Carb Tuning

[FreeBeeTony]

I am in the process of breaking in my new engine.

There is a definite vibration, being caused by running rough between ~1500-2500RPM. Once I am on plane (~300RPM) and cruising it smooths-out.

I have the Edelbrock 1409 carb.......I know the springs can be changed to determine when the needles (correct terminology?) open.

Can I determine if this may be the problem by slightly closing the choke when the engine is operating under these conditions?

Also, how important is the adjustment of the idle c ircuit at 1500-2500RPM?

 

[FreeBeeTony]

Re: Carb Tuning

Going down to the boat now to check the idle mixture with a vacumm gauge.

 

[John_S]

Re: Carb Tuning

Tony,

I am sure Bondo will jump int with some Edelbrock tuning tips. But, I wouldn't think the idle circuits would be contributing to rough running at that rpm.

I think you had this carb running on the 350 mag/vortec. If it was fine there, I wouldn't think it would need a retune for your Rapido vortec. I would think just a idle mixture and idle speed adjustment. Neither, should have been that grossly out to cause mid range problems. It might mean you have and installation or storage issue. You might have a vacuum leak that you should be able to detect with your gauge. Also, maybe something got gummed up in the carb if some gas was left in it.

 

[Bondo]

Re: Carb Tuning

Ayuh,...... Tony,... Do you have a Kit, with springs,+ needles,..??

If you can bring it back to smooth by Choking it,.... It's too Lean....

Do you have the link to the tuning Manual,..??

I agree, you're Out of the Idle circuit by that time,....

 

[FreeBeeTony]

Re: Carb Tuning

Just got back from another ride............can't get enough right now. Engine seems so smooth and strong.............have now gone up to 4000RPM!.......only 3hrs on clock............had the same vibratioin with the previous engine.

 

[FreeBeeTony]

Re: Carb Tuning

Probably going to wait until break-in is complete beforte fooloing with carb...........seemed to smooth out some after I adjusted the idle.......

 

[Fishermark]

Re: Carb Tuning

In a previous post you mentioned the possibility of picking up some water in the fuel and changing the water separator. If you did in fact pick up some water and other "junk" some of it may still be in the fuel bowl of the carb. It wouldn't hurt to take it off and check it out.