit then shrinks them, kinda worked on my 850. So is the one with all the bolts that is flat the one i need remove? I really don't want to take any more apart than i need, i'm afraid the metal will break, i broke my water jacket cover on my 71' merc 850 just by handling it, i think the salt at away at the pot metal they used

Re: Mercury 9.8 with no water

Ya, that's the right one. A torch is pretty much a must for getting those bolts out, as I said "Don't put much force on them and use lots of heat/penetrating oil." I'm always amazed when I watch my friend who's been working on these engines for years get each bolt withing a couple degrees of meting and working them out. It can usually be done with much less heat than that though, I usually use the coolest tip on my oxy/acetylene, but a bernzomatic torch would definately do the trick. If there's enough of a stud left you can usually get a broken bolt out with vice-grips and a heat, if not you'll probably have to helicoil it. Behind that plate there are two gaskets separated by a thin stainless plate.<br />Eric

Re: Mercury 9.8 with no water

Well i been waiting awhile for the baffle plate and 2 gaskets, plust the main water jacket cover gasket, but i finally got them. I got teh whole motor back together now and i'm waiting now for the silicone i used to cure, can't wait to fire the motor up and see if it pisses water now. I got some hightemp silicone, but something tells me i shouldn't have used silicone at all with these gaskets

Re: Mercury 9.8 with no water

Ok ran and no water came out, checked all the channles in the baffle plate cover they are clear, i decided to use water pressure to try to spray up the copper tube that puts water up into the power head, water doesn't seem to go up it, the copper tube seems to be obstructed, i've tried to work clothes hangars from both sides, and i've put lime away down from the top, think the salt water corroded the copper pipes, i'm going to use an air compressor tomorrow to try to blast the obstruction out

Re: Mercury 9.8 with no water

if blades were missing off the old impeller their may have gone up in the tube also when you change the base plate on the impeller did you look down in the cavity where the water comes up to the impeller when the impeller comes apart I find they go down in the cavity and wont let the water come up,take a coat hanger and push it up thru the water tube gently as you are blowing air it may help to get the pieces stuck in the tube if their is any in their

Re: Mercury 9.8 with no water

You said you ran water back through - where did it come out? The pisser is not the only outlet for water, and if water was just dribbling down the inside of the mid-section, then you've got a blockage somwhere else.<br /><br />As was mentioned previously, check for bits of rubber lodged at the top of the water tube at the nylon bushing. You'll have to pull the powerhead off the motor to do this. Make sure everything is cleared up. Compressed air can tell you if things are clear or not. You can also run the lower unit with a drill to see if you're getting water as far as the top of the water tube (with powerhead removed). Use a cordless, as corded tools and water don't mix.<br /><br />- Scott

Re: Mercury 9.8 with no water

InlineAl is right, the grommet in powerhead is blocking waterflow from coming in. Just finished a 7.5 with same symptoms.

Re: Mercury 9.8 with no water

Is the key in the impeller? that happened to me.

Re: Mercury 9.8 with no water

YAY! I'm happy to say that after inspecting the lower unit and hooking it too a drill i found that the impeller was not spinning. I opend up the pump housing and took a look and the key was still in place. What had happend is corrosion over the years wore the shaft down enough that the key doesn't stick out far enough to spin the impeller. I took the lower unit and impeller to Clear water marine and let **** Clark have a look, he was able to cut some steel sheet and put it behind the key to help it stick out, put the whole thing back together today and ran it, runs sweet water sprays like its cool, only problem i have now is a milky exhuast water because exhaust is still barley leaking into the water, this is because the top left bolt on teh exhaust cover is stripped, one or two drops of water come out of the cover every nwo and then and the water is very very warm that comes out but it is pissing water and it doesn't over heat, my motor is back in buisness, thanks chinese walker for the drill idea, thanks murray for suggesting the impeller key which was actually the problem, and thanks Eric B my exhaust cover gaskets were shot but are good now