1965 Mercury 500 Lower Unit Catastrophy

[ssdale]

First post in this Forum

Last Fall I had my 1965 Mercury 500 on my restored 1965 McKenzie and hit a rock dike in the river. Although it shook the motor pretty hard, the only damage appeared to be a chip out of the skeg? (prop protector). We went directly to the dock and loaded up and winterized for storage. Well now upon inspection while in winter storage, I see that all the oil has ran out of the lower unit. The threaded piece is broken in two that holds all of it (propeller) in place and can be easily pulled out of the housing. The threads in the housing would appear to be ruined judging by the amount of material stuck in the threads of the broken piece.

Here is my question. Does anyone know a source on line where I can research exactly what years and models of Mercury used this same lower unit? Also mine is a short shaft. Does any replacement I find HAVE to be a short shaft? Sorry for such remedial questions. I am relatively mechanical, but I purchased the vintage motor in excellent shape because I just have not had any experience with them other than replacing an impellor. Totally restored the boat.

Any help would be appreciated. Thanks,
Dale

 

[Faztbullet]

Re: 1965 Mercury 500 Lower Unit Catastrophy

Units from 1965-1970 should fit but you have to look at them first as there was was design changes in shift shaft(square to splined) mounting stud width, driveshaft bearing(roller to cone) as this limits you from swapping a shaft if need be.

 

[racerone]

Re: 1965 Mercury 500 Lower Unit Catastrophy

Sounds like there was water in the lower unit that froze.----The extra pressure pushed the retainer nut out.------Look on E-bay for a replacement.

 

[ssdale]

Re: 1965 Mercury 500 Lower Unit Catastrophy

I could see how freezing could happen, but this is definitely result of impact. Is there any place that would know for sure what models/years would work? Elsewhere on the web, there are a lot of opinions, but few facts. When I went to our local outboard store, the parts kid just said that they really couldn't help with something that old.

Thanks,
Dale

 

[racerone]

Re: 1965 Mercury 500 Lower Unit Catastrophy

Hard to find a 25 year old with 40+ years experience.----------Many newer years will fit.------Get the facts at -----johnsoldmercs------Lots of knowledge gathered there.

 

[ssdale]

Re: 1965 Mercury 500 Lower Unit Catastrophy

Sounds like there was water in the lower unit that froze.----The extra pressure pushed the retainer nut out.------Look on E-bay for a replacement.

You were correct Racerone. I took the unit off and water followed by 2 ice cubes came out. Maybe the impact caused the leak or maybe had nothing to do with it. Broke the nut and the bearing carrier which are still available, but did not break the case. Not sure if the case threads are ruined until have A chance to clean up. I had no idea that you had to be so vigilant with regard to inspecting the oil in the lower unit. Posting this partially so other newbies will see.

 

[Chinewalker]

Re: 1965 Mercury 500 Lower Unit Catastrophy

Particularly on those older Mercs as they used carbon steel shafts that were prone to rusting, particularly at the seal areas around the propshaft and driveshaft (under waterpump).

 

[bgc]

Re: 1965 Mercury 500 Lower Unit Catastrophy

View attachment 224983

You were correct Racerone. I took the unit off and water followed by 2 ice cubes came out. Maybe the impact caused the leak or maybe had nothing to do with it. Broke the nut and the bearing carrier which are still available, but did not break the case. Not sure if the case threads are ruined until have A chance to clean up. I had no idea that you had to be so vigilant with regard to inspecting the oil in the lower unit. Posting this partially so other newbies will see.

I have been in the habit of changing the lower oil several time per season and during winterization. Oils cheep compared to lower unit…. I hope your able to get her sea worthy soon.

 

[ShowMeGuy]

Re: 1965 Mercury 500 Lower Unit Catastrophy

I have a parts merc 850 over here that you are welcome to check out. Just pm me and I can get you want ever question you have about it. I cant say it will or won't work unfortunately.....

 

[racerone]

Re: 1965 Mercury 500 Lower Unit Catastrophy

????The 850 lower unit is way to big, will not fit , not even close.

 

[oldman570]

Re: 1965 Mercury 500 Lower Unit Catastrophy

You can contact the following salvage yards and they may have a LU for your motor or have the parts that you might need. There is a listing for a 1965 LU on Ebay that you can check on, if you have not found a LU already.

Salvage yards:
sea-way.com
outboard-parts.com
laingsoutboards.com
tcoutboard.com
fairwindsmarina.com
salvagemarine.com
marinepartsoutlet.com
Superior Marine (800-338-9281)
trixieslanding.com Trixie’s Landing, Bayville, NJ 732-269-5838
americanoutboard.com
piratemarinesalvage.com/
Don's marine Salvage, 5601 126th Avenue North Clearwater, FL 33760 - (727) 576-8577
timsoutboard.com
Shipwreck Marine Recycling Used boat parts Rancho Cordova
M&M Marine Salvage...your source for boats and quality used boat parts!
http://www.outboardjunkyard.com/snow...BOUT-US-02-04/
http://forums.iboats.com/johnson-evi...e1-438822.html
Hope the best for your needs. JMO
Oldman570