Saraalvis Posted February 6, 2023 Share Posted February 6, 2023 Help needed please. My recently purchased Saracen has started backfiring, badly, and is generally not very well. The engine , Rolls B80, was running sweet but all of a sudden started running rough. Where would you start and anyone with ideas? Thanks, Matc 1 Quote Link to comment Share on other sites More sharing options...
fv1609 Posted February 6, 2023 Share Posted February 6, 2023 Obviously you have clean fresh fuel. Based on my experience of similar with B60 I would check that the fuel filter is not full of crud, check that the bleed valve on the fuel filter is doing a proper job & not allowing air in. Test or replace the distributor condenser, with a new one, do not buy a NOS one as by now they will be very old & the insulation will have deteriorated. Check that the CB points haven't closed too much. Check the sparking plugs to see the state of deposits around the gap. File & clean & adjust as needed, but do not attempt this on the RSN13P plugs as you could break off or weaken the platinum side contact. 1 Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted February 6, 2023 Share Posted February 6, 2023 I would do a compression test on the engine while plugs are removed as the head gasket could have blown between two cylinders. Not unusual on B60 and B80. You will know if it has because two adjacent cylinders will be a low reading and identical pressure. Quote Link to comment Share on other sites More sharing options...
AmmoMan Posted February 7, 2023 Share Posted February 7, 2023 Could just be too much fuel, check the cold start (choke) is closing properly i.e. manually push it on the carb all the way closed as they can stick open. Quote Link to comment Share on other sites More sharing options...
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