Blowing Vacuum Caps of my Carb....

[MercuryMarc]

I finally got my 69 250I6 to run well with a HW5200. There is no midrange bog at all and I am very pleased. The carb is from a 73 Vega and has many extra vacuum ports that I have capped with rubber vaccum caps. However, frequently on hot restarts the vacuum plugs shoot off their ports! I think I am generating postive pressure and blowing those plugs like little missles!

Any suggestions?

Thanks!

 

[addo]

Backfire through the carb - timing and mixture OK?

 

[saltwaterfalcon1960]

My 1966 200 would not run right the other day.I opened hood and vacum cap was gone.Installed another and ran fine.Must have blew it off,never did find it.

 

[jamyers]

Gotta be a backfire, likely a small one you're not hearing...check the timing at idle, see if it's not way advanced.

 

[MercuryMarc]

Thanks Addo, SWF, and James-
Yes - I did hear a little explosion under the hood and saw some smoke coming from the engine bay one time when the little caps flew off. I have my timing set to 13 degrees and I get no pinging on hills. I am running the DS2 (83 Merc) and have the vacuum advance off manifold vacuum instead of a ported source.

I am still fiddling with the idle mixture screw setting- I am not sure that it's not too lean or too rich.

Thanks again-