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Collection, Preservation and Display of Old Lawn Mowers

Ransomes Fourteen / No spark

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The BSA F07 engine on the above machine has just about developed every complaint known. 

1. I have completely cleaned out the carb and petrol supply and now have a good supply of fuel. Engine ran well until hot then died, no spark , new plug fitted.

2. Main shaft Oil seals have both been replaced as oil was evident in mag and at drive shaft end. Piston and cylinder are not bad, new cylinder head gasket fitted, and valves etc ares working OK.

3. Now no spark so after cleaning everything down have fitted a new condenser, Still no spark.I take it the wire from the condenser is supposed to be trapped in the silly junction box where the CB points wire and the coil wire are connected????

4. Does this now mean  its probably the coil that's faulty or the HT Lead?

5. Can't think of anything else Can you?????

 

 

 

 

 

 

 

Forums

wristpin Sun, 09/06/2019

Simple (cheap) things first.

Try a different plug.

Test for a spark off the bare end of the HT lead  - not the connector. Spark there, new connector or unravel a paper clip, stick one end into the lead  and wrap around the plug terminal 

Are the points really clean? Pull a piece of clean white copy paper through them , but not right through so that the points grab unwanted fibres. Open the points to release the paper.

Was the condenser NEW or just a different one?

Double check the connection between the points, coil primary and condenser and make sure the the end of one wire is not earthing out. 

At this point it starts to point towards the coil  - get the coil tested.

 

layzeefox Sun, 09/06/2019

New plug, new condenser, clean parts, can't see any earthing problems so looks unfortunately like the coil then, sounds expensive? Thanks for your help,