OK... gonna cut to the chase.....

Is anyone running a Barry Grant King Demon 1090 straight nozzle carb???

What jetting do you have in it???

We am running Holley 1150 CFM 2-circuit carbs. Assuming the BG's are similar(should be), I think on a NA application the jets should be in the mid to high 80's with PV's. The 6.5 PV's may also be opening too soon. You can find the opening point with a vacuum gauge. We set ours to open at about 80% of the WOT RPM.

Here are the King Demon spec's. Your 94 jets are BG stock, but the KD's are set up w/o PV's. PV's are = to 8-10 jet sizes. I believe you are on the right path if you use the right PV, but you will have to jet down to not be in a constantly rich condition. The Holley 1150 # 7320 is also set up from Holley with 94 X 94 jets w/o PV's.

KING DEMON GENERAL COMPETITION GAS - GC
MODEL # 1090 AD 1090 STD 1190 AD
PART # 8728020GC 8728030GC 8838020GC
VENTURI SIZE: 1.720 1.720 1.812
IDLE AIR BLEEDS: .046 .046 .040
INT. AIR BLEEDS: .070 .070 .043
H.S. AIR BLEEDS: .029 .029 .028
BOOSTER TYPE: ANNULAR STRAIGHT ANNULAR
BOOSTER LEG: .169 .169 .169
SQUIRTER SIZE: 42 42 42
BUTTERFLY SIZE: 2.00 2.00 2.00
AIR HOLE SIZE: NONE NONE NONE
PUMP CAM # 643 643 643
PUMP CAM COLOR: YELLOW YELLOW YELLOW
METERING BLOCK # A-12330 A-12330 A-12330
M-BLOCK COLOR: SILVER SILVER SILVER
SIPHON BREAK: .028 .028 .028
E-HOLE POS. #1 .029 .029 .029
E-HOLE POS. #2 .029 .029 .029
E-HOLE POS. #3 .029 .029 .029
E-HOLE POS. #4 .029 .029 .029
P.V.C.R. SIZE: .059 .059 .059
I.F. RES: .029 .029 .029
T.S. TES: OPEN OPEN OPEN
INT. PICK UP: .040 .040 .040
INT. FEED RES: .046 .046 .063
MAIN JETS PRI: # 93 # 94 #96
MAIN JETS SEC: # 93 # 94 # 96
POWER VALVE PRI: PLUGGED PLUGGED PLUGGED
POWER VALVE SEC: PLUGGED PLUGGED PLUGGED
LINKAGE TYPE: PROG. PROG. PROG.
N&S SIZE/TYPE: .130-VITON .130-VITON .130-VITON
ACC. PUMP DIA. SIZE 50 CC 50 CC 50 CC

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Thank you Ben.....

Exactly the info I was looking for. I will let you know how it works. These are blower motors minus the blowers what effect would the lower compression pistons have on carburetion (jetting P/V)?

Randy

Our CR is at 9.3 to 1. Not positive, but I don't think the CR will impact the jetting. Anybody? Many/most the single plane intake manifolds seem to make cylinders 1&3 and 2&4 richer than 3&5 and 4&6. We are still tweaking our jetting but currently we are still richer on the front cylinders (reading the plugs) with a 88(R) X 85(F) jet pattern + PV's. My thought is for you to consider starting your jetting here and then run 5 min at 3,000-3,500 RPM and look at your plugs while still on the water with no idle time.
The fun part about a carburetor is you can do most the work yourself and get measurable results :drink:

Getting close on jetting, 88p and 94s What power valves are you using? All I had were 88 and smaller mains, I would like to go smaller on the secondaries ...... Starboard motor quit after 10 min. I thought its was the MSD box, that was what it felt like, just quit, turned out to be coil wire and coil tower burned off???? WTF would cause that?? No one I have talked to or shown it to had an idea why.

Are you on the dyno or in the boat?

Boat, I bought the boat this way .... it sat 2 years. I plan on pulling and dynoing this winter

I had the same issues with my BG King Demon. I took a carb guy with me to the lake to tune it.

Make sure your floats are not sticking. I had this issue as well.