4000ft Above Sea Level Carb Settings 4.3 Merc

[Nmelche]

I occasionally pull my 1987 Searay Sorrento 19ft boat to my in-laws mountain house that is roughly 4,000ft above sea-level. My Searay has a 4.3 Merc engine with the 4 barrel rochester quadrojet carb. I have an extra carb that I would like to setup just for this altitude. Anyone have any suggestions as to what jet size I should use for that altitude? Took the boat up there last weekend and it was running very rich and was having trouble hot starting. Thanks!

 

[techmitch]

I occasionally pull my 1987 Searay Sorrento 19ft boat to my in-laws mountain house that is roughly 4,000ft above sea-level. My Searay has a 4.3 Merc engine with the 4 barrel rochester quadrojet carb. I have an extra carb that I would like to setup just for this altitude. Anyone have any suggestions as to what jet size I should use for that altitude? Took the boat up there last weekend and it was running very rich and was having trouble hot starting. Thanks!

I don't have any suggestions for you as far as the carb is concerned but I do know that even after carb. modifications, drive ratio has an extreme effect on performance at elevated sea levels.