Info On Possible Carb Upgrade Please

[johnebquick]

As money allows and circumstances dictates, I would like to do some modest upgrades that I can handle. The most recent upgrade I'm thinking of doing is replacing my old 1979 4 Bbl Rochester QuadraJet with somthing that will be more reliable.

Any suggestions on which 4 Bbl carb I should go with? Is an electric choke better then a vac/coil activated carb? Can it be crossed over? What would be the cost of a remanufactured carb over a new? Please give me input. I'm in the beginning stages of doing the research into this.

Thanks,
John

1979 SeaRay 24ft SRV
Merc 5.7/350ci Motor
Alpha 1 Gen 1 lower outdrive 50.1

[seapower]

What's not reliable about a Rochester Quadra jet? I used them on a commercial boat I used to own. It was used daily, for month's at a time, no issue's. I do work on gas boat's from time to time, I haven't had a "Rochester" problem. Maybe "Jaw's" will pop in and give you a hand. Frank

[johnebquick]

Remember, I'm not knowledgeable on this subject and I'm only speaking of reliability due to age, not defect. I just thought that with the little bit of reading I have done on this subject and now knowing that they aren't made anymore, I just thought there might be a better alternative then my 30 year old carb. I just wanted to see what was available and what the technology has given us in the past 30+ years. Due to its age and needing a good rebuild, what are my options? It's running now but it searches up and down at low RPMs. I know it would improve the overall performance of the boat to do a upgrade with a Re-maned, Refurbished, Rebuilt or new carb package.

John

[johnebquick]

Here is the Ser #

17059288 / 3548

170___________Produced after the year 1976
70 was prior to that

59____________Dictates the year of 1979

2_____________Emission code of 49 state legal Q-Jet

8_____________Non GM Division / Mercruiser

8_____________Date of the actual year produced (1978)


Date Code of 3548

354___________Julian day it was made in the calender year. 354 dictates December 21st.

8_____________actual year it was produced (1978)

This is an original Carb and IMO I think I would definitely benefit from an upgrade.

[Avenger]

With the exception of electronics, basic carburetor technology hasn't changed much in the last 75 years, and Q-jets are a pretty proven design. Hot-rodders have a dislike for them because they're production carbs and there's no performance parts available for them like there is for Holleys, but for a stock application they're hard to beat.

Usually "upgrades" just downgrade function and reliability. Because properly setting up a carb isn't a matter of just bolting it on. I can't tell you how many guys I've seen bolt on a fat double pumper thinking they'd get a big performance boost and end up with a bogging, fuel slobbering pig.

I would bet that yours has the common Q-jet malady of leaking plugs in the pickup wells which is screwing up the fuel metering at idle. It's easily fixed with a little epoxy. Find yourself a reputable carburetor rebuilder, or get the Rochester book from Motor publications and do it yourself. I'm not a "gas guy" either, but I've rebuilt a few of my own and they've worked fine.

If you're really that bent on a change I understand Edelbrock makes a pretty nice replacement for a Quadrajet. But if it were me I'd avoid all the re-engineering.

[34SILVERTON]

try an edelbrock marine with an electric choke. i put them on my chryslers and they work great.

[seapower]

Well said my man!!! No need in trying to re-invent the wheel Common sense prevail's. Frank

[Avenger]

Thank you Frank! I don't know if it's common sense or experience, but I've been bit and seen many people get bit by trying to outguess the engineers. Just like fishing, there's usually a lot more to it than what appears on the surface.

[johnebquick]

Thanks for the advice guys. That's what I wanted, some good honest advice. Like I said, it wasn't due to the performance reliability, It was the age of the unit. I just thought things might have changed. I like good honest opinions and real answers. Believe me, I'm not trying to re-invent the wheel, just wanted to know if there was a better alternative. Looks like I'm looking for a Rochester manual or a rebuild shop then. On my 21ft CC 120Hp Evinrude, I ending up buying 4 rebuild kits and taking all 4 carbs off. I rebuilt them on the shop bench and reinstalled them. WoW! what a difference in performance. I'm not talking about more HP but it just ran so much better.

Any suggestions for northern Delaware on rebuild shops? I'll look on the Net for some rebuild Manuel's to see what I can find.

Thanks,
John

[Avenger]

I find this book; "Rochester Carburetors" By Doug Roe to be an excellent resource:

http://www.amazon.com/Rochester-Carb...b_img_b#reader

Very practical, and demystifys a lot of Quadrajet folklore.

Sorry I can't help you with local rebuilders in your area. However, if you can rebuild your Evinrude carbs, with the book's help you should be able to do a Slobberjet too.

Good luck with your reman, and please let us know how you do.