InstaGator

I'm running a fresh Gen VI 454/330 complete roller motor, Holley 650, Mallory Unilite optical distributor, 4" Stainless Marine exhaust and a labbed Rev 4 22P prop. The motor should be turning 4600-4800 RPMs. The best I have been able to turn is 4200 @ 46 mph. I'm still 400-600 rpm short of where I should be. Any help would be greatly appreciated. Would a high rise manifold & a bigger carb make a difference? Maybe a different distributor? I'm at a loss at this point.

picklenjim

Mild cam, Edelbrock RPM Air Gap intake, 750 Edelbrock or Holley carb and a bigger/better flame arrester. What's with the fuel line running up to the carb. Is that an electric pump up there?

InstaGator

Thanks for the reply. Yes, that is an electric fuel pump. Gen VI has no mechanical fuel pump boss and requires an electric fuel pump.

FIXX

iTrader: (2)

for one you need to get rid of the advance auto mr gasket fuel pump and get a mallory 110 gph minimum..electric fuel pumps are designed to push fuel not pull it..the pump needs to be close to the fuel tank so you will need to mount the fuel pump closer to the tank along with the filter in line before the pump..

the unilite distributor needs to have a ballast resister going to the eye..you can only put a maximum of 8 volts to it,,if you have power straight from the ignition switch you will burn out the electric eye in no time..did you set the advanve in the dist?? whats your timing at now?? also that carb looks like a 600 cfm,if it were me i would start looking for a holly 750 cfm..that plus the fuel pump upgrade should give you more power ..

picklenjim

Another option you would have is to switch your seawater pump to the seawater/fuel pump. That's what was used on the Gen 6 carb engines. Here's what they look like. Toggle through the pics and you'll see how it mounts.
http://www.ebay.com/itm/MERCURY-BOAT...8152e3&vxp=mtr
This way you could elimanate all the electric pump crap. Need to use some elbows in the plumbing to get rid of all the big loops in the fuel line. Run an elbow coming out of the filter/seperator and run the line up on the left side of the thermostate housing. You got about 3 times as much line as you need between the filter and carb. Looks scary.

Thats a pretty good size boat for a relativly stock 330. Appears the only real upgrade is the exhaust, but that's a good thing. I believe the Merc max rpm spec for a 330 carb engine is only 42-4600rpm's.

Something else I would do (just my opinion) is get rid of the remote oil filter setup just to elimanate any possible leaks or problems and make it look cleaner. All the room you have around that engine you would have no problem just hanging the filter on the block. Use a big 2qt Wix.

Fenderjack

iTrader: (2)

Have you checked the timing? Hell my stock 330-350 bbc's are twisting a 25p to 5k no problem.


John jr

InstaGator

I may have to get away from the Mallory Unilite optical distributor and go to a vacumm advance distributor. I'm looking for a bigger carb, a Holley 750 cfm. I know that I should be able to get max rpms somehow. I feel like a dog chasing its tail...

FIXX

iTrader: (2)

vacume advance dist is not uscg legal..plus a uscg carberator must not have any vacume ports..the unilite works just fine,,i had one in my boat for 12 yrs and did not have any issues..you just have to know hot to take them apart and how to se the advance up..

the deep

iTrader: (8)

I'm with you all the way on this one fix . Great advice .

Mbam

Back in the day I always ran the Unilites, but after a while I learned the hard way that the advance mechanism would self-destruct. Probably fine at that RPM, we used to run them over 6000. Wouldn't hurt to take a careful look at it in any case.