team Tickfaw

Hope someone with some knowledge of edelbrock carbs can help. I have twin 454's dynoed at 435 hp for one and the other 450 hp. Carbs were purchased new when engines were built. The carb that is on the lower hp engine bogs when trying to get on plane and sometimes "coughs". You have to give alot more throttle to this side until it planes and then back down on the throttle to get the rpms back even. When running seems to be fine. Also on the lower hp carb, looking into the throat of carb and on breather there is alot of soot. Other side is clean.This is my first experience with edelbrocks and do not know what to look for or how to adjust. Carbs are 750 cfm marine and have 6.5 psi fuel press. Thanks for any help.

ghittner

Have you checked the timing on the problem motor? Just to rule that out.....

CrazyCat57

Check with edelbrock they have a tech line 800 416 8628 but I am quite sure that 6.5 psi is too much for a edelbrock carb. Edelbrock say's 4.5 to 5.5 psi max or gas can flow past needle and seat. Check your choke setting, if it is set to strong the secondary's will not open.

nwimbush

I have to ask - when did you get them dyno'd, and why is the hp so different? - the dyno results will give you a good idea of where in the rpm range you're having A/F or timing issue.

Assuming identical carb/timing/engines I would look to dirt holding open one of the power valves - easily accessible under the teardrop plates on the top of the carb. Undo the philips screw until the plate slides 90 degrees - the power valve will pop up. Gently remove both the needle and sleeve as a unit. Both sides.
I prefer to use my shop vac with a tee-shirt as a filter to clear crap out while it's on the boat.
Gently reinsert the needle valve/spring/sleeve assembly, insuring the retaining sleeve is seated fully. Press down lightly on the needle to ensure it seats properly - vacuum holds this baby down, so it needs to seat effectively.
Return the plates and tighten the philips and you're ready to see what;s what!
Hope this helps...

team Tickfaw

Thanks for the idea's. The reason I have 2 different hp ratings is that 2 different shops built the engines. Long story but I wrote about it here last year when having cam problems. Turned out to be mechanic problems. I do have a regulator that I can put on and try. I will do this next weekend. On the timing I have not verified it in 6 months or so. When I got engine back I was told to run it at 28 degrees at full advance. That seems low to me. I will also try the cleaning. Chokes are unplugged and tied off. Thanks for your help!!!

CrazyCat57

A talk with edelbrock may save you time and headaches. The tech guy's know the carbs inside and out and may suggest some other things to check.

team Tickfaw

Talked with edelbrock tech. They said same thing about the fuel pressure. Just did'nt think I needed to put regulators on stock mech feul pumps. Looks like thats what I need to try though. Thanks for the help.