Re: 80’s/90’s 50hp opinions?

[Don]

Well, Casey’s technique for evaluating one of these engines is spot on for sure….But, we do need to be careful, just cuz it won’t idle does not mean it is wore out…Compression seems to be normal, but we realize this is not necessarily an guarantee all is well inside. Are you able to peek inside the cylinders with some sort of inspection light? Generally speaking, even an engine with plenty of wear will run OK below half throttle, it just fades away and dies at low speeds/dead idle. So, am I reading your post correctly? You mention that the engine dies out at any speed below half throttle but can be revived with the primer. You have done sync/link, did you check flywheel TDC position?
At this point, I would try to peek inside the plug holes to see if there is excessive scoring or aluminum transfer…If all seems "OK" inside, I would pull the carbs apart. Just kinda sounds like the low speed circuits are plugged up….
What did the customer report? Did the engine run OK last year, but refuses to idle this year? If so, I am more convinced there is a carb problem.
Again, I sure don’t want to condemn this powerhead because it won’t idle….Do you have carbs from a known good idling engine you could substitute?