I am tearing my hair out with a GMC that needs to be at a D-day event at the end of the week. It has just had an overhaul consisting of a partial strip-down and re-paint, also conversion to 12V, alternator and positive earth, clutch change, and some brake work.
It starts eventually on 90% choke but then if let in even slightly it dies very quickly. It will rev up on 90% choke although it's a bit lumpy. If the choke is pushed in while revved up it sounds a lot better but very quickly and irrecoverably dies. There is a lot of white smoke when it's revved up. I've tested for air leaks and checked fuel supply. I've stripped and thoroughly blown out the carb. The regulator is missing its butterfly so that's not the problem.
When I saw the smoke I wondered about the hydrovac going bad, but it's the same even with it disconnected and the vacuum pipe blanked off. It has been suggested that if that is the problem there may still be residual brake fluid in the inlet manifold thus giving a false negative. This will be my first thing to look at tomorrow unless anyone has any better suggestions?
I'm sure I've seen this problem before but I'm stumped.
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TooTallMike
Dear esteemed team,
I am tearing my hair out with a GMC that needs to be at a D-day event at the end of the week. It has just had an overhaul consisting of a partial strip-down and re-paint, also conversion to 12V, alternator and positive earth, clutch change, and some brake work.
It starts eventually on 90% choke but then if let in even slightly it dies very quickly. It will rev up on 90% choke although it's a bit lumpy. If the choke is pushed in while revved up it sounds a lot better but very quickly and irrecoverably dies. There is a lot of white smoke when it's revved up. I've tested for air leaks and checked fuel supply. I've stripped and thoroughly blown out the carb. The regulator is missing its butterfly so that's not the problem.
When I saw the smoke I wondered about the hydrovac going bad, but it's the same even with it disconnected and the vacuum pipe blanked off. It has been suggested that if that is the problem there may still be residual brake fluid in the inlet manifold thus giving a false negative. This will be my first thing to look at tomorrow unless anyone has any better suggestions?
I'm sure I've seen this problem before but I'm stumped.
Thanks for any suggestions - MG
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