Merc 470 No Spark

[Merc470]

Boat ran last year, took it out this year and no spark.

Voltage at coil is full battery voltage on both terminals, I know this is not right. I have not messed with any point ignition before.

I tried a different coil just because and had the same readings.

I have read some of the other posts and haven't gotten any new insight.

Where do I start?

Thanks, Ben

 

[Bt Doctur]

Re: Merc 470 No Spark

cleaning, checking,adjusting the points.
http://autorepair.about.com/cs/generalinfo/a/aa052502a_2.htm
http://www.boatfix.com/merc/Servmanl/13/13B4R2.PDF

 

[rodbolt]

Re: Merc 470 No Spark

if between the coil - and engine ground you have battery voltage check for open points or an open wire between the - term and the dist, also check the point ground plate.
your voltage readings indicate an open circuit between the - coil terminal and the block.

 

[Merc470]

Re: Merc 470 No Spark

I have the same voltage at "-" terminal on coil when points are both open and closed.

Full battery voltage, same as "+" terminal.

 

[Bt Doctur]

Re: Merc 470 No Spark

how did you determine the point contacts are actually making contact?
sometimes they oxidize and even closed there is no contact .run some sandpaper thru them .and post results

 

[Merc470]

Re: Merc 470 No Spark

I'll be danged.

I had wiped point contacts off when I had cap off but I didn't touch a file to them.

Just went out and touched a file to them, put cap back on and made sure all wires were connected and had instant fire.

Will change lower unit impeller tomorrow and see if that takes care of the cooling problem.

Then hit the lake.

Thanks so much, Ben

 

[Don S]

Re: Merc 470 No Spark

Put some new points in it. Filed points don't last very long.

 

[Banditz]

Re: Merc 470 No Spark

DONT run a file between them...it leaves fine granules of sand that will just make things worse. More than likely your just in need of a few cheap things to get you up and running. First, replace the point. Then replace the cap. Its the little black or silver round thing with a single wire hanging off. Its inside the cap. Once you do that you will maybe have $20. In the whole set up.hose things are needed maintaince anyway so doing them is not wastefull at all, if nothing else it ensures no failures out on the water. Or at least less likely. Take your points, and the cap down to the local auto store and match them to new ones.....Good luck and post up your findings!

 

[wire2]

Re: Merc 470 No Spark

.... Its the little black or silver round thing with a single wire hanging off. Its inside the cap....

Rotor.