AQ125A Backfire

[heathstallings]

I have a 1984 Volvo AQ125A with a 270 outdrive. The engine runs smooth most of the time, but I am experiencing a random "pop" or backfire noise coming from the carb on occasion. It does have a tendency to backfireand run rough under a load when the engine is cold, but it has started to continue as it warms up. Other than the occasional backfire, the engine runs great once it is up to operating temperature. Any ideas?

 

[Don S]

Re: AQ125A Backfire

When was the last time it had a full tuneup? Have you checked the fuel system for water? Do you have a water separating fuel filter? If not, you should consider installing one.

 

[heathstallings]

Re: AQ125A Backfire

It had a tune up at the end of last summer. It does have a water separating fuel filter that I installed this year.

 

[Mullin]

Re: AQ125A Backfire

A backfire is going to be caused be either out of service ignition components, improper air fuel mixture, or improper timing advance.

Since you had a full tune up at the end of last year the components should be fine but maybe timing was not reset properly. Check timing advance and dwell and if that checks out then try adjusting your carb's mixture screw.