1978 Mercury 402
Cadet
- Joined
- Oct 23, 2017
- Messages
- 7
Hello all,
Engine will only crank 1/2 revolution and will not crank fast enough to start with each start attempt. I have seen similar threads on this issue however never seen the issue resolved. Now for the details:
Old (1978) motor that my father in law owned. Parked outdoors for 20+years and never ran. Best of my knowledge it was winterized and it ran fine when parked.
I have installed new exterior wiring harness, new starter, new plugs and plug wires (I do have good spark from both plugs), new fuel tank with new fuel 50:1. Fresh oil in lower unit with new impeller.
Engine rotates freely with spark plugs out and starter engages properly etc. When I install plugs there seems to be so much compression that the starter cannot rotate the motor fast enough to get a start. Yesterday I tried wiring 3 batteries in parallel in order to maintain power throughout the start. This was also unsuccessful.
I was going to try and replace the heavy gauge wires going to the starter next, however, I don't believe this will help either. The core problem is that then engine is very difficult to rotate when the plugs are installed?
Any help would be greatly appreciated!!
Thank you,
Chad
Engine will only crank 1/2 revolution and will not crank fast enough to start with each start attempt. I have seen similar threads on this issue however never seen the issue resolved. Now for the details:
Old (1978) motor that my father in law owned. Parked outdoors for 20+years and never ran. Best of my knowledge it was winterized and it ran fine when parked.
I have installed new exterior wiring harness, new starter, new plugs and plug wires (I do have good spark from both plugs), new fuel tank with new fuel 50:1. Fresh oil in lower unit with new impeller.
Engine rotates freely with spark plugs out and starter engages properly etc. When I install plugs there seems to be so much compression that the starter cannot rotate the motor fast enough to get a start. Yesterday I tried wiring 3 batteries in parallel in order to maintain power throughout the start. This was also unsuccessful.
I was going to try and replace the heavy gauge wires going to the starter next, however, I don't believe this will help either. The core problem is that then engine is very difficult to rotate when the plugs are installed?
Any help would be greatly appreciated!!
Thank you,
Chad