Sputtering, gasping, coughing 912!

[doctor dave]

My 1969 912 when starting and for awhile after, coughs and spits from the drivers side carb. I hear this is a good sign I need to have the carbs rebuilt but I am wondering if there are any quick things that need to be done/checked first as a solution.

-gets better when warmed up and does not gasp when at driving RPMs
-idles pretty good even when cool
-the worst is when cool and around +/- 1000 RPMs
-no coughing from passengers side carb

Any ideas?

Thanks, Dave

[Jerry1]

Hi Dave
Question Are you using webers or solex? Have you done any work to the carbs resently? Has it ever ran right? A few things to check would be fuel pressure. Are you using a electric fuel pump or stock? Change fuel filter. Bad base gaskets may be leaking. Just a few thing to check.
Jerry

[JT912]

I'll assume you've also properly adjusted your valves?

[neoneon]

Hi dave
My '68 does something similar. Same pattern of worse when cold. Engine also quakes in range of 11 to 1500 rpm. Will be doing a tune up ex carbs and will update.

Dana

[Scott Douglas]

Start with what John says and work from there.