Lost spark for no known reason late 70's Mariner (50HP)

[ba_50]

The last time I started this motor there wasn't a problem. It is still on a stand and there isn't any spark on two plugs, probably the third one too.

So if I never hit anything (flywheel key should be ok) and in neutral what else could it be? Thanks.

 

[Laddies]

Re: Lost spark for no known reason late 70's Mariner (50HP)

If we had a serial number, we can help they had a couple of differant systems

 

[ba_50]

Re: Lost spark for no known reason late 70's Mariner (50HP)

The numbr on the block is 0244350. That's all there is.

 

[Laddies]

Re: Lost spark for no known reason late 70's Mariner (50HP)

1. make sure the engine is turning at least 250 RPM
2. disconnect the blk/yellow wire at hh the switch box and ck for spark--spark means trouble in the kill circurt
3. disconnect the yellow wires from the rectifier-- spark bad rectifier
4. Ck the stator--need to know if it is a flex plate or cast flywheel to give specs.

 

[ba_50]

Re: Lost spark for no known reason late 70's Mariner (50HP)

I don't know what the flywheel is made of and I can't get it off with a regular puller. So no way to check the stator. I don't know how fast it was turning when I checked the Blk/yellow wire and yellow wires but still now spark.

 

[Laddies]

Re: Lost spark for no known reason late 70's Mariner (50HP)

If the flywheel has 2 rings of 1/4 " bolts hold it together it is a flex plate if it is cast in one piece it is a cast flywheel neither needs to be removed to test the stator that is done with a DVA or OHM meter on the wires at the switch box

 

[Capt Ken]

Re: Lost spark for no known reason late 70's Mariner (50HP)

With the sparkplugs out, disconnect the black wire with yellow tracer from the CDI, spin the engine and see if you have spark then. If not, its probably the stator on that engine. If it sparks, you either have either a bad mercury switch on the side of the engine or grounded key switch.

 

[ba_50]

Re: Lost spark for no known reason late 70's Mariner (50HP)

I disconnected the yellow/black wire on the side of the motor electrical block and no spark.