1964 Mercury 500 50hp 4 cyl 2 stroke, where to begin

R

robmsz

Cadet
Joined
May 25, 2017
Messages
11
1964 Mercury 500ES 50hp 4 cyl 4 stroke serial number starts with 171 (off the top of my head), where to begin?

My buddy picked up this motor at a garage sale, he had the same motor stolen years ago, the same way (cables hack sawed), we highly suspect it's the same motor. In any case we'd like to resurrect it. We don't even know if it runs yet, what would be the best course of action before we sink tons of money into it. He says the lower unit is leaking oil, wouldn't it make more financial sense to see if it runs first before replacing the seals in the lower unit (that we can't find)?
 
Last edited:
CaptnKingfisher

CaptnKingfisher

Petty Officer 1st Class
Joined
May 14, 2017
Messages
259
Yeah you can check for spark and check your compression and from there you'll get an idea of how much or how little this motor needs. I would do that before ghost hunting a lower unit seal.
 
6

60sboater

Petty Officer 1st Class
Joined
Jun 18, 2015
Messages
307
Yes,do all the basics up top first since that's the bigger potential money pit.
 
1960 Starflite

1960 Starflite

Petty Officer 1st Class
Joined
Jun 23, 2011
Messages
352
Are you sure it's a "4 stroke", I'm not. I have a 1965, 650 4 cyl, 2 stroke. First off, it has a magneto and you'll have to pull the mag off to clean and reset the point gap. Second, the carbs will be dried out and need cleaned/rebuilt/floats set. Third, the fuel pumps and hoses will need replaced/rebuilt. Lower unit "leak", it will need to be removed to replace/rebuild the water pump. You HAVE to have the water pump working before starting engine anyway.

Maybe not be worth the $$$ "financial sense". But if you want it, Do it :) Yep, I did the same thing :)
 
GA_Boater

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Changed the title to 2 stroke.

With a motor that's been sitting for a while as yours has, the compression PSI isn't as important as even compression. The rings dry out and can stick some and adding some oil through the plug holes will lube the walls and rings. Look for compression numbers within 10 percent.

My motor, the same as yours and sitting for years, only had 50-55 PSI cold. She runs like a top after fixing wiring and rebuilding the carbs. Someday I'll look at the compression again, but she runs great.
 
R

robmsz

Cadet
Joined
May 25, 2017
Messages
11
1960 Starflite said:
Are you sure it's a "4 stroke", I'm not. I have a 1965, 650 4 cyl, 2 stroke. First off, it has a magneto and you'll have to pull the mag off to clean and reset the point gap. Second, the carbs will be dried out and need cleaned/rebuilt/floats set. Third, the fuel pumps and hoses will need replaced/rebuilt. Lower unit "leak", it will need to be removed to replace/rebuild the water pump. You HAVE to have the water pump working before starting engine anyway.

Maybe not be worth the $$$ "financial sense". But if you want it, Do it :) Yep, I did the same thing :)
Click to expand...



We posted at the same time, great info, I'll post again when we get that far.

Thank You.
 
R

robmsz

Cadet
Joined
May 25, 2017
Messages
11
GA_Boater said:
Changed the title to 2 stroke.

With a motor that's been sitting for a while as yours has, the compression PSI isn't as important as even compression. The rings dry out and can stick some and adding some oil through the plug holes will lube the walls and rings. Look for compression numbers within 10 percent.

My motor, the same as yours and sitting for years, only had 50-55 PSI cold. She runs like a top after fixing wiring and rebuilding the carbs. Someday I'll look at the compression again, but she runs great.
Click to expand...

I just asked and you are correct Sir, it is a 2 stroke, my bad, thanks for moving this thread. Thanks for the information. It appears that we have the same '63-'65 engine. I'll update on the progress.
 
GA_Boater

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Mine is a new one, 1966. LOL

Still the same mechanically, only cosmetic decal differences.

Most of the parts are still available with some searching. Be very careful with the magneto - Those parts are really hard to find and expensive. Rotor and cap are worth their weight in gold!
 
R

robmsz

Cadet
Joined
May 25, 2017
Messages
11
GA_Boater said:
Mine is a new one, 1966. LOL

Still the same mechanically, only cosmetic decal differences.

Most of the parts are still available with some searching. Be very careful with the magneto - Those parts are really hard to find and expensive. Rotor and cap are worth their weight in gold!
Click to expand...


"A new one...." Too funny!

On a serious note, Besides the magneto, cap & rotor being worth its weight in gold.....so is this forum!

Thank you guys for the continued information !!!
 
R

robmsz

Cadet
Joined
May 25, 2017
Messages
11
Today we popped off the flywheel, the timing belt is snapped. The belt is a Kierhaefer 31112 (original belt?), I looked on the net and found one on Ebay, it says "temporarily out of stock", does anyone know where I can find an OEM or cross referenced belt? A Mercury 20140 keeps popping up would that be the replacement?
 
Last edited:
R

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,269
The same belt fitz all of them 3 cylinder / 4 cylinder / 6 cylinder .----------From the 1950's to the late 1970's.
 
R

robmsz

Cadet
Joined
May 25, 2017
Messages
11
OK, We're as far as getting the motor & starter to spin. Getting no spark, does anything need to be energized? As I said before we think this is the same motor that was stolen from us 40+ years ago so the thick power plug cord was cut and two wires that we touch acting as a key but no spark still..

Any Ideas ?
 
Last edited:
R

robmsz

Cadet
Joined
May 25, 2017
Messages
11
We had no spark because the cable was lopped of and had six wires hanging. We are getting spark now and working on the lower unit. We had to drill out the bearing ring and used a wheel puller with chains and hooks attached. I wish I would have taken a photo of that! One hooked was an S hooked crimped in a vice to make it fit, the other one was an "I" bolt (the adjustable one) ground into a hook. He just found a second 500 for $50 he's picking up today, judging by the color it looks around the same year. the guy says the power head was re-done four years ago. He said he stripped the fly wheel nut. Don't really know how because I haven't seen it yet but he needed the controls so the rest is a bonus. Maybe we'll have a running one by first freeze on Lake Erie for some Walleye, more updates to come. Here's the first motor
 
Last edited:
You must log in or register to reply here.
Top