Ok guys I am looking for some help on dialing in my single 1050 Dominator. The carb has been boost referenced and the current jetting is 92 for the primary's and 92 for the secondarys. She is sitting on top of a TBS 250 Blower with a 540ci stroker. As I start giving her stick she she lights up and wants to run hard, but around 4100 she starts laying down. I know I have a problem with my fuel pickup being a 3/8" tube and will have to address it with 1/2" pickup, but that should only affect longer run times. I know I have enough fuel volume to handle shorter runs the fuel pressure barely drops below 8.0 lbs when i give her a full stick of throttle.

Blownhavasu and myself took her out yesterday the air was a mild 102 water temp was a cool 67 we cruised for a while letting the oil temp warm up and when she was ready we ran her hard and produced around 4lbs of boost till she started laying down . We immediately pulled a plug and the ground strap showed heat, however the plug looked lean. We built this motor to run around 5600rpm with 750hp. I know this monster wants to run you can feel it and hear it. What do you guys think the jetting should be?

We think we should start by jumping the secondary's to 98's and then adjusting accordingly. Unfortunately I will not be at the boat till next Friday and would like to get a variety of jets. Can someone tell me where I can purchase them and get them delivered to California by Thursday.

Thanks.

ttt

Just guessing, I would say it's lean. My 540's with 1050 Holley uses 90 primary, 92 secondary.

Is your 540 blown with a single dominator?

The fuel pick-up is of major importance!!! I had my fuel tanks replaced and experienced the same "laying down" you did, and lost 500 rpm. I took the pick-ups from the old tanks and sure enough I was back up to 5300 rpm and motors ran great.

My motors are procharged 502s with head porting, running 5+ lbs of boost. My jetting is 78 primary, 96 secondary

Hope this helps

Call Dean Nickerson.

No n/a. That's why I'm guessing you're lean. Summit and Jegs sell jet assortments on a card. You get a pair of each size from 80 to 90, 90 to 100 etc. They could get them to you on time, even over night.

Ran her again this weekend and changed the jets in the secondarys to 98's and i gained 10% i made it to 5000 rpm's and she started to lay down again. We looked at the plugs and she just was starting to creat some heat, so I changed the primarys to 94's. Ran her again and she once again started to laydown at around 4200.

Changed the plugs went back to the primary's at 92 and changed the secondarys to 96's. No gain was seen and she started to lay down at 4100.

My question is when i first changed the secondary's to 98's i saw an increase in performance and she started to gain some heat which was good. But when i changed the primary's to a bigger jet she stated to lay down. I realize that becuase this is a boat and we idle at low rpms's we need to have smaller jets in the primarys so we do not foul plugs. How do we feed the right amount of fuel to the motor with what jet combinations on a single blown 540?

I originally purchased the carb from CPPerformance and gave them my engine requirements, they sent the carb to Blake Carbureation in NC. I spoke with these people and they are the nicest people, but informed me that they mostly do race cars and until recently have done a whole lot of carbs for boats. That would explain why it came with 92's in both the primary's and secondary's. That would be the perfect setup for a race car.

Anyone have Dean Nickerson's number. I am going on vacation this Friday and will have an entire 10 days to tune this sucker, so any advice will definitely be appreciated. I am going to lake shasta in Northern California and i believe the elevation will be around 11,000 i guess. I usually boat at 500 ft above sea level in Lake Havasu AZ.

PatriYacht thanks for the 411 on getting the jets.

PureEnergy, I am curious when you were losing RPM's did you fuel pressure drop, mine is still showing 8lbs.

thanks guys.

I think you are wasting your time with jetting until you fix the fuel supply side. I had a drag boat that had the same problem. I was up to 140's and still flattened out.I went up to 9/16 line without any success. Finally was told to open up the air vent on the feul tank and the problem went away and I went down to 95's.This was in an 11 second 1/4 mile with a very light flat bottom (no hull drag). Fix your pick up and check your tank vent or you will be doing all the work again.

My fuel pressure did not drop! It was very frustrating to diagnose.