DonMan

Just bought a new Holley 800 cfm mechanical secondary carb (0-9022). I was informed that stock jetting is 72 primary / 87 secondary. Doesn`t this sound wrong?
I was just curious as to what I may be looking at to fine tune this to my stock 454 (Vortec heads, Edelbrock intake, SM exhaust). I`m running a Holley RED pump (no reg.) 3/8" line and a HP500 flame-arrestor.
I boat at 900 ft above sea-level with moderate humidity. I know this is a loaded question, but was wondering what set-up other guys were running.

blue thunder

I can't help you Don cause I am a Holley wannabee. I am still interested in what OSO tech has to say for when I can pony up the jingle.

BT

DonMan

I just ponied up a lot of jingle for this carb and the Air-Gap intake it`s sitting on. Not to mention the Holley pump to feed it and the flame arrestor to filter it. Then if you add in all the little crap like gaskets, throttle brackets, hoses, clamps, fuel line, bolts etc....It`s a lot of jingle.
Then I just had to have that water crossover and the purty thermostat housing to match. At the same time I opted for the purple-anodized aluminum battery boxes......
Now, my boat runs like crap and my wallet is much lighter. Welcome to boating.
I was just curious as to other guys jetting, thinking this may be the answer to my pitiful performance.
Oh, did I mention the Stainless Marine manifolds? Those were a chunk of change.
Guess I need to "Break Out Another Thousand" and maybe I can cure this with a dose of cash...

blue thunder

You're crackin me up Don. This perf boating is expensiiiive! I have twins so walk with me a while and feel my pain! This is why I am a wannabee holley guy. One thousand clams for new 800s with all the fixins! Ouch.

Come on fellas, let us know the reciepe for the 800s. We won't tell anyone

BT

MACDAD260

I just felt the pain myself. New Holley 800, Gaffrig flame arrester, linkage plate, stainless dual feed line and Aero-Quip braided line and fittings from fuel pump to carb. OUCH! It looks cool though. The motor is a Gen V 502 Magnum with an Edelbrock Performer RPM manifold.

So far, I have ran it on the water two times. When I first ran it on the hose it idled way too rich. I changed the 6.5 power valve to a 4.5 and now it idles fine. The first time out I started with 76 primarys and 89 secondaries. I was using the old plugs that were black from the rich idle problem. I made a few short speed runs and pulled the plugs. They looked pretty good but I thought maybe I was still too lean. The next time out I installed new AC CR43TS plugs and 78 & 91 jets. I did another plug check and there was no color at all on the plugs. It ran great both times but I have been taking it easy until I know the jetting is rich enough to be safe. I seized a piston last year with the Weber 750 due to running lean so I don't want to do that again.

This weekend I am going to take a big jump in jetting in hopes that I can find the "Too Rich" point. I am going to try 83 primarys and 94 secondary jets. I will post my results as soon as I can.

My speed results so far has shown a 2 mph increase just by changing to the Holley. The pain is good.

racinbird

Macdad, Im having trouble tuning my 750 double pumper on a gen vi 502 with same air gap mani, mild cam, and lighting headers. Its got the stock 6.5 pv in it, did changing to the 4.5 make a big difference? Mine has a serious black smoke problem. After sitting a little while and initial start up it puffs a lot of black smoke, almost looks like a small fire on my swim platform! Plus loads up at idle. Im thinking too high float level causing overflow into mani, but haven’t had time to check it. Any ideas on how to adjust float, its at the bottom of the sight hole, did this in the water. Really didn’t have that black smoke problem til I moved it there. Idle pressure is 7-7.25, idle transition slot/throttle plate looks good. Im just looking for any ideas to do here, my arms are getting tired from cleaning all that black sut from my transom. Any ideas would be great!, Thanks

MACDAD260

racinbird, Did you have to move the float level up to get to the bottom of the sight hole? If you raised the float level that would richen the mixture. Mine made the transom black and would load up too, before changing the power valve. I could not adjust it out with the idle mixture screws. The 4.5 made all the difference. It idles good now with no soot. You might want to try changing to a 4.5 and see what happens.

racinbird

macdad, This is a new to me used boat. I just rebuilt the heads and am now tring to properly tune this thing, I have made the mistake of changeing too many things at once without seeing what does what. After all head repairs went on a test run, WOT, shut down to check plugs, engine kept running with key off for 10-15 seconds, i figured lean problem, pulled plugs, white as a ghost! I rasied float level, was close to 1/4 inch below hole, I have jetted from 74p-80s to now 80s-90p in couple size increments, kept playing with mixture screws, highest rpm at idle. Now has hard starts with a lot! of black smoke. It does have stock 6.5 pv installed. The jetting needs lowered a couple, smells really bad according to slower boating buddy. im just tring to get some idea of what to look for and where to go. Thanks, Derrick

formulaF302

Maybe between your problems and mine on above post for jetting on 830 annular carbs we can figure these things out. I'll be eager to read the responses to your problems as much as mine on a daily basis. I even leaned out my floats on secondaries so much that I lost power above 3900 rpm and my plugs are still burning pure black on the rear four cylinders....and my front 4 are showing no color at all. I had some color on fronts and at least had the rear 4 plugs up to dark brown when the jetting was at 91 on primaries and around 81 on secondaries...but everyone told me that is all wrong and backwards so I don't know what to do next.....

Keith

BT knows how much I love my new Holley 800's!!!
<insert a HUGE amount of sarcasm here>

Next time I'll check the forums before agreeing to let a mechanic recommend something other than the dual plane intakes and Quadrajets found on stock merc engines.