Anybody running a mech. secondary carb?

[ringmaster72]

I am having trouble with my vacum secondary holley. It does not kick in until 3000 rpm, no matter what spring I use. I would like the back barrels to come in sooner so I am thinking of switching to mech secondary.

 

[maxxman04]

Re: Anybody running a mech. secondary carb?

no sec. til 3k rpm's on any carb indicates possible vacuum leak, either around carb, around intake to head surface. might get a vacumm tester, see how much vacuum is being pulled thru manifold, thru carb. to answer tho, mech. sec. are run, no prob.

 

[mkast]

Re: Anybody running a mech. secondary carb?

What size carburetor on what size engine?
Ever wonder why mechanical secondaries aren't installed on marine engines?

 

[ringmaster72]

Re: Anybody running a mech. secondary carb?

Pretty sure its a 650 cfm. One post says mech secondaries are run adn the other says "wonder why they arent"? What is the deal?

 

[picklenjim]

Re: Anybody running a mech. secondary carb?

I've run one for 20 years and it works great. Holley and Demon make marine carbs with mechanical secondaries.Mercury had them on their high performance big blocks years ago.Now their all electronic fuel injection is the only reason you don't see them anymore.http://www.jegs.com/p/Barry-Grant/Demon-Mighty-Marine-Demon-Carburetors/755474/10002/-1

 

[ringmaster72]

Re: Anybody running a mech. secondary carb?

Oh yeah, it is a 355 chevy with 350-375 horse.