Is RTV or a sealer only used reinstalling the lower-unit vs the water-pumps housing i

[wickware]

1. Is RTV or a sealer only used reinstalling the lower-unit vs the water-pumps housing if no gasket is used (when replacing the impeller on a 1970 35HP Chrysler)?

2. One set on instructions mentioned coating the water-pump?s housing screws with RTV (I feel due to corrosion but I?m in fresh water but will coat them). I have not seen any instructions on using a sealer to install the housing w/o a gasket. Please see all parts in attachment.

3. I feel I?m seeing a slight sign of a sealer on the housing and plate but not an RTV type or gasket.

4. It?s time to put the Monster back together vs letting time slip upon me.

Thanks for your advice in advance.
JOW

 

[Frank Acampora]

Re: Is RTV or a sealer only used reinstalling the lower-unit vs the water-pumps housi

It is not necessary to use any sealer on the pump housing. I personally use anti-seize on the mounting screws. I have seen RTV used and it does a good job of preventing corrosion and snapped mounting bolts/screws. Even in fresh water, use something on the screws-- because of the different metals, corrosion will always be somewhat of a problem if not addressed.

 

[wickware]

Re: Is RTV or a sealer only used reinstalling the lower-unit vs the water-pumps housi

Thanks Frank! We Appreciate Your Experience And Sharing. Are today?s impellers that fragile that they need checking yearly and replaced every 2-3 years (vs my last checked 1985 impeller that was not having or showing a problem in my opinion)?

Thanks & Take Care!
JOW

 

[Frank Acampora]

Re: Is RTV or a sealer only used reinstalling the lower-unit vs the water-pumps housi

If the prop is spun, I seem to remember that the hubs are no longer made. So: you will need to either get lucky and find a prop shop with a hub laying around, or buy another prop. The third option would be to "pin" the hub. Drill through the hub and inner aluminum of the prop in three places. Press in three 3/16 pieces of brazing rod. It is strong enough for normal loads but should shear if you hit something.

Water pump impellers are very "iffy." The original on my 55 lasted about 15 years and I have had others that lasted longer than three years, but this is a case where you can never be too safe. It only takes 30 seconds of abuse to ruin an impeller. The fuss of checking and the cost of replacement is well below the damage and aggravation caused by overheating.

I noticed that in one of the photos, there is a broken bolt for the rear of the exhaust snout. There is nothing behind this area, so you have the option of drilling carefully and rethreading to original size, OR you can drill to clear a bolt and use a self locking nut inside, or you can drill and tap oversize. If you want a new exhaust snout, try franzmarine@aol.com. If it is silver-grey, rather than normal aluminum color, it is a zinc anode. do not paint it.

Ah crap! I'm getting old. Either that or I work too many hours. The last paragraph was intended for Fishmonger-- 50 running slow. I guess I can't spell alzheimers

 

[wickware]

Re: Is RTV or a sealer only used reinstalling the lower-unit vs the water-pumps housi

Documenting with a digital camera is good for the records, ?bad mind? and possibly spotting problems.

1. I have documented installing a new impeller with the vanes in the correct positions (related to the old).

2. BUT! I feel at some point the old impeller?s vanes were changed due to the shape of the old vanes.

3. Is A-Rule-Of-Thumbs, the impeller, driveshaft and propeller should turn clockwise with the boat traveling forward?

4. Most of all, I installed the vanes in the same direction of the recent set ?since they were working".

JOW

 

[Frank Acampora]

Re: Is RTV or a sealer only used reinstalling the lower-unit vs the water-pumps housi

Yes, engine turns clockwise, looking from the top, when running. Your old impeller is typical of an old impeller that has taken a set. While it does not appear to have much wear, there is still the possibility of vanes breaking off. Better to have changed it and be safe.