It's an old Renault 4-cylinder carburetor engine in a boat. I don't know much about engines so let me know if I'm not including important information.
The boat is old but new to me. I drove it for about 4 hours, but now it won't start.
When I press the ignition switch, it turns ("reverevrev" sound)., but the engine never starts.
- There is gas and yes I'm pumping it into the carb and yes I've verified that it's getting into the carb.
- It started failing to to start immediately after being run for 4hrs and then turned off. I checked the battery and it's about 12.6V (but gradually falling as I keep trying to start the damn thing).
- If I'm persistent and keep pressing the ignition, the engine stops turning when I press the ignition, and I just hear the starter motor going "whiiiir". If I leave it for a while and then try again, it turns again, so I assume something has to cool down.
- When the ignition's turned on (but starter is not being pressed), the coil (leading to the spark plugs) gets hot. I'm measuring ~11.2V on the coil when the ignition's on, and 12.2V on the battery. There's also about 0.6V across the wire connecting the coil's negative terminal to ground, which I guess means there's a lot of current flowing across that wire, which would explain the heat.
- I took out the spark plugs, they were really black, so I cleaned the contacts with sandpaper and put them back in. (One of them seemed to not be insulated perfectly - 20MOhm resistance over the gap - but I'm guessing this is not the source of my troubles). Anyhow, this didn't seem to affect anything, and it still fails just as much as before.
So I suspect that there's something off with the coil, but I don't know what to normally expect here.
Any help is appreciated, by me and all people who buy crappy boats in the future.