Alright, this is a very interesting topic to me. As my 350 MerC needs a carb (leaky Q Jet), I have been delving into this topic and received many mixed signals. Some say don't dare put an auto carb in a boat, some say it's the same thing just richen it up. I understand boats are under vastly different loads than cars. It would be like a car going up hill all the time.
I have a good 650 Holley spreadbore (4175 Q Jet replacement carb.). I emailed Holley Tech, asked for a carb recommendation, and asked if I could convert my 4175 for marine usage. He basically said boats need to be much richer, you can replace the jets, pump cam, power valve, etc... but it still will not be the same b/c the channels and metering plates are different. His recommendation was a 4175 "marine" carb. Which looks identical to my 4175 but has the J tubes, and a huge price tag. Even the specs for the squiter, pump cam, jets were the same.
Anyway, my boat is small, only 19.5', fairly light, and has a shallow V-hull. It's not a cruiser struggling to get on plane. It really seems to me like I could put my 4175 "auto" carb in the boat, richen it up as needed, make some J tubes for the float overflows... is that reasonable?
I have a good 650 Holley spreadbore (4175 Q Jet replacement carb.). I emailed Holley Tech, asked for a carb recommendation, and asked if I could convert my 4175 for marine usage. He basically said boats need to be much richer, you can replace the jets, pump cam, power valve, etc... but it still will not be the same b/c the channels and metering plates are different. His recommendation was a 4175 "marine" carb. Which looks identical to my 4175 but has the J tubes, and a huge price tag. Even the specs for the squiter, pump cam, jets were the same.
Anyway, my boat is small, only 19.5', fairly light, and has a shallow V-hull. It's not a cruiser struggling to get on plane. It really seems to me like I could put my 4175 "auto" carb in the boat, richen it up as needed, make some J tubes for the float overflows... is that reasonable?