Watch and listen: help me diagnose this problem please

Thanks ahead of time! Couple of short video clips to watch/listen to if you can. Motor is "warm" and warm-up throttle is all the way down. Choke is off.

So, I have:

- Link & synced (3 times to make sure)
- Turned out the carb idle screws about 1.25 turns or so (I've tried 1.5 and the result is basically the same)
- Checked compression, and it's perfect
- Made sure every plug wire is getting consistent spark and tested every spark plug

But it still runs at high idle and pretty rough as you can see. If I put her in gear (which I really shouldn't do at 1200 RPMs) she still hesitates and dies. What do I adjust next?



Thank you!

Did you check and make sure your not getting water in 2 of your cylinders. Make sure you have no cracked wires , What ever you do don,t give up.

i1bowhunter said:

Did you check and make sure your not getting water in 2 of your cylinders. Make sure you have no cracked wires , What ever you do don,t give up.

Click to expand...

Thank you so much for your response. As far as I can tell I have no water entering any cylinders. How do I check that to make sure? The whole powerhead is rebuilt with meticulous attention toward old gaskets being cleaned off and new put on to spec. Wires are gone over with replacements done. I'm exasperated. Yet, I know there is SOMETHING I'm missing....

Check plugs for water. Water droplets or chocolate milk looking. Like said you might just be missing something stupid,if any of the wiring is old I would look it them closely,Good Luck

FORGOT TO MENTION: This is a 1974 Merc 500 50hp.