Carb help

Reply Subscribe

Thread Tools

07-08-2014, 09:32 AM

#11

flat rate

Platinum Member

Thread Starter

iTrader: (3)

Join Date: Apr 2005

Location: St.Peters,Mo/5mm LOTO/LEOPA

Posts: 1,227

Likes: 132

Received 136 Likes on 81 Posts

Engines were new last year. Has been like this since new. Been real busy and havnt had much time to get it dialed in. I think the air bleeds are my next step. Just looking for suggestions to try next weekend when I go back to the lake. As far as the vacumn goes both engines are the same. And they have a very aggressive idle. Engines make 620 ft lbs at 4800 and 608 hp. And hp keeps climbing to 6000. Engines are being run at 5300 -5500 rpm.

07-08-2014, 10:17 AM

#12

BenPerfected

Platinum Member

Join Date: Dec 2002

Location: Dallas, TX

Posts: 2,195

Likes: 0

Received 2 Likes on 2 Posts

Quote:

Originally Posted by flat rate

I'm having trouble keeping my engines running in gear . It is idiling at 1000 rpm out of gear and drops to 550 in gear. They are 540ci 600 hp 950 quick fuel carbs. 35 total timing with black bushing in dist for more initial timing. Makes 5 inches of vacumn at idle. I don't have experience tuning using the air bleed jets. I would like it to have another 100 rpm or so in gear for a stronger idle. It smells fat at idle but if I turn the idle screws in any more it doesn't idle at all in gear. The engines were dynoed and perform flawlessly everywhere else. Just looking for any suggestions on the weak idle in Gear. I have also drilled a .040 hole in each throttle blade that did help.

We fought the stalling issue for 10+ years and tried every option we could to get the RPM spread lower that 500 RPM between in and out of gear without stalling. We finally fixed it last year with these new Holley Gen 3 Ultra carbs. It is kind of like the carb "knows" and won't let you stall. It is available is various sizes. I little pricy, but worth twice the cost. We also ordered J tubes as separate part as Holley hasn't offered this series of carbs in a marine version.

http://www.jegs.com/p/Holley/Holley-...36511/10002/-1

07-08-2014, 02:46 PM

#13

ezstriper

Registered

Join Date: Nov 2005

Location: Fredericksburg, Va

Posts: 4,554

Likes: 0

Received 2 Likes on 2 Posts

1st thing I would do is run the dist locked, set at 34 and you will notice a big improvement in idle quality, also I bet if you put a timing light on it when you put in gear you will see it fall even lower than you 17 initial and start moving around making it even worse...with a good gear drive starter should not be a issue starting, if you do you can run a MSD start retard but would try without it 1st..