Fuel tank size and usage

[Nater Potater]

Hey thanks for the links and info. Now, I've heard that Edelbrock carbs are way more difficult to work on that Holley carbs. Any truth to that?

Arguably, but what I've found in the past with both Edelbrock and the Q'Jets is that, once set, they're good to go. Holleys, at least in my experience, tend to be more of a maintenance pig that the other two. Leaks, in particular. Who in hell designs something that carries fuel to have vertical parting lines in the float bowls?

I also want to ask, besides the adapter and the carb itself, what else will I need to get to make this all work? Or is this mostly going to be a plug and play type situation. Specifically, do I need a regulator of some kind? Different jets? different spark arrestor (currently have an aftermarket K&N arrestor).

I can't offer any insight as to what additional pieces would be needed for the conversion. That might be one good argument for sticking with the Q'Jets. As for a fuel regulator, since they're both conventional float-bowl carbs, you should be good to go with the stock fuel delivery system if converting to Edelbrock or Holley. Jetting should be pretty close right out of the box, assuming you're purchasing a marine carb for your engine/outdrive combo. The only time you might need a change is if you run at "abnormally" high altitudes, or swapped to a more aggressive cam.

By the way, your boat looks amazing!

Jeez, no need to inflate his ego any more than it already is!

 

[Nater Potater]

I was working on the Holley in my '69 Dodge Superbee when my neighbor ambled over to see what all the commotion was about. When I pointed out the problems I was having, he asks

"Do you know what's worse than a Holley carburetor?"

"Having two of them!"

 

[Skybolt]

Concerning the spark arrestor - the key is to have a wire mesh. Newer Mercs do have a K&N style filter material used in there arrestors (I have no idea who actually makes it), but they also have the screen mesh. ...

And also USCG approved. Not just a wire mesh filter. Don't want the OP to think only wire mesh is ok.

 

[J-Rides]

Arguably, but what I've found in the past with both Edelbrock and the Q'Jets is that, once set, they're good to go. Holleys, at least in my experience, tend to be more of a maintenance pig that the other two. Leaks, in particular. Who in hell designs something that carries fuel to have vertical parting lines in the float bowls?

I actually got the same info from my brother who is an auto mechanic. I always try to use resources well - check with multiple sources and it's nice when they say the same thing. Set 'em and forget 'em is how he said it. But yeah, I don't know why Qjet had that design in their carbs.

I can't offer any insight as to what additional pieces would be needed for the conversion. That might be one good argument for sticking with the Q'Jets. As for a fuel regulator, since they're both conventional float-bowl carbs, you should be good to go with the stock fuel delivery system if converting to Edelbrock or Holley. Jetting should be pretty close right out of the box, assuming you're purchasing a marine carb for your engine/outdrive combo. The only time you might need a change is if you run at "abnormally" high altitudes, or swapped to a more aggressive cam.

Jeez, no need to inflate his ego any more than it already is!

Thanks - looks and sounds like I shouldn't need too much else if I make the switch!

 

[Lazy Daze]

And also USCG approved. Not just a wire mesh filter. Don't want the OP to think only wire mesh is ok.

Absoluteley. Good clarification.

 

[Flyer5]

Arguably, but what I've found in the past with both Edelbrock and the Q'Jets is that, once set, they're good to go. Holleys, at least in my experience, tend to be more of a maintenance pig that the other two. Leaks, in particular. Who in hell designs something that carries fuel to have vertical parting lines in the float bowls?

I can't offer any insight as to what additional pieces would be needed for the conversion. That might be one good argument for sticking with the Q'Jets. As for a fuel regulator, since they're both conventional float-bowl carbs, you should be good to go with the stock fuel delivery system if converting to Edelbrock or Holley. Jetting should be pretty close right out of the box, assuming you're purchasing a marine carb for your engine/outdrive combo. The only time you might need a change is if you run at "abnormally" high altitudes, or swapped to a more aggressive cam.

Jeez, no need to inflate his ego any more than it already is!

I always thought the Q-jet was the closest thing to Fuel Injection out there in the carb world. Also very easy to repair / rebuild.

 

[Nater Potater]

I always thought the Q-jet was the closest thing to Fuel Injection out there in the carb world. Also very easy to repair / rebuild.

I'm not sure I'd go that far, but the Q'Jet has one big advantage in the automotive world; being as it's a spread-bore design, the primary's small diameter means that the air velocity remains quite high, even at lower engine RPMs. With that, you stand a better chance of more thoroughly atomizing the fuel, giving better control over the air/fuel ratio (better economy). Unfortunately, on a boat, unless you do a lot of cocktail-speed cruising, you're getting into the secondaries. At that point, you actually get a more even distribution across all cylinders with a square-bore like the Edelbrock or (dare I say) Holley. A lot can be done to negate that with proper manifold design, just like you see on the stock engine setup. That's also why I suggest not running a square-to-spread-bore adapter, as you alter the distribution. The only "good" way around that is to swap the entire intake manifold for one that's designed with a square-bore in mind.

 

[J-Rides]

Quick follow up on this thread... I did replace both stock quadrajets with the Edelbrock 1410 750cfm carb on my 1986 Sea Ray 340 Sundancer with the Mercury 5.7L 260 engines. We took one trip with it at the end of the year and saw a noticeable difference in power and no drop off in fuel economy - don't have the exact numbers.

Anyways, wanted to say thank you to those who helped me in the process. Looking forward to next year!