4.3L carb option

[toddbrown]

Hello!<br /><br />I have the merc 4.3L 6 with teh 2 brl carb. Would it be cost effective to buy a 4 brl carb to give better towing performance?

 

[rbezdon]

Re: 4.3L carb option

You need to replace the carb and intake minifold. Will cost quite e few bucks. It will make some difference but not a night and day change. If your towing most of the time you might consider a different prop for the towing. Just keep the WOT rpms under the max recommended. Then have a different prop for "running". The interchangeable type (hub mounted like the Michigan Vortex) are pretty eay to swap. A prop would be LOTS cheaper.<br /><br />In addition, I am not sure what the CFM rating on the 2bbl you have but if you read on sizing carbs for engines I think you'll find that the 4.3 can only process so many CFM of air and the 2bbl you have may already be fairly close to the max. See a couple of the other posts on carb sizing .

 

[toddbrown]

Re: 4.3L carb option

Ok, I am already using the Pro Pulse adjustable prop with 4 blades. It is a GREAT prop and I love it. I just would like more power but I think the only real cost effective was is to buy a new boat with a 5.7L fuel injected engine. IS there much difference between the carbed 4.3 and EFI 4.3? I knwo there is 30Hp but is that noticeable?

 

[bluewater19]

Re: 4.3L carb option

Todd,<br />Go on ebay and buy a 4.3L cast iron 4bbl manifold like this one.<br /><br /> http://cgi.ebay.com/ebaymotors/4-3L...567454247QQcategoryZ50442QQrdZ1QQcmdZViewItem <br /><br /> Then get your self a 600cfm edelbrock marine carb from summit racing Ask them about the strip kit for a marine 4.3 with the right jets ect. edelbrock makes this kit just for marine 4.3s. Edelbrock also makes an aluminum intake for your 4.3 vortec if you want even more ponies but it costs about 100 more than the cast iron intake.<br />Slap those babies on your boat and let the good times roll.<br />Don't listen to the people who say it's not worth the cost ect.... 400-500 bucks is pretty cheap for what you get.<br />I have done this swap so I have seen first hand what this swap does.<br />Better holeshot, faster top end and better fuel ecomomy at part throttle cruise.<br />Talk to bondo about his 4.3 with around 225 hp and ask him what he thinks of these swaps. He is the one who got me to do mine and had nothing but nice things to say about the swap.<br /><br /> If you just like to spend money Go buy a new boat with the 300 mag!!<br />good luck!