edelbrock 1409 on 4.3 mercruiser

[pwpns]

I have a 99 stingray with a 4.3 mercruiser I put a comp cams 268HR cam and edelbrock performer intake and 1409 carb with a 1485 calibration kit(.089 primary .089 secondary a 68/57 metering rod and pink 7" spring) . The engine is backfiring and sputtering when you get over 2000 rpms (indicating lean condition) I put .092 primary jets in it and is seem to help a little which I noticed was the jet size for the weber carbs. I was wondering if anybody knew what the mercruiser metering rod part # 16-686457 releated to in edelbrock and how much vacuum on the mercruiser green spring. Also wondering if anybody has just run one on a 4.3 without the calibration kit and had any problems. any advice would be gladly welcomed. Also changed the fuel pump tested the system and it is not airlocked and produces 7lbs of pressure. Thanks

 

[John_S]

Re: edelbrock 1409 on 4.3 mercruiser

the mercruiser metering rod part # 16-686457 releated to in edelbrock

That is a special 3 step rod, that will only work in the mercruiser webers from mid-90's. The edelbrock just uses the standard 2 step.


The 4.3 kit from Edelbrock matches the Mercruiser weber specs from the pre-vortec 4.3L. With vortecs and a cam, expect to make some changes. Someone here did tune a 1409 to a slightly built 4.3L. Maybe they will jump in and provide a possibly better baseline calibration. Otherwise, just go through Edelbrocks tuning guide, step by step.

 

[wca_tim]

Re: edelbrock 1409 on 4.3 mercruiser

7 pounds is marginal for that carb in my experience. double check that there is no fuel dripping when you're at idle.

I wound up going a little richer than that when i dialed one in on a 4.3. I think I had to go another couple steps richer for cruise mode and one step for power mode (in the edelbrock table provided in the owners manual...). The edelbrock instructions are pretty good and work if you follow them.

You might also need a different spring - that can make a huge difference. check your vacuum at idle to be sure...

Hope this is helpful