Kola16
Petty Officer 2nd Class
- Joined
- Jun 23, 2019
- Messages
- 179
Hello all I bought a boat with a 1976 Mercury 500M 50 HP 2-stroke 4 cylinder manual tilt with serial number 7080037.
I plan on selling the engine for a bigger one, but I want to make sure I have the engine in good working condition before I sell it. I have done all the typical tune ups, like new plugs, lower unit oil, impeller, draiining old gas, etc. I have also replaced the starter solenoid and rebuilt the starter. The engine has great compression and the engine runs great as far as I can tell. Starts right up for a 2-stroke, choke works, pumps water, great compression on all 4 cylinders, gets out of the hole on the 18' aluminum bass boat and the entire works. No issues I think.
The problem is that i found this part that has a broken wire. I am not sure what its purpose is. the part number is 58124A20 ("switch assembly") and it has two wires coming off of it. One looks grounded, and the other is broken off. Picture below.
The broken off wire is black that leads to a yellow wire with a red stripe (Start Switch to Start Solenoid to Neutral Start Switch, maybe? found online I do not know what that means), which leads to an orange wire which connects to the "switch box assembly" then goes somewhere I cannot track it to.
My question is what does this part do? It is called a switch assembly, but switch for what? The engine functions flawlessly as far as I can tell so I am at a loss haha.
It is part number 26 on the diagram below.
Thanks for any help!
I plan on selling the engine for a bigger one, but I want to make sure I have the engine in good working condition before I sell it. I have done all the typical tune ups, like new plugs, lower unit oil, impeller, draiining old gas, etc. I have also replaced the starter solenoid and rebuilt the starter. The engine has great compression and the engine runs great as far as I can tell. Starts right up for a 2-stroke, choke works, pumps water, great compression on all 4 cylinders, gets out of the hole on the 18' aluminum bass boat and the entire works. No issues I think.
The problem is that i found this part that has a broken wire. I am not sure what its purpose is. the part number is 58124A20 ("switch assembly") and it has two wires coming off of it. One looks grounded, and the other is broken off. Picture below.
The broken off wire is black that leads to a yellow wire with a red stripe (Start Switch to Start Solenoid to Neutral Start Switch, maybe? found online I do not know what that means), which leads to an orange wire which connects to the "switch box assembly" then goes somewhere I cannot track it to.My question is what does this part do? It is called a switch assembly, but switch for what? The engine functions flawlessly as far as I can tell so I am at a loss haha.
It is part number 26 on the diagram below.
Thanks for any help!
In forward gear the motor is unlatched and will flip up when hitting something submerged, causing the switch to close and ground the ignition system momentary, shutting down the engine.
I tried soldering a new wire to see if i can save the switch, but after soldering new wires on, the old wires just broke. Digging deeper into the engine I found 2 other yellow wires coming off the stator that were pretty much just dust. I think they are the charging wires? I am not sure i will just sell it for cheap and show what should be done to the engine and let the new owner decide.