Backfire through carby

[Bryan Wilson]

My 351W with holly 600 backfires back through the carby when the engine is cold. The problem is gone once the engine is at normal temperature.
Any idears on the cause or remedy would be welcome.
regards,
Bryan Wilson

[Hotfingrs]

Bryan

Are you running a choke. I don't and mine backfires til it's warm. Solution is to keep the rpm's up for a few minutes until engine gets warm.

If you are using a choke, check the settings and make sure that it's working, and also see if you can get it to close a little more, to richen the setting

Don't know if you have the houseing on the side with 3 screws to hold choke adjustment....but if you do loosen them a little so you can turn it. There should be marks on it for reference points. Just richen it a little at a time to make sure your engine will run when cold.

[Bob Putnam]

Bryan,

It's not necessarily anything wrong.

This is quite common on cold engines without a choke. If you have mechanical lifters, you might check clearances though - tight valves exacerbate the condition a bit, as does retarded ignition timing.

[Bryan Wilson]

Thanks to those that replied to my question.
I have now installed a manual choke cable and made the choke operational. Now all I have to do is remember to push the choke knob in when the engine warms up.
Many Thanks,
Bryan