what size carb for mercruiser 350 magnum
 

I've got a mercruiser 350 magnum with the quadrajet carb on it. It's been giving me some issues I'm thinking of getting an edlebrock carb instead of just rebuilding this one. Somebody told me that the qjet on there right now is a 650 cfm and when i'm looking at edlebrocks all i see is a 600 and 750. What size should I be looking at for a replacement? the boat is a 20ft donzi minx

I have an edelbrock 1409 that is perfect I would sell ya. It came off my 350. I have the spread bore to square bore adapter plate too.

All Q-jets are rated for 750 cfm, with the exception of a few 800 cfm models that were installed on early 70's Pontiacs and Buicks.

What kind of issues are you having with the Q-jet? My experience with them is that once they are set up, they are pretty much rock solid reliable, especially on a stock engine. Could it just need a basic rebuild? Wouldn't be surprised if you had some bad gas go through it. Also, if it is on an older boat and the carb has not been rebuilt recently, it could be an issue with ethanol in today's gas attacking the needle and seat and other parts. The newer Q-jet rebuild kits have a neoprene needle and seat to deal with this issue.

I have no issue with a good quadrabog (kidding), but I will say the 1409 600cfm edelbrock will bolt on and be perfect for your application. You should run the adapter plate and will need electric choke wire ( or just wire the choke open, not needed for the most part anyway unless its real cold).

leave it alone..you wont notice a performance differance..

THIS!!! Agree completely. Figure out the issue with your Q-jet, fix it, put the hatch down, and enjoy the summer.

Send your carb to the Carburetor Shop in Ontario California. They have done several carbs for me and do excellent work.
Your carb will be returned better than new.