1976 mercury 650 problems

[ShoestringMariner]

Hey all, I ran my new to me 1976 Merc 650 tonight for about four hours. I took it out fishing. Did a fair bit of trolling. Did not seem to like the idle very low for long periods of time. Had to use the idle lever to keep the revs up just a wee bit. Anyway, concerning part was when I was wrapping up;
I just stowed everything away and went to give it a hole shot. It responded and started to climb on plane and then died suddenly. I thought it was out of gas. I checked the fuel and it was still good. Primer bulb still had gas in it. It was very hard to start again. Wide-open throttle, extended cranking, chug chug starting. Took what seems like forever to clear and run properly again. Then it lit up and I made a good full-tilt run back to the launch.

During the difficult starting, I thought I saw a bit of vapour escape from the cover plate.

Could this have been vapour lock?

there are other known issues with this motor BTW. The wiring is split and rotten in some places. I haven’t gone through and replaced anything yet. It seemed to run fine until tonight.

 

[Chris1956]

You will need to repair/replace the wiring, before it destroys your expensive ign system. As for the performance issues, I would suspect the carbs are a bit dirty, and the motor may be out of link and synch specs. It is probably best to check it.

Carbs need to be set precisely to get a decent idle and still accelerate.