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Water Impeller Housing Trouble
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Author:  dbird [ Thu Apr 07, 2011 12:22 pm ]
Post subject:  Water Impeller Housing Trouble
Gents, I'm looking for some help. I have a 93 Vista with the 5.8 and King Cobra Drive. This will be the third year in a row that I have had to replace the impeller housing. Water is apparently not getting to the impeller/housing soon enough, the whole thing heats up, and the metal "cup" inside twists. This subsequently pokes through the housing and results in a $154 piece of plastic junk. I actually have someone help me to hold the muffs tight to the drive to ensure that all of the water is making into the lower unit and not blowing out the sides. At no point in time is the engine ever above idle. Am I missing something here, or should this housing really be made out of metal. BTW, the impeller itself looks perfect. (It ought to, its being replaced 4 times now in 3 years) I'm beginning to think that this thing should never be run on a hose and that being in the water facilitates flow due to the entire drive being under water. HELP!
Author:  taz42169 [ Thu Apr 07, 2011 1:04 pm ]
Post subject:  Re: Water Impeller Housing Trouble
You did use the glycerin gel that comes with the impeller, correct? Do you have any other way to get water to the engine except via the muffs? I know there is an inline adapter you can add which will allow you run your garden hose closer to the impeller.

Another technique I've used is start the engine, run it 20 seconds, shut it down, and wait a minute. Repeat until you see water start to discharge.

Hope this helps.
Author:  dbird [ Thu Apr 07, 2011 1:33 pm ]
Post subject:  Re: Water Impeller Housing Trouble
Thanks for the response. My impeller(s) have never come with the glycerine package you mentioned. The directions that came with the last one mentioned using a little bit of vaseline, which I did. Not sure if I can add the direct connection or not, but would definitely be interested. It is about a 2' ft lift from the muffs to the pump. I think I may just be better off not using the muffs at all, either rig up some kind of tank or only run the engine when the boat is in the water. I would estimate that the time from starting the engine to seeing water out the exhaust would at most be 10-15 seconds.

Thanks again
Author:  LouC [ Thu Apr 07, 2011 3:43 pm ]
Post subject:  Re: Water Impeller Housing Trouble
I've never had a problem running my Cobra on the muffs and the housings and impellers that I remove each year look like new. Are you sure that there is not any blockage in the water intakes in the lower unit, another possibility is that the water tube from the lower to the upper could have debris in it, or the seals on that tube can leak. There is also a vent hose on the impeller housing (at least on the standard Cobra there is) that has to be not clogged so the impeller can prime.

I do have to break up small barnacles that start growing in the water intakes, I remove the drive, take off the impeller, break the shells with a dentists pic, then hook up the muffs and blast em out....a yearly ritual in salt water....
Author:  ridepate [ Thu Apr 07, 2011 4:52 pm ]
Post subject:  Re: Water Impeller Housing Trouble
Todd,
Not trying to question your intellengence, but are you sure your twisting the impeller the right direction upon install??? Reg Cobra is clockwise, King is counter. That could explain the housing-wad-ups.
Author:  Winedown [ Thu Apr 07, 2011 5:30 pm ]
Post subject:  Re: Water Impeller Housing Trouble
ridepate wrote:
Todd,
Not trying to question your intellengence, but are you sure your twisting the impeller the right direction upon install??? Reg Cobra is clockwise, King is counter. That could explain the housing-wad-ups.


This may be a dumb question, but does it matter? There is no memtion in my manual (VP 5.0) of which way to install it. And it looks like it would right itself on the first spin. Is that not the case?
Author:  dbird [ Thu Apr 07, 2011 7:19 pm ]
Post subject:  Re: Water Impeller Housing Trouble
Thanks for all the advice. Ridepate and LouC might both be onto something. I have never checked for a blockage as it pumped water just fine once it got around to it. (Boat is trailered, not slipped by the way) As far as the direction of the impeller, I never checked it- just replaced it the way it came out. When you are holding the impeller housing with the open side facing you, the impeller vanes are leaning to the right. If indeed the King Cobra spins counter clockwise, this seems to me the impeller is in WRONG. (and has been for 3 years) To even further cloud the issue, it has NEVER had a problem with overheating. What tipped me off was water dribbling out from behind the housing.

And believe me, nobody is going to insult my intelligence- I'm always open to advice. :D
Author:  ridepate [ Thu Apr 07, 2011 7:50 pm ]
Post subject:  Re: Water Impeller Housing Trouble
dbird wrote:
Thanks for all the advice. Ridepate and LouC might both be onto something. I have never checked for a blockage as it pumped water just fine once it got around to it. (Boat is trailered, not slipped by the way) As far as the direction of the impeller, I never checked it- just replaced it the way it came out. When you are holding the impeller housing with the open side facing you, the impeller vanes are leaning to the right. If indeed the King Cobra spins counter clockwise, this seems to me the impeller is in WRONG. (and has been for 3 years) To even further cloud the issue, it has NEVER had a problem with overheating. What tipped me off was water dribbling out from behind the housing.

And believe me, nobody is going to insult my intelligence- I'm always open to advice. :D


Todd if the impeller vanes are leaning to the right, facing the housing-liner, Drive-side, it was installed correctly. In other words, it was twisted-in counter-clockwise. Follow me??
Author:  ridepate [ Thu Apr 07, 2011 7:54 pm ]
Post subject:  Re: Water Impeller Housing Trouble
Winedown wrote:
ridepate wrote:
Todd,
Not trying to question your intellengence, but are you sure your twisting the impeller the right direction upon install??? Reg Cobra is clockwise, King is counter. That could explain the housing-wad-ups.


This may be a dumb question, but does it matter? There is no memtion in my manual (VP 5.0) of which way to install it. And it looks like it would right itself on the first spin. Is that not the case?


Wine, It COULD right itself, but honestly I'm not sure it would. On my Cobra with the oval-shaped liner, I don't think it would, it would self-destruct I'd think.
Author:  dbird [ Thu Apr 07, 2011 8:33 pm ]
Post subject:  Re: Water Impeller Housing Trouble
Yup, now I'm stumped. I double checked the manual (and confirmed what Ridepate suggested) that the impeller as far as direction, was installed correctly. I would tend to think if there was a blockage, it wouldn't pump water at all, but dunno. At least I found the housing itself online for $36 so not all is lost. Any additional suggestions, keep 'em coming!!! Thanks
Author:  BoaterDan278 [ Fri Apr 08, 2011 7:26 pm ]
Post subject:  Re: Water Impeller Housing Trouble
With the impeller out and the cover off, if you hook up the muffs and turn on the water, how well does it flow through the housing? Dan
Author:  dbird [ Sat Apr 09, 2011 8:03 am ]
Post subject:  Re: Water Impeller Housing Trouble
Dan, thats a good idea, will try that on Monday. It has also crossed my mind that winterizing via pink stuff through the muffs may be the culprit. I'm wondering if that gravity fed hose from the tank can provide adequate flow. Either way, for several reasons I wont be using the tank to winterize again.
Author:  LouC [ Sun Apr 10, 2011 10:56 am ]
Post subject:  Re: Water Impeller Housing Trouble
dbird wrote:
Dan, thats a good idea, will try that on Monday. It has also crossed my mind that winterizing via pink stuff through the muffs may be the culprit. I'm wondering if that gravity fed hose from the tank can provide adequate flow. Either way, for several reasons I wont be using the tank to winterize again.

I have posted on this point many times DO NOT use that method, its risky and is really appropriate only for engines with closed cooling. Yes I know some have done it and never had a problem. Well if you read OMC's OE manual, they do not tell you to do that. They tell you to drain and leave it dry, or drain and back fill with AF. I think Merc says the same thing. Volvo does say you can use this method if you remove the thermostat, but I personally think their manuals stink, poorly translated and very vague.
I have replaced an impeller on my Cobra pretty much every season. I always run it on the muffs for tune up, etc and have NEVER had an impeller burn with good muffs and good water pressure. And, this is a salt boat, with some barnacle growth in the water intakes that has to be broken up each spring.

The only time I have heard of issues with Cobra impellers and housings burning, is when you use an aftermaket housing with an OE impeller, or vise versa, they do not fit the same. Use the whole kit from one manufacturer, OMC, or Sierra, do not mix parts.
Keep in mind, that an AF/water mix, is more dense than just water. That is specific gravity and that's what you measure when you check antifreeze protection. As such, it is harder for the impeller to suck this up than plain water and it's not under the kind of pressure that a hose provides. This is even worse on Volvos and Merc Bravos, the impeller is way up on the engine, the AF/water mix has to travel several feet to get to the impeller. On a Cobra or Alpha, the impeller is in the drive so it's not as bad, but still I say when winterizing, do it right and drain and back fill or leave dry....
Author:  dbird [ Mon Apr 11, 2011 10:04 am ]
Post subject:  Re: Water Impeller Housing Trouble
LouC, I agree with you 100 percent. Unfortunately, I didn't read the posts until AFTER this years incident. I am pretty sure I torched the housing in the fall both times while winterizing. The "tank" has been put in the yard sale pile. The new housing and impeller should be in tomorrow. I now have a set of manuals, and you are spot on about the instructions. BTW, the "OMC trained mechanic" in the area said he always uses the muffs and has "never had a problem". Ummm...... yeah. The boat will only see that shop as I drag it by on the trailer. Thanks
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