No Spark, but power to coil???
 

I am dead in the water right now. I was cruising and my engine (merc. 502 carbed) sputtered 2-3 times and quit. It felt like the carb was loading up and my plugs were fouled. At first I pulled the plugs because it seemed like they were fouled. My #7 plug was completely fried. I replaced all the plugs and did not fire at all. Pulled one plug and rolled engine over and no spark. Put test light on coil and I have power to coil. Put a used coil I had off another 502 and still no spark. Where do I go from here, and why did this plug burn like it did. All the rest of plugs were fouled but still in good shape.

Re: No Spark, but power to coil???
 

What kind of ignition?

Re: No Spark, but power to coil???
 

I had a plug do that from a lean condition on a blower motor. Bad octane.

Re: No Spark, but power to coil???
 

It is a MSD coil and distributor, both are only a couple months old.

Re: No Spark, but power to coil???
 

It is possible the coil to distributor wire is broken or bad.

How are you checking for spark? If you have or can borrow a working timing light it will help diagnose this, you can see if the distributor is feeding the plug wires with it.

Also, I am assuming you are running the stand alone MSD distributor, check to make sure it is still plugged in and properly grounded.

Bad plugs/wires/coils can wipe out the electrical pick-ups in distributors. They don't always do it, but it happens.

Re: No Spark, but power to coil???
 

I pulled a plug, touched it to the block while a buddy turned the engine over and no spark. I will check the dist and wire.

Re: No Spark, but power to coil???
 

check dist have some one crank mtr with cap off make sure rotor is turning you might of ate a dist gear,

take a test light to the - side of the coil attach other end to pos on batt crank mtr the test light should flash to show pulse to coil if not you have a bad pick up

Re: No Spark, but power to coil???
 

A bad MSD, unheard of!
BTW cranking an engine without the plugs hooked up, or grounded, can fry some ignitions.
Gary

Re: No Spark, but power to coil???
 

What kind of Champion plug is that?

It looks pretty mangled, is it a split fire? If so, I wouldn't use them in a boat. Use a race plug.

Re: No Spark, but power to coil???
 

If you are running MSD's ready-to-run distributor, it is probably a bad module which is not customer serviceable.
Send the distributor back to them and they will replace it with a 'reman' replacement for around $75.00. Be sure to send in the cap and rotor and they get replaced in the process. BTDT