Weber Carb and Dieseling

[eastendmedic]

87 60 with a webber carb.....had to repace the inline fuel pressure regulator as the old one was leaking fuel all over the manifold....anyway used to diesel until I adjusted the timing and idle.....it went away....now that I have replaced the fuel pressure regulator it is dieseling again......nothing else has changed......timing at the BB mark, idle 650rpm at temp.....there is no fuel cutoff solenoid...so that can't be it....temp is within normal range....Any Ideas....Help....it is driving me nuts!!! Thanks.

 

[REKCUT]

I have a weber carb and my truck diesels if I use low octane gas. I dont know why but with higher octane it runs perfect. I have seen several other remarks from people with webers that also have the same issue with low octane. Try one tank and see if it works.

 

[stinkyfj60]

I run the lowest octane I can in my Cruiser with a 38mm Weber on it with no dieseling at all. I am not sure how to help you but I wouldnt think octane is the answer, the compression ratio is too low on a 2F.

 

[natdog37]

I had the same problem with my 82' pu. somebody told me that there was too much gas in the bowls? I have no idea if this was the culprit but just thought I'd add my 2 cents.

 

[Roebon]

I think the float level is a good place to look. Could it be that the excess pressure from when you ran without a regulator through things off? I would reset the float and eliminate that as a possible source.

 

[eastendmedic]

Think I found the culprit...a little advice needed.

So I decided to do a Texas Rebuild as specified on this forum...lots of black crap out the tailpipe used about 1/2-3/4 of a can of gumout......so I decided to check for an intake leak and sprayed a little gumout at the base of the carb nearest to the engine....sure enough.....the idle crapped out and ran really rough...I believe that that indicates not only a leak but a rich condition...Little help here Jim C.....anyway...it has been raining for the past three days and I haven't been able to get around to really investigating the leak and the mixture of the carb....I will have to reset the mixture for lean best idle and tighten the bolts on the carb....

Could and intake leak at the base of the carb cause post ignition?

Could the Rich setting on the carb cause post ignition??

Thanks.