carb for mercruiser 5.7

[strombolichef]

Hello, I am in mid rebuild on 83 Merc 5.7. The carb that came with the boat and is totally in need of repair is a quadrajet.
I have read a lot of bad stuff about them here, I am wondering if there is another simpler, or more reliable carb that I can put on there instead. What is the standard for that engine when originally built?
Thanks for the advice.

 

[JustJason]

Re: carb for mercruiser 5.7

There is nothing wrong with a Qjet except for the occassional bowl plugs seeping. Plug those up with some epoxy and its still one of the best carbs on the market today.

 

[cr2k]

Re: carb for mercruiser 5.7

Qjet is the OEM carb. a Holley is good but you need an adapter and a marine carb. It would be far cheaper to rebuild the quardajunk.

 

[jtybt]

Re: carb for mercruiser 5.7

Q-jets have been the OEM carb on more auto's and marine engines than any other. They have a couple idiosyncrasies just like all brands. The leaking well tube plug is well known. Loose secondary upper plate springs are another.

Holley had their power valve subject to blow-out from back-fire thru carb. If you know the problem, you can fix it.

 

[Alpheus]

Re: carb for mercruiser 5.7

Dont listen to THEY. Rebuild the Q-Jet. I just rebuilt one and the kit was 22 bucks. They have a bad rap because of ignorance. Rebuild it and use it...

 

[zbnutcase]

Re: carb for mercruiser 5.7

I agree with Alpheus-ignorance is the prob. They are great carbs, very adaptable-I made one work on a 1600 Datsun engine back in high school for the heck of it. 'nutcase

 

[Greg Gessler]

Re: carb for mercruiser 5.7

Get a good book on Quadrajet carbs and you can do it yourself.

http://www.gesslerheadporting.com/gesslerheadporting/ghp.nsf/822dcaaaa26c6da985256dd80023623d/61b7042c9369c91b8525751a00722f31!OpenDocument

 

[fossill]

Re: carb for mercruiser 5.7

I used to rebuild several carbs a day back in my auto days. The Q-Jet was by far the easiest to fix and the best carb out there INMHO. Some of the others were very particular to adjust and set up. The Holley I never did like, easy to overhaul but not very durable..ie; gasket leaks.

 

[jy118lfd]

Re: carb for mercruiser 5.7

Get the Cliff ruggels Book and then call him. His website is http://www.cliffshighperformance.com

Get his kit as the aftermarket kits leave a lot to be desired.
I have worked on many Qjets but I learned more from his book than 10 years of "rebuilding" carbs. They are so easy to work on and so reliable once you understand the circuts and what does what.

You will not be dissapointed with the carb after it works right. I have one on my 5.0 and it is as close to fuel injection as you can get.

 

[JustJason]

Re: carb for mercruiser 5.7

A carb set up properly can have a better throttle response than fuel injection.
Problem is, fuel systems get dirty, and people who don't know what they are doing touch carbs.
And then there's the whole temperatur and altitude thing

 

[Gary H NC]

Re: carb for mercruiser 5.7

Agree with all of the above.

I have had a few older hot rods over the years.One was a Camaro with a 350 in it.The original Q-Jet was in need of a rebuild so i figured why not just throw a new Eldelbrock on it.It ran like crap so i returned that and got a Holley.I never could get it right either.
I rebuilt the Q-Jet and it idled and ran perfect for years after.

In my opinion they are great carbs and when set up right will kick butt!
Nothing like the sound of those secondaries kicking in!

 

[dan t.]

Re: carb for mercruiser 5.7

what can I say that hasnt already been sayed here, stick with the q-jet, you will be happy you did

 

[kevincave]

Re: carb for mercruiser 5.7

qjets are really a simple carb to rebuild and cheap..

 

[strombolichef]

Re: carb for mercruiser 5.7

Thanks to all for the advice, It seems pretty clear to me what I need to do!!!

 

[Ohioriver]

Re: carb for mercruiser 5.7

I also an 83 Mercruiser 5.7 took the carb off the boat myself, and took it to a shop and they soaked it and rebuilt it and it was around $125. They know what there doing, I didn't. Runs perfect.