Yamaha 8hp has no sparks

[JACKTAR2005]

I have a 1977 Yamaha 8hp outboard which has been in long time storage.
The motor has had about 30 hrs. use and is in 'good as new' condition. It has been regularly turned over buy not fired up.
I have managed to check all coils including the 2 ignition coils for continuity but have yet to find a spark.
I have been unable to find information on 8hp Yamaha motors prior to 1984. Where can this info. be found preferably with a wiring diagram.
Could the long storage cause the flywheel to lose its magnetism. ( I ask this because I also have an a 1979 Seagull which required a replacement flywheel before it fired up )
I would be grateful for any advice on this problem

 

[VicS]

I have a 1977 Yamaha 8hp outboard which has been in long time storage.
The motor has had about 30 hrs. use and is in 'good as new' condition. It has been regularly turned over buy not fired up.
I have managed to check all coils including the 2 ignition coils for continuity but have yet to find a spark.
I have been unable to find information on 8hp Yamaha motors prior to 1984. Where can this info. be found preferably with a wiring diagram.
Could the long storage cause the flywheel to lose its magnetism. ( I ask this because I also have an a 1979 Seagull which required a replacement flywheel before it fired up )
I would be grateful for any advice on this problem

Stop button OK ?

What do the coils look like. Insulation look OK. Continuity is only half the story. Shorted turns or bad insulation will kill them.

Is it points ignition. If so are the points cleaner than clean and correctly adjusted.. Condensers possibly dodgy.

Would be nice to check for an input to the Ht coils but you need a DVA adapter on a multimeter to do that.


Worth checking the magnets I suppose but its only Seagulls I have heard of losing their magnetism....... there's a quick fix for those.

Mariner engines from that period may be the same!

 

[cliff]

Worth checking the magnets I suppose but its only Seagulls I have heard of losing their magnetism....... there's a quick fix for those.

I had a 25hp Johnson did the same - flywheel demagnetised so no juice for the coils so it is not just old seagulls that suffer.

 

[winsbury]

If a magneto has lost magnetism, attaching an electric drill to the flywheel and taking out the spark plugs first will restore the magnets after a few minutes of spinning over as the coils work as remagnetisers from any weak magnetism left in the system. The spark may still be weak but will improve when the engine is run at full pelt for 30 mins or so.