engine bogging issue

B

barracudababy

Member
Hello all, i recently posted a concern i have with my 74 Z50 which developed a bogging when the throttle is opened up. It had run fine and i had taken it apart to replace the kick shaft and since it does not want to run past idle. I posted and the responses sugested it may be timing related so I replaced the points and cond. set points at approx .014 and the timing mark is almost bang on on the cam gear. It will start and run fine but when opening the throttle it bogs so last night while fiddling with the carb screws i found it would run with the choke lever almost at full choke, but not very well at least it will take throttle.
Any ideas on what might be my problem. I appreciate the feedback i have gotten so far and hope to repay the favours.
thanks
 
check for an air leak/overly lean mixture. Look for a leak either with a stethsescope (the thing the doctor uses to hear your heart) or spray carb cleaner at the carb/manifold and manifold/head mating surfaces. Idle will increase.

For finding if its lean, theres always plug readings (dark=rich light=lean gray/tan=normal) Or an old school jaguar tuning trick where you have a hose. put one end at the throat of the carb and the other at your ear. you should hear sucking of course. If you hear sucking in air and every now and then it stops and sounds like it sucking in a liquid, its rich. It should be just past that point, a nice strong sucking sound.

I know it sounds stupid but it works ive tuned drag cars like that.
 
so i checked the carb and intake for leaks and found none. I wondered if this might be afloat issue? I adjusted the needle clip down 1 notch which raises the needle more and didn't help, the only thing that makes it run half decent is having the choke lever almost to full choke. I assume that means a lean condition?
Any tips would be appreciated
 
Call me crazy but in order richen the mixture you need to move the clip up to put the needle deeper in the carb, therefore allowing less air to flow through. Anyone correct me if I'm wrong.
 
incorrect.raising the clip drops the needle in the seat leaning it.lowering the clip from the middle,usually where it is factory richens it.
 
unfortunately I don't know how to post pics on here, i took a couple of where the cam mark is in relation to the mark on the head, it is slightly above the mark, I will try and adjust the cam to the next link but it will likely be below the mark on the head then, but is worth a try.Thanks for the feedback
 
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