I have a chevy 350 with a jacuzzi jet pump. The carb came off a car (I am told) and I would like to replace it with something a little more user friendly since it doesnt have any manual adustments, just metering rods. If I go Holley, should I put a 650 ot 750 (spread bore)  or what else out there is user friendly?

Thanks

It was actuallt GT Jets that posted this to me.....".Someone just threw an automotive motor in your boat......."

If its a non feedback q-jet, I'd keep it.  They go for 100K miles in a car without looking at 'em....and perform damn well if they haven't been screwed up by someone.  If you've got a stock 350, there isn't a carb out there that will run any better without plenty more changes being made

I love me a good Quadrajet on a small block...

It was actuallt GT Jets that posted this to me.....".Someone just threw an automotive motor in your boat......."

I did..... And the problems that I remember that you face are that you have an OEM iron EGR intake manifold, improper linkage attachments and an automotive HEI.

If you want to do something on the cheap, I still stand by rebuilding the Q-Jet.

These carburetors are an engineering marvel...

As far as user friendly tune-ability... They have replaceable jets, metering rods, an adjustable secondary butterfly among some other tweaks that the average Joe can do....

If you want the best performance you can get... Get an Edelbrock RPM Air Gap and a square bore 650-700 CFM Holley or Holley clone (Quickfuel has some nice stuff), but be prepared to drop some coin.

I have built some mean small blocks and the secret is in the camshaft and the compression ratio, you more than likely have neither.

What are you trying to adjust? Literally everything on that carburetor is adjustable.

Float level, idle mixture, secondary pull in point, secondary fuel metering, primary fuel metering, accelerator pump stroke...Everything..

Lemme know what it is or is not doing and we'll see if we can figure it out...

GT

I have a backfire issue the exact same as "Santee_Native."  I've been told the motor is leaning out at WO, but my plugs arent white. GTJets...you mentioned something about my intake manifold, should I replace it?  What should I replace it with if I keep the quadrajet?

The carb has hoses on it that are plugged with bolts or screws. Maybe I will shop around for a marine version and chase from there. I nothing else...a piece of mind that the carb is OK
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As far as I know, the motor is as old as the boat..1976. I was think about replacing the valve springs which "cured" Santee_Natives problem.

I had a similar thing with my old boats BBC, not to that extreme as to backfire though. The boat would balls out to 5100 rpm forever if you flat footed it and held it. If you lifted at all, then flat foot it again, it fell flat on is face and spit and sputtered trying to get above 3500. Did the same thing if you just rolled gently into it. Weirdest thing I ever had to mess with. Spark plugs were perfect.

Immediately thought, Carb, or vacuum leak (Did find a couple small ones on the carb base gaskets and the same thing you described with "bolts and screws" plugging vaccum ports. This was a Holley 750, BTW. Replaced the base gaskets, put real caps on the unused vacum ports, 3 different carbs (2-750's and 1 850, all known good).

Still did it.

Also had the HEI on it. Replaced the cap, rotor, coil, plug wires and also noticed a lot of oil under the rotor, in the reluctor area, so cleaned that up and replaced the module in there also.

Still did it.

When I pulled the dizzy back apart, still in the engine, to check and see if I messed something up installing, was oil everywhere in there again (I had always noticed some oil gathering around the base of the dizzy and running down the back of the engine, but figured it was a bad O-Ring on the body of the dizzy to the block and I'd get to that someday. Didn't leak enough to really worry about)

A-HA!! Pulled the dizzy and the bushings inside were so shot that I think if I yanked hard enough, I coulda pulled the shaft clear out the top with the gear still attached!

I replaced it with a Unilite and Hyfire 6AL box,

Problem gone!!     HEI's are just not my gig, so fixing that thing up AGAIN (was $115 into it already) wasn't even on the menu.

Just one thought. Another simple one COULD, just maybe be, some on the site have seen this one also, that the rockers are wayyy overtightened and cranked down from someone trying to get rid of a lifter "tick" that was really a collapsing/failed lifter issue and not a simple adjustment issue. This would give every indication of a bad valve spring or two.

Ray   

Thanks guys, I looks like I have my work cut out for me..  Ray, we did tighten the rockers to try to get rid of a noise top left (helped a little), didn't overtighten though, had some loose ones. I think I will still do the springs and go down the list.

We call this "the smoking gun"...How were they adjusted?

The rocker nuts were adjusted by exact directions from a Chevrolet repair book specifically for the 350. If the engine is original, those springs gotta be tired after 36 years. No?

The engine was off and cold.