mercury marine sold a ton of marine engines with quadrajet 4 bbl carbs.these carbs are designated as marine carbs.do they have j tubes or sealed throttle shafts?

No, but they are black...

that really helps!

I can't remember if it was Quickfuel or Holley posted some literature the the black anodizing on the carb actually showed a small increase in power. I know it's kinda off track to the discussion but I thought it was an interesting piece of information.

I tried all sorts of coatings, including teflon based, and etc, etc and I found no power with throttle bodies.

HArd anodizing in carbs, though, make perfect sense ! Anything to keep electrolysis and other schit out of carbs is well worth it.

That's why there is NO Polished Aluminum on these new motors! I even Black Anodized the alum timing covers!

You can get the fast dual channel wideband with 22ft, 12ft, or 6ft cable

that reminds me of a guy who told me his engine ran seven degrees cooler after he painted it black.it never ceases to amaze me some of the bs guy,s come up with.

Quickfuel claims 6 degree drop in fuel temperature with black diamond coating.

I can make any carb run twice as cool or more...for free. Drive around heat soaking the engine and the put the fking hammer down for 5-10 minutes or more. LOL.

All that fuel flow and air flow will drop it right down.

On a more serious note, can't dispute what QF says unless tested, bu he 6*F is no big deal. Big deal to me would be extra protection to possible junk and electroysis happening inside carb while sitting for a bit.