Running rough on start up, carbs ?

DamianZ28

Active Member
Hi All, I've covered a small amount of miles since the full engine rebuild, say about 32..was running fine but now on start up from cold, its sound like its running on about 6~7 cylinders. I thinks its the carbs again, last summer while the engine block was away at the engine overhaulers I stripped and replaced all the gaskets, rubbers, 'O' rings ect, didn't change the floats or jets thought, have fitted new needle holders, everything was cleaned & reassembled. If I pull the choke out then it'll stop, no rise in revs at all, could it be the one of the floats are knackared/ punctured ? could the old jets be worn ? Sounds better on higher revs though.
I have to replace the oil pump as fitted an uprated version as I did several yrs ago to my old P6 but on this one I stupidly removed a small amount from the bottom of each new gear & created the smallest amount of end float so once the oil is hot its loses it pressure, there should be no movement at all as its an extremely tight tolerance fit once the oil pump cover is back on so I'll need to replace these and fit correctly without any end float. I may just fit the old gears back in as still have them, the updated version is basically the same with taller gears, same as the SD1 version, the kit provides a same shape spacer which fits to the housing once correctly shimmed, I know the original pumps weren't great but they weren't terrible either, I have fitted a new tadpole style oil pressure relief valve & new spring, So not driving at all at the moment due to this & crap running :-(
 
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It does certainly sound as if you have not set your carbs up correctly, or something else with them is wrong. Have you tried using the lift pins once the engine is warm? What did you find? How many turns below the bridge did you set the initial jet height?

Ron
 
Hi Ron, thanks for the input, yes the settings are as per the manual advises, once the level with the bridge l wound it back 2.5 turns, the needles when lifted didn't seem to alter it much but definitely something not set up right, do you think a worn floats and worn jets could potentially effect it?
 
Hi Ron, thanks for the input, yes the settings are as per the manual advises, once the level with the bridge l wound it back 2.5 turns, the needles when lifted didn't seem to alter it much but definitely something not set up right, do you think a worn floats and worn jets could potentially effect it?
You should wind it in (clock wise)
 
My very poor running was choke O rings, and in the end I used the book method to set mix. Ended up with mix screws in 2-7/8 turns and it starts and runs well....although lately have an occasional stall with choke fully home. Suspect idle stops slightly inconsistent, or a linkage problem. I found it very useful to reset the fast idle setting so that choke is out ~1/4-3/8" out.
Did you do needles & seats? Are the jets the handed types? Assume you have HIF6 carbs, if not ignore the last question.
 
Hi All, sorry yes I meant say I wound them in clockwise, I didn't do needles & seats or Floats, jets so possibly these one of these have failed.
I need to re~check all the settings step by step, yes they are the later HIF6 carbs.
 
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