Help 25hp Johnson 1976

[David_Dickens]

I have just bought a small secondhand run-a-bout with a johnson 25 hp 1976 model advertised as VGC .He lied >:(
Any way to the ploblem , It only fires on 1 cyl at a time. I have cleaned and set the points, put new condensors in and new plugs. The bit thats confusing is the top cyl fires on 1 start then the 2nd may fire on the next start but only 1 fires at a time.Any help would be great.

[NQCairns]

It's hard to answer without seeing the motor, but have you got it to start at all and run til warm? It doesn't make sense th

[NQCairns]

Dont know what I did wrong there anyway - It's hard to answer without seeing/hearing the motor, but have you got it to start at all and run til warm? It doesn't make sense that it would just decide to do what you are saying each time - it may just seem like it. If you have a compression tester try that to see if there is a problem if you dont have one try pulling both sparkleads and one plug then stick your finger over the plug hole and pull start (on a dead motor) taking note of the push/suction on your finger then swap plugs and do same if one is fairly different then you have a comp/vacume problem and need teardown at some level. It's rough but it works for real problems. Sometimes motors just need to get running and a rough way of getting out of trouble is to use Aerostart to get it kicking then choke or not the death out of it at full throttle and place your hand over the carb mouth until almost dead then remove unill revs pick up then try again all the time at or near full throttle, this has fairly consistent results at clearing minor carb blockages etc.

It's your call, theres many things that can give strange symptoms, but keep it simple and start with any spark at each plug - if both do spark (at all, even weak) when earthed to block, then go for fuel and make sure it is getting what it needs (tank,lines,fittings,bulb) if it is then go for the spark timing and see if that is ball park if it is then go to back to fuel and check deeper at carby level, this can include the reeds, then if still no luck check deeper into compression/vacume, this can also include the reeds. Anyway I was probably no help but hope you get there. Nqcairns