Printable View
Guys....looking for some $.02......
My 1976 454 Marine Power engines in my boat need to have the carbs "fixed". The floats have been sticking and it's gotten a bit hard starting. Carb rebuilds are about $250 these days up here in NW OH.
So...got to thinking.......should I just rebuild or spend a $100 or so more each and REPLACE:confused: them with some new Holley's or other brand. They are the original carbs!
Thanks for any insight you can send my way......
Todd
I used have each carb rebuilt every other year. then I got smart and got a neww edelbrock marine carb - didnt had to rebuilt since purchase.
Rebuilt is a big variable. some shops machine the core and re manufacture it. others replace soft parts only. New edelbrocks sound like a good idea.
Are they Quadrajet carbs? QJs can be very troublesome and had several known problems, including floats that wouldn't float, casting plugs that didn't plug, and secondary air valves that seemed to be delivered new out of adjustment. When you add that to ham-handed 'tuners" who make adjustments or substitute parts to make "more power" (and which usually has the opposite result) you can end up with something that isn't going to work very well unless it's gone through in some detail and by someone who is familiar with the QJ issues and is prepared to correct them. A rebuild kit is, in all likelihood, not going to do anything useful unless the other issues are dealt with first.
You CAN make a QJ work fine but bolting on a replacement Edelbrock would be less stressful. However, i would suggest that whatever replacement carb you decide to use, it should be bolt-on with no weird linkages to fabricate, no manifold machining, no trying to figure out how to get a choke to work, etc - just remove the old carb, bolt on the new carb and connect everything.
Good Luck
quadrajets run so nice though when they are done right. they are a great piece of engineering
edelbrock, no holley.
I believe edelbrock purchased rights to the Qjet then made several improvements, cant go wrong with Edelbrock.
Correct. And while at it, why not throw on a higher performance intake? They can make a pretty decent bump in power, with no real downside other than initial cost.Quote:
Originally Posted by 67hat34c
Unless you are going for more horsepower, I don't think a high rise manifold is going to give you very much, probably not enough to justify the cost of the new manifold. If you go with a new carb, give your supplier the specs on your engines, and get the correct size carbs. Oversizing a carb typically will burn more fuel with little increase in power. Newer always seems better, but a correctly rebuilt QJ works just fine.
This is meant in pure jest: Come on, man up and rebuilt 'em yourself.....even my wife can rebuild a q-jet unassisted (I was on the other side of the world).
I wouldn't go high rise for a boat like this...but with PERFORMER MANIFOLDS (power band is idle to 5500 rpm). Performer manifolds are dual-plane, low-rise intake manifolds with a 180° firing order and patented runner design that you won't find in other brands. This patented design greatly improves torque over a wide rpm range for excellent throttle response, especially off-idle through the mid-range. Performers are ideal for passenger cars, trucks, 4x4s, tow vehicles and RVs. There are EGR and non-EGR versions. (stolen from the Edelbrock site). I ran one of these on my Donzi Sweet 16 that had a v8 transplant. Loved it.Quote:
Originally Posted by Boatnut
I don't want to get much into this manifold thing; I would just suggest this...If it's a stock engine internally and you plan to leave it that way, leave the oem manifold in place; just bolt on the new/rebuilt carb and be done with it.
I went through this years ago. I took Qjets off two Merc 454s and put on Edelbrocks. They were great- ran well, used less fuel, and not a moments' trouble with them. these were the 750s, I think.
Here's a good price.
http://www.atlanticspeed.com/product...idCategory=136
If you are running a PCV system, you will have to drill and tap a fitting. Otherwise a simple upgrade. Don't buy more than a 600 CFM no matter what your friends tell you.
Eric
I agree that the carbs Edelbrock sells are very good and would add my recommendation re them.
OTOH, I note that their marketing folks are, like most, a bit "overenthusiastic." This from their description of the carb: "Designed and calibrated for optimum marine performance in small-block V8 engines with a variety of manifolds that include Edelbrock Performer, Performer RPM, RPM Air-Gap, Torker II and other brands of similar design."
All these manifolds send different signals to the carb - it is not possible to achieve "optimum" performance with the same carb/setup on the same engine using each of these different manifolds. I'd offer that a more accurate description would be "Designed and calibrated for easy installation and trouble-free marine performance..." Then again, their marketing guys are probably a lot better at selling carburetors than I would be! :)
But they are good carburetors!
And you get a free hat with each Edelbrock carb!! so you have two free hats.
Even the Hatteras Owners' Forum doesn't give free Hatts............
What more could anybody ask for! :)
Quote:
Originally Posted by jim rosenthal
Not true Sam's gave me a free hat at the boat show because I was a Sam's customer!
FWIW, I had troubles with the Carter AFBs on our new-to-us Chris Craft Commander 42 last year. I picked up rebuild kits from an online supplier for about $40 each. The whole rebuild process took about 3hrs, from lifting the hatches to closing them up again. There was both water and...goop...in both carbs. That was 20 running hours ago and they've been working really well ever since.
Unless there was something really horribly wrong with the originals, I'd just rebuild 'em myself.
Not as easy with the old quadrajets.
Yeah - the Qjet is probably the most complicated standard production US carb ever made AND it had production casting plug leaks that need to be addressed in a rebuild as well.
Find a copy of "Rochester Carburetors" by Doug Roe. It's a comprehensive book on what it takes to do the infamous slobberjet right. They actually are good carbs when you get past the few known issues. They've mixed fuel for millions of GM vehicles and even a Ford CobraJet. If Ford is buying a GM carb for one of their high performance engines it can't be too bad.
Which is why they are known as Quadrajunk and/or Quadrabog within many automotive circles.Quote:
Originally Posted by MikeP
Right.... and Ford Variable Venturis and Jezus Chrysler Thermoquads were far simpler and more reliable. :rolleyes:
Based on my experiences with them, with a fresh and GOOD rebuild, and proper tuning, they are fine for a couple of years...and actually work well...but not for long. That's when the Quadrabog rears it's head. The new/updated ones being sold today don't seem to have that problem. Thats coming from my days of owning 60s and 70s Impalas. YMMV
holt shit ----did you say variable venturi? what a piece of crap..... we had them on about 500 police cars in the eighties... thank god for fuel injection
I've owned my boat for 9 years with quadrajets and haven't had a bit of trouble.
haters gonna hate.