Water Pump Woes

[Fishallot]

1993 115hp 4cyl<br />I replaced my water pump yesterday, my first time on an outboard, and think I may have screwed it up. When I fired the motor up today at the ramp water was leaking out where the shift shaft goes into the lower unit. Here's a pic that shows this.<br /><br />

<br /><br />I also noticed that my water pressure gauge is reading very low, 1 psi at idle and about 4 psi at WOT. I'm not sure what it should be reading as the water pump that was in the motor was old and worn when I bought the boat. The reading I'm getting now is actually a hair better then with the old pump.<br /><br />I think the problem may be that when reinstalling my lower unit I didn't seal off the exhaust chamber properly. I put a bead of silicone on the back of the pump housing but neglected to put a bead on the edge of the chamber like there was before. Here's another pic that shows what I had when I first pulled off my lower unit.<br /><br />

<br /><br />I'm hoping you guys can steer me in the right direction before I pull my lower unit off again. Any suggestions?

 

[2cycle]

Re: Water Pump Woes

I looked at my Clymer manual and the water pressure spec for a 1988-on Merc 115 reads as 1-5 PSI @ 5000 RPM. It sounds like you are close or right at that. I've never had or worked on that model but on my older inline 6 water exits through the exhaust (which made me think I had done something wrong when installing the impeller only to learn that it is designed this way). Hopefully someone will be able to give you some more precise direction. Good luck!

 

[andrewkafp]

Re: Water Pump Woes

I think the water pressure should be closer to -10-15 PSI on the big 6. My 50hp runs at about 5-6psi about 4500 rpm. That water coming out everywhere is probably more related the the hose pumping water in through the pickup (You don't see it when submerged), rather than a bad seal. Was the impeller, the type that had the vanes bent in one direction ? Is it installed the right way? When you say 5 PSI at WOT, was that at normal running temperature on the water or on the muffs ?<br />BTW Is your gauge reading correctly ? Is the stream too hot to touch ?<br /><br />Great pictures of the L/U.. Promptly saved in my collection.

 

[Fishallot]

Re: Water Pump Woes

A little more info.... This motor is a 115 4 cyl., I was expecting the water pressure to be closer to 10 -15 psi. <br /><br />I can clearly see water coming up from where the shift shaft enters the lower unit, it's coming out with some pressure rather than ust flowing out. All that water falling down the cavatation plate is coming from there.<br /><br />The pressure gauge reading I got was from running the boat in the water after idling for a good 20 minutes.<br /><br />This afternoon I pulled the gauge from the dash and tried to check it. I sprayed a garden hose into the fitting on the back of the gauge and it definatly registered pressure. It seemed to work well throughout the pressure range. I got it all the way up to 30 psi.<br /><br />Here's a pic of my old impeller. It was in decent shape other than the rubber being somewhat soft.<br /><br />

<br /><br />The tell tale stream I'm getting now looks weaker with the new impeller than what I was getting with the old impeller. It's also taking a little longer to start pumping out water.<br /><br />Another thought I had tonight... could it be that the water tube seal didn't seat right when I put the lower unit back on? When I removed the lower unit the water tube seal didn't come out with the pump housing. Since the upper part of it looked to be sealed well I figured I'd be better off leaving it alone and not pulling it out. I did rub some 2-4-C inside the tube before sliding everything back together.<br /><br />I'm sure that i'll be pulling the lower unit back off in the next few days. I was just hoping you guys could tell me what I did wrong and what to look for.<br /><br />BTW... If you look at the pic I posted of my water pump and the lower unit that black silicone is what I didn't replace. I did scrape and redo the lighter colored silicone at the base of the water pump. <br /><br />Thanks in advance for any additional help on this. As soon as I get this water pump right i'll be rebuilding my fuel pump and may need some additional help.

 

[andrewkafp]

Re: Water Pump Woes

Keep bumping up your post.I am not a real expert on these things, having only owned a Merc for 1 year however there are members like Rodbolt, Clams, JB and KClost to name a few that have had a lot of experience with Mercs and must have come across this situation before.

 

[rodbolt]

Re: Water Pump Woes

hello<br /> I will try to look out in the shop for the correct manual. did you check the t-stat and pressure valve and diaphram? dont get to wrapped up with water coming out of the shift shat area. its kinda normal. did you replace the entire kit or just the impeller? and I think the black rubber face seal may be missing from your pump. there again it may not have one. check that the pressure valve and t-stat are in good working order. if they are not you will never have pressure.<br /> good luck and keep posting

 

[KCLOST]

Re: Water Pump Woes

Did you buy an entirely new kit for the pump, or did you just replace the impeller? <br />The reason I ask is because I'd like to know if there was a guide tube/seal to help align the pump housing tube with the tube that goes up to the block... I believe you want to put that seal on the pump housing tube before reinstalling the lower unit. If you left it on the tube that goes up to the block, you may have a bad connection...<br /><br />I don't think you should see much water (if any) coming from those areas. When I run my motor on muffs, I only get water out of the prop and pee hole, and a little that squirts out of the muffs... It leads me to believe that you are not getting all the water to the head. Thus it fills in the housing and has to go somewhere?????? Is the water leaking around those areas cold? And how about the temp. of the water exiting the prop and pee hole.<br />Also what kind of water pressure do you have coming out of your garden hose? Is there any chance you are forcing too much water in? Worth asking anyway <br />We will get it figured out!!!!

 

[Fishallot]

Re: Water Pump Woes

Thanks for the replies. <br /><br />I replaced the t-stat and poppet diaphram a few months ago. I did install the water pump kit, not just replace the impeller. The kit had in it's contents a new housing, impeller, wear plate and a couple gaskets... thats it. It was a Quicksilver kit.<br /><br />My gut is telling me that my water tube seal isn't seated right and combined with the fact that I didn't silicone the exhaust chamber it's letting water go everywhere except where I want it. <br /><br />When running on the muffs I barely open the hose up, I'm sure it's not getting too much pressure from it.<br /><br />I guess I'm going to go pull the lower unit back off right now and see if I can notice something that isn't right.<br /><br />I'll let you know what I find.

 

[quantumleap]

Re: Water Pump Woes

I just did the same service on my 97 125. You do have to have the bead along the exhaust chamber, but your problem looks moke like the water tube didn't seat correctly. Did you have to pull the tube off of the upper fitting or did it come out on the tube when you dropped the unit? Also you state that you put sealant on the back of the housing. You shouldn't need any sealant on the gasket. Did you put sealant on the tube at the cover? It looks like the tube isn't attached and your pump is filling the lower leg with water(as well as the exhaust). Drop your lower unit and I'm sure the problem will be evident. Obviously there is no remedy without dropping the unit. Good Luck.

 

[Fishallot]

Re: Water Pump Woes

I just dropped the lower unit and inspected everything. I didn't really find anything that looked out of order so I re-installed it as is. This time I did run the bead at the edge of the exhaust chamber, I went from one side of the lower unit all the way to the other. I also pulled the water tube off the upper fitting this time and put it on the pump housing before I put everything back together. Do the water tubes wear out over time? I wouldn't say it was loose on the housing but the seal didn't seem to be as tight as the seal b/n the tube and the upper fitting when I pulled it off. Everything slid back in on the first try this time so I feel confident that the water tube is lined up on both ends.<br /><br />I'm reluctant to fire the motor back up now until the silicone has had a chance to setup. I guess I'll give it a try tommorrow after work and keep my fingers crossed.<br /><br />Thanks for everyones help, i'll let you know how it turned out.

 

[Fishallot]

Re: Water Pump Woes

I guess you could say I'm a glutton for punishment. I couldn't stand it not knowing if I had fixed the problem or not so I just fired her up and the problem is still there. <br /><br />Here's a pic that clearly shows the water coming up through the shift shaft.<br /><br />

<br /><br />I just reread all the replies to my post so far and something just caught my eye. Someone stated that I shouldn't have used any silicone on the water pump gaskets, well I did. I used Permatex #2 on both sides of all the gaskets. Could this be causing a problem?<br /><br />I'm at a loss as to what to do next. I really don't want to pull the lower unit again until I think I know what the problem is.

 

[KCLOST]

Re: Water Pump Woes

I'm a bit confused on this one....<br /><br />But I have to ask this..... If you look at your pic of the impeller when it is in the housing, are you completely sure that you intalled the impeller in the same orientation? <br /><br />The old impeller is installed correctly, by the way, and it doesn't look to bad... It has me wondering if there is something else going on here...<br />We really need the serial# for your motor to confirm what the pump has, but I THINK is has the following...From top to bottom....<br /><br />SEAL (for tube)<br />WATER PUMP HOUSHING (24C w/teflon applied underneath the housing)<br />KEY & IMPELLER <br />GASKET <br />FACE PLATE <br />GASKET (different than the above gasket)<br /><br />And screws to mount housing of course...<br /><br />Do you have all this stuff? Meaning, all of the above should be stacked on top of each other (so to speak)? Is the face plate oriented properly (not upside down)? But give us the serial # to confirm...

 

[Fishallot]

Re: Water Pump Woes

I'm positive I installed the impeller correctly. I tried putting it on like the manual said, impeller first then sliding the housing down the shaft over it while turning the shaft, and I couldn't get the impeller tines to bend into the shaft. I ended up taking the impeller back off the shaft and installing it into the housing then I slid them both back on the shaft as one unit. Before I put it on I laid it right next to the old one to make sure it was in correctly.<br /><br />The old impeller was working but it wasn't registering much pressure on my gauge. When I bought the boat last Fall the old owner said he had owned the boat 5 years and had never replaced the water pump so I knew it should be done. The rubber on the old impeller was soft when compared to the new one. It had also taken a set. After 2 days in the trash can the tines are still bent over. I know that my old water pump wasn't leaking water out of the housing like it is now so this has to be something that I screwed up.<br /><br />My motor serial number is OD190240. I just went and dug the new pump kit box out of the trash can, the Quicksilver part number on it is 817275A 2. It had everything on your list except for a new tube seal. I installed all the new stuff exactly like the old parts were, just like you listed.<br /><br />Thanks for the help on this. I know it has to be something simple that I did wrong.

 

[Fishallot]

Re: Water Pump Woes

Any other suggestions before I pull the lower unit off again, tear everything down and start over? I'm sure i'll have to buy new gaskets as the permatex has probably set up by now. Think i'll see if I can buy a new water tube to make sure the seal is good.

 

[kozman01]

Re: Water Pump Woes

Not to get too much off subject here, but where do you need to apply a silicone bead before reattaching the LU. I'm getting ready to put my LU back on and don't want to miss anything. My exhaust "port" has a rubber gasket, do I still need to silcone around that? There wasn't any when I took the LU off. Thanks!

 

[KCLOST]

Re: Water Pump Woes

Fish,<br />Remove the lower unit....<br />After that let's just do something first, it might help. <br />Remove the poppet assembly and the t-stat...<br />Take your garden hose and shove it into the t-stat hole, this will flush the water jacket area at the cylinder head.... Do that for a while then go ahead and move the hose to the poppet opening (watch the grommet and carrier that could be in the hole, don't lose those). Flush it for a while....<br />The whole time while doing this, place a bucket under the drive shaft housing, and see if anything comes out... You "may" just have a blockage somewhere... I hope this helps...<br />Also, I would call Mercury on this one.... I'm not completely sure if your water leak is common on this motor or not. Asking won't hurt...<br /><br />I'm still with ya, let us know....

 

[SingleShot]

Re: Water Pump Woes

I've got the 125, I think their the same motor just different boreing in the cyl. Mine doesn't leak like yours on the muffs. Keep us informed on what you find.<br /><br />GOOD LUCK<br /><br />Singleshot

 

[Fishallot]

Re: Water Pump Woes

I may have stumbled into something this time. <br /><br />I pulled the lower unit again and started to take your advice about pulling the t-stat and poppet valve. Since I didn't have a new gasket for those two I tried going at it a different way. I took the open end of the garden hose and pushed it up against the copper water tube where the top of water tube seal hooks into it. Water started filling the motor and eventually it flowed freely out of the tell tale hose. I'm assuming this means there's no blockage? When I looked back down at my garden hose I noticed that water was rapidly exiting the motor back down the area that the drive shaft goes up into the motor. This made me remember something that I should've said from the beginning... when I originally pulled the lower unit there was no rubber seal or nylon spacer on the top of the drive shaft. I just looked in my manual and they mention these two items for the larger motors but not for my 115. Should these two items have been on my shaft when i pulled it? Could they possibly be stuck up inside the motor? I looked up there with a flashlight and couldn't really see anything that resembled them. Would not having them on my drive shaft cause water to come back down to the top of my lower unit and exit anywhere it can?<br /><br />At least now I think I may have figured out where the water is coming from. Sorry this has been so difficult, it never seems to fail that when I take on a project it never goes smoothly.

 

[Fishallot]

Re: Water Pump Woes

I did a little more investigating on exactly where the water is coming from. I started pumping more water up the water tube with my garden hose and looked up the drive shaft cavity with a flashlight. On the topside of the cavity, which would be the rear of the cavity if the motor was tilted down, there's a hole that leads into the cavity that has the copper water tube in it. The water is coming out of that hole. Is it possible that my water tube came disconnected up at the top where it goes into the motor? I'm assuming the only way to check to see is to pull the mid section of the motor off? Is this a major undertaking or fairly simple and straight forward?<br /><br />I've left the lower unit off the motor this time in hopes of correcting this problem before putting it back on.

 

[Fishallot]

Re: Water Pump Woes

Now I'm really feeling dumb. <br /><br />I just realized that the reason water is coming from that hole is because I was pumping it up there. My garden hose is larger than the water tube so I pushed it all the way to the rubber grommet that the water tube goes through. I'm sure that I was pushing water up the cavity that the water tube is in.<br /><br />Now I'm back to square one. My gut is telling me that my water tube seal is leaking where it meets the pump housing. How crazy would it be to try putting silicone on it?