Gibbles
Commander
- Joined
- Nov 14, 2009
- Messages
- 2,027
Short story:
My 1975 Mercury 650 65hp 3 cyl will not run when the battery is disconnected
Does this engine use the battery as part of the circuit, or do I have a charging issue?
Long story:
I picked this engine up very cheap and not running, the guy I bought it from told me the dist cap had a weak spring on the carbon contact causing issues.
I found out this was true as someone installed the spring backwards, but this was not the main issue.
I went through the engine, rebuilt carbs, and new water pump, and the engine fired right up, it ran for a few seconds and then shut off.
It had a weak/intermitent spark...
After some TS I found out that the wiring harness plug had very high resistance and I had to cut it out and hard wire it, after that the engine starts up and runs great.
I had the engine connected to my battery via jumper cables and I knocked off the negative cable and the engine shut off.
From what I have seen with other outboards is they do not need the battery to run/start
My FIL's evenrude 85hp for example, we can disconnect the battery, and wrap a rope around the flywheel and it will fire right up.
The mercury 65hp will not, is this by design or do I need to start trouble shooting the charging system?
Note that right now I only have the basics connected to the ign switch (four wires), two to put the engine into run mode, one for choke, and the 4th for the starter solenoid
Thanks in advance for any assistance.
My 1975 Mercury 650 65hp 3 cyl will not run when the battery is disconnected
Does this engine use the battery as part of the circuit, or do I have a charging issue?
Long story:
I picked this engine up very cheap and not running, the guy I bought it from told me the dist cap had a weak spring on the carbon contact causing issues.
I found out this was true as someone installed the spring backwards, but this was not the main issue.
I went through the engine, rebuilt carbs, and new water pump, and the engine fired right up, it ran for a few seconds and then shut off.
It had a weak/intermitent spark...
After some TS I found out that the wiring harness plug had very high resistance and I had to cut it out and hard wire it, after that the engine starts up and runs great.
I had the engine connected to my battery via jumper cables and I knocked off the negative cable and the engine shut off.
From what I have seen with other outboards is they do not need the battery to run/start
My FIL's evenrude 85hp for example, we can disconnect the battery, and wrap a rope around the flywheel and it will fire right up.
The mercury 65hp will not, is this by design or do I need to start trouble shooting the charging system?
Note that right now I only have the basics connected to the ign switch (four wires), two to put the engine into run mode, one for choke, and the 4th for the starter solenoid
Thanks in advance for any assistance.