What Carb on my 5.7L Mercruiser

[garywwelch]

OK Experts,

The ? is: What replacement carb do you recommend?

I have a 93 Sea Ray 250 Express Crusier with the Mercruiser 5.7L engine. The boat is in a restoration stage. I have work to do to the outdrive but I will save that for next season (or post).

In order to run it this season, I will have to replace the carb. I am looking your suggestions and why you feel so strongly about your choice of carbs.
Thank you
Gary

 

[Mkos1980]

Re: What Carb on my 5.7L Mercruiser

What do you have now?

 

[garywwelch]

Re: What Carb on my 5.7L Mercruiser

It came with a 4 barrel. I plan to go back up with a 4 barrel. I have looked at the Edlebrock, Holly and stock.

 

[J. Mark]

Re: What Carb on my 5.7L Mercruiser

Well the carb on it is either a Rochester Quadrajet or a Weber (which is just a carter AFB, which is now produced by Edelbrock)

If you have the Quadrajet and want to go to the Edelbrock 1409, you will need to either change your intake manifold or use an adapter plate. Also you will need to either find or fabricate a fuel line as the old one will neither fit nor reach without lots of bending and it will almost cerainly kink before you can make it work.

I don't like quadrajets as much as the Carter AFB/Weber/Edelbrock design BUT
a properly set up Rochester Quadrajet will perform every bit as well and is a lot less trouble to put on an intake designed for one. Find a good (old timer) rebuilder if yours needs rebuilding and DO NOT GIVE IT GAS ON THE FIRST STARTING AFTER THE REBUILD or you will ruin the accelerator pump.

Good luck and if you locate the fuel line to convert the Q-jet set up to the Edelbrock post it here as I have not yet found it.

 

[180shabah]

Re: What Carb on my 5.7L Mercruiser

I like the weber/carter/edelbrock units, there is no external fuel bowl to leak and they are very simple to tune.

 

[meesh]

Re: What Carb on my 5.7L Mercruiser

The Edelbrock 1409 runs awesome right out of the box.

 

[garywwelch]

Re: What Carb on my 5.7L Mercruiser

Thanks for all the replies. I am one of the pain in the back side Newbies, but I really want to do this project correct.

On the carb - I should get a Marine application - correct? I had someone tell me it didn't matter, but it seems there is a reason they created the marine application. Thoughts?

Last question - any suggestions from these who have made the purchase - where can I get the best price on a new or manufactured carb. The one that came off is so badly corroded it is not rebuild-able.
Thanks

 

[wca_tim]

Re: What Carb on my 5.7L Mercruiser

Edelbrock 1409, marine carb, should be jetted correctly for your set up and work great right out of the box.

 

[haulnazz15]

Re: What Carb on my 5.7L Mercruiser

The marine carburetors are made with J-tubes and some other items that keep fuel vapors from escaping into the bilge and making your boat explode. Do not put an automotive carb on it.

 

[Fishermark]

Re: What Carb on my 5.7L Mercruiser

Last question - any suggestions from these who have made the purchase - where can I get the best price on a new or manufactured carb.

I too like the Edlebrock series of carbs - the 1409 would be a good choice for you. You can get good prices at either Summitracing or Jegs

 

[garywwelch]

Re: What Carb on my 5.7L Mercruiser

Again, thanks for the info. You guys have been very helpful. If I go with the Edelbrock 1409 will I need a specail plate or adapter for the existing intake or do you recommed going with the matching Edelbrock intake?

 

[180shabah]

Re: What Carb on my 5.7L Mercruiser

The performer manifold would be the best choice (if there will be no salt water in it) but the 1409 has a dual bolt patern, so it will bolt to either spread-bore or a square-bore manifold.

 

[Fishermark]

Re: What Carb on my 5.7L Mercruiser

Again, thanks for the info. You guys have been very helpful. If I go with the Edelbrock 1409 will I need a specail plate or adapter for the existing intake or do you recommed going with the matching Edelbrock intake?

You haven't said what carb you have on there now. You mentioned it was a four barrel... but there are spread bore and square bore four barrels. The Edlebrock is a square bore while the Quadrajet is a spread bore. You MIGHT have enough margin to mount a square bore carb on a spread bore manifold without an adapter... or not. It varies with manifolds. But if your current carb is a square bore, then you are certainly good to go with no adapter.

 

[garywwelch]

Re: What Carb on my 5.7L Mercruiser

As it turns out the intake on the 5.7L has lots of rust and pitting from it sitting up so long in Florida.

I am going with a performer set up from JEGS. Complete with intake and 600 cfm. Looks like I have my work cut out for me, but I want to do it RIGHT - ONCE.

I have been thinking about haveing the intake powercoated clear. It looks great, did it on a 66 Mustang project. Any one done this on a marine application?

Thanks for your input.
Gary