did this have an answer ?

No sorry,
I was able to check at 1000 rpms and got 10-11 degrees so I figured seeing that timing wasnt an issue.

If timing is good, I'd go ahead and kit it! Also check the floats to see if they are leaking(brass) or saturated (composite) and make sure the check balls are present and loose under the accelerator pump and squirter nozzle. I have taken apart 'rebuilt' carbs that these check balls were missing or stuck. Nothing too complicated makes a Holley flood

Floats are brand new on this carb and it does not have the check balls under the accelerator pump, it has the silicone check valves and those are also new.

Did it ever run right or did you buy it and find out this was the case? Do you have someone else that has a carb to borrow? Doesn't have to be the 'right' carb for the engine, just something that fits and works. Sounds like you've hit all the obvious stuff on this carb. If a different carb works, great, we know are on the right track. If a totally different carb does basically the same thing, then we need to get to the 'not-so-obvious' level. Distributor issue, cam timing off, slipped balancer (moves the timing marks). Wish I was there to help, I'm much smarter sitting over the engine drinking a beer!

I have another Holley that is working perfectly fine on a SBC I can try but at the time I didnt want to go through the effort of taking it out of the other boat and putting it on this one, I now wish I did this way earlier. Im 99% sure its a carb issue because the motor is pretty clearly getting flooded.

Unfortunately though up here in Michigan we had a 25 degree night earlier this week and I made the call to winterize the boat that night. Im going to take the carb off 1 more time and go through it to see if I can find anything but this motor will not be started back up again until spring time.

Great question.

Answer ?

I was told it ran fine before the carb was rebuilt earlier this summer. Supposedly whoever rebuilt the carb screwed it up.

97 posts and we have our answer......

Sorry, this information was purely a starting point for me and that's all I wanted to use it as. I have no proof or information on what work was done before I got my hands on it other than I was told what I stated above. I have learned over the years to not trust what people "tell" you so I want to make sure all my bases are covered.