Quote Originally Posted by rspears View Post
I went back and re-read your initial post on this thread. As I understand, you bought a used, complete 454 from a 'reputable marine dealer'. If he is indeed reputable, we would have to assume that he knew some history of that engine, and that he had heard it run, if not even run it in the PO's boat before it was pulled. Bottom line, it would be reasonable to assume that it ran fine when he sold it to you.
Dealer installed motor and serviced before PO decided to upgrade to 502. As I said I, assumed the same.

Quote Originally Posted by rspears View Post
You then decided to "upgrade" to a larger, but rebuilt 850cfm carb to replace the 650 that it had. Since then you've had problems with hard starts and rough idle.
It had these problems from the get-go. The dealer advised me to move up to the 850. He says they run nothing less on their marine 454's. I assumed the new carb would fix the hard starting problem. Seems logical considering I have good FP and still have to mat the throttle to start.

I think your on point in regards to the gremlins. I'm still thinking though, with that much difference in cylinder compression. A leakdown test almost has to be first in line. Right?