Mercury I6 Water Jacket Cleaning after impeller replacement

[V20Pilot]

On a previous thread I had created I had questions about getting the cover off the water jacket. Okay so I have the cover off now and have one of the pieces of the impeller. removed. There should be yet another section of the impeller still hiding down where I found the one or I'm guessing it may be down in the tube coming from the top of the pump housing. Here is a photoof the impeller and the vane that had broken off. Note on the impeller there is yet another vane which has a nice chunk ripped off of it. So guys in my group here in DE have suggested maybe it disintergrated. I'm not betting on it.
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I'm curious on the best way to clean out the inside of the water jacket. I know Permatex makes a spray on stuff for helping get what is left of the gasket off but what about the corrosion on the aluminum? Is there a chemical that can eat this crap from inside or is this better being attacked with a wire wheel on a drill?​

When it comes time to reassemble it was recomended I use a Permatex lane: product on the *new* SS bolts rather than never-sieze, but what about the new gasket? Permatex (the old brown/black stuff {I hate using that crap} or is there something newer and better? ???

Steve

 

[kungpaoshizi]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

Muriatic maybe? Maybe vinegar and elbow grease will take off the corrosion..

 

[emckelvy]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

You can wire-brush the loose deposits on the cover and accessible areas of the block. Vinegar might help, also some of those "purple" spray cleaners that are alkaline-based would probably eat away or at least loosen some of the deposits. The stuff, if left on too long, will also "eat away and loosen" paint and aluminum so just be careful with any chemicals!

Good 'ol mechanical scraping ain't pretty or easy, but usually does the trick. From what I can see in the pic, the block doesn't look too bad and the deposits around the cylinders aren't so much that they'd affect heat transfer.

On the flat gasket-sealing surfaces on block and cover, a gasket scraper does a good job. You could use some gasket-remover spray to loosen them up first, but that stuff also eats up paint so be careful with it.

A razor-blade-type scraper works well for scraping the embedded gaskets, I picked up an inexpensive one at Wal-Mart with replaceable blades, and it does a great job.

Since you have no great love for Permatex No. 3, you might try Permatex/Loctite 518 anaerobic sealer. It only cures where it's squashed by a gasket surface, the rest washes away harmlessly.

Note that most of the new Mercury gaskets have a shiny coating of sealer already sprayed onto them, in your gasket comes like that, you don't really need to use any extra sealer.

The exception to that would be if the machined surfaces at the top of each cylinder are eaten away. Very common to see this, and if so, causes sealing problems.

In that case, the Loctite 518 would work will at filling small gaps. But for larger erosion, try some red Hi-Temp RTV. Just don't use a ton of it, 'cause it will squeeze out and harden. Sometime in the future, chunks of RTV could break off and potentially clog the cooling system.

One last thought, if you're suspicious of more chunks o' rubber in the cooling system, you might try running water up the copper water supply tube (pull the lower unit as necessary), while the back cover is off. It'll move a lot of water thru the motor and you'll get a pretty good idea if you have good circulation. And it might flush any stray bits of impeller that remain.

HTH.........ed

 

[belairbrian]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

I've used aircraft stripper on aluminum car valve covers. You can find it at most automotive parts stores.

 

[Faztbullet]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

CLR works good too.....

 

[V20Pilot]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

You can wire-brush the loose deposits on the cover and accessible areas of the block. Vinegar might help, also some of those "purple" spray cleaners that are alkaline-based would probably eat away or at least loosen some of the deposits. The stuff, if left on too long, will also "eat away and loosen" paint and aluminum so just be careful with any chemicals!

Good 'ol mechanical scraping ain't pretty or easy, but usually does the trick. From what I can see in the pic, the block doesn't look too bad and the deposits around the cylinders aren't so much that they'd affect heat transfer.

On the flat gasket-sealing surfaces on block and cover, a gasket scraper does a good job. You could use some gasket-remover spray to loosen them up first, but that stuff also eats up paint so be careful with it.

A razor-blade-type scraper works well for scraping the embedded gaskets, I picked up an inexpensive one at Wal-Mart with replaceable blades, and it does a great job.

Since you have no great love for Permatex No. 3, you might try Permatex/Loctite 518 anaerobic sealer. It only cures where it's squashed by a gasket surface, the rest washes away harmlessly.

Note that most of the new Mercury gaskets have a shiny coating of sealer already sprayed onto them, in your gasket comes like that, you don't really need to use any extra sealer.

The exception to that would be if the machined surfaces at the top of each cylinder are eaten away. Very common to see this, and if so, causes sealing problems.

In that case, the Loctite 518 would work will at filling small gaps. But for larger erosion, try some red Hi-Temp RTV. Just don't use a ton of it, 'cause it will squeeze out and harden. Sometime in the future, chunks of RTV could break off and potentially clog the cooling system.

One last thought, if you're suspicious of more chunks o' rubber in the cooling system, you might try running water up the copper water supply tube (pull the lower unit as necessary), while the back cover is off. It'll move a lot of water thru the motor and you'll get a pretty good idea if you have good circulation. And it might flush any stray bits of impeller that remain.

HTH.........ed

Thanks a bunch Ed and you other guys.

I was able to get the cover off by heating the bolts. Five had the heads break off but four of them I was able to work out with heat and vice-grips. The last one I had to drill out the bolt and I installed a heli-coil. My what a wonderful invention that is.

I used a wire brush on an air drill and cleaned up the inside of the cover pretty good and inside the block as best I could. I double checked all the bolts going into the threaded holes and chased them out as most of them had a large about of corrosion in them. The bolt holes in the cover had a fair amount of corrosion too and I just chased them out with a drill bit. I also double checked the alignment of how well I centered the hole for the heli-coil and had all the bolts in the cover. Air ratchet sure comes in handy for things like that. So now I'm ready for final assembly. I get the block all coated with a fine coating of RED RTV and grabbed the gasket. WTF the gal at Almar's sold me the wrong one. I'm guessing there must be a inline six just slightly small than mine. Maybe 75 or 90 HP or something. Or a 115 HP with less space between the cylinders. I measured the #1 and #6 spark plugs center to center and then the gasket. My motor I get 17" the gasket is 16 1/2". So I have to wait for them to order the right one. I asked if the folks they buy it from could check the gasket measurement before they ship it and advised they would not do that. Next time I'll buy it on line and I'll have a spare gasket for next time.

I didn't get any photos during this last day of work but I'll U/L some this week before I finish.

Steve

 

[emckelvy]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

Strange, all the 99-c.i. blocks have the same spacing back there.

This is what they should have sold you:

Mercury Quicksilver 27-98185 3 - Gasket @ MarineEngine.com

 

[V20Pilot]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

Strange, all the 99-c.i. blocks have the same spacing back there.

This is what they should have sold you:

Mercury Quicksilver 27-98185 3 - Gasket @ MarineEngine.com

Yes, the correct one finally arrived yesterday. I had time today after work to get it all back together and do a test run. The tell-tale is still not sending a constant flow out the hose. I checked the temps of the different cylinders and it seems the #1 and #6 are both at about the same temp (136-139). This is with the tach readng 1000 rpm. Before the #1 was running over 150.

Back up a couple of days. When I didn't find the second piece of the rubber from the impeller I took the lower unit down again while I was waiting for the correct gasket to arrive. No Joy! I was hoping I'd find it in the tube rising up from the pump housing. Is there somewhere else I could look? I noticed holes exiting into the port side. I believe that would be the exhaust manifold correct? I wouldn't think water would exit to the exhaust and then come back into the water jacket does it? I'm just trying to brainstorm any ideas of where the other piece of the impeller could have gone and could it be causing the reduced flow out the tell-tale. Oh, and yes I did verify the fitting at the top of the jacket an the rubber hose were clear.

I may go run her in the water in the next day or two and see how she does. Let me know what ya'll think.

Thanks in advance guys,

Steve

 

[snowbrd84]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

I had to replace the impeller on my last engine right after i bought it due to high temp alarm. No change, still got the alarm. Pulled the lower unit and stuck the hose in the thermostat housing, nothing would come out the motor leg water tube. Pulled the head, almost all of the water jackets were full of sand and the chewed up old impeller... blew it all out with compressed air, put it back together and it worked perfectly. You may have a good deal of the water jackets clogged with debri or buildup, but some water gets through, so only the areas where the water gets through are coooling...

 

[V20Pilot]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

I never got a hi-temp alarm. I'm not even sure if I have one. Does anyone know if the I6 115HP has a temp alarm (1985)? If it does what temp would the alarm be set to alarm at? My problem is insufficient water flow out the tell-tale (AKA pisser). A more knowledgable wrench on another reply recomended putting a low pressure gauge on the cover plate. Proper pressure should be about 7-9lbs. Question is hmmm maybe this should be a new thread... Look for "poor water flow problem from Tell-Tale I6 115hp Mercury". Maybe I'll start on with the temp alarm question too.

Steve

 

[jimmbo]

Re: Mercury I6 Water Jacket Cleaning after impeller replacement

No temp alarm on thses engines