Do these vacuum reading sound resonable for 5.7GS

[jgresham75]

I have 99 5.7GL with new long block and new Holley 2300. Trying to set up carb. I have gotten idle mixture, idle speed and timing down and it idles great. Now I am focused on turning after idle. I got a bog off idle. I can go slowly up to speed so I am working on setting power valve and accelerator pump action but focused most on power valve.

Do these vacuum readings sound reasonable?
1. At idle, I have 17.5" at 650 rpm using manifold vacuum at about 8 degrees on timing. Idles great. From other information I have obtained, that sounds good for a car motor but should a marine engine exhibit the same vacuum at idle?
2. Under load, vacuum fluctuates between 9-12. Does this sound appropriate for marine engine? In trying to set power valve using either half of idle vacuum or 2 down from load vacuum, that would put a power valve at around 8.5. Manual says 4.5. Does having such a larger power valve from manual sound right, even though it is based upon actual vacuum readings? I am running a 7.5 power valve with a slight bog so based on this, the 8.5 may resolve bog.
3. Under load, as mentioned above, the vacuum gauge fluctuated by about 3" from 9-12. Does this range of fluctuation sound normal under load? At idle, vacuum stay very constant within about .5".

Thanks for your help. Not real savvy on carb tuning but I am learning.

 

[Maclin]

Is it a Marine 2300? If so, what PV was in it? Go with the 4.5 PV as it is more appropriate for the duty cycle the engine will see. I would go a a half turn or so back to the rich side on the idle air adjustment, that will help some with a lean bog. Does this have the 50cc pump? Is the lever adjustment correct, meaning lever acutuates the pump diaphragm immediately? The clearance setting is to be done with throttle plates open, needs clearance then to keep from punching thru the diaphragm. What# squirters came with it?

 

[jgresham75]

Marlin, Thanks for your input. It is a marine 2300 with the 50cc pump. I put the 4.5 back in and adjusted the idle mixtures and will try later this week. I think one issue I am not sure of is how to adjust the pump lever.