Mercruiser 3litre No Spark

[viper1]

http://forums.iboats.com/forum/engi...rives/9920412-mercruiser-3-0-no-spark-at-coil

Just seen this post^^. I'm having same problem on an 87 3.oL except i have no points. Changed coil ,coil wire ,plugs cap and rotor. Juice to the coil but no spark from coil. Im wondering if it could be the electronic unit in distributer. If so is there a way to test it?

 

[achris]

Viper,

I have separated your post off as it's own new thread.

As you say you replaced the coil, I'll assume it looks like a normal coil, with just the one lead coming out of it. (2 different systems used on 3 litre engines, the other has 4 HT leads coming from what looks like a coil).

You appear to have the Delco EST system. As long as you have verified that you have a good power and ground, and the new coil is the right one, then yes, the module in the distributor appears to be faulty.

One more question... Is this a standard Mercruiser supplied ignition system? It's not a points system that someone has just replaced the points in the distributor with an electronics module is it?

Chris.......

 

[viper1]

I really dont know It is a yellow colored module in the distributer. And yes coil is a typical coil used with the points system. With one coil wire. Is there a way to test this module with a ohm volt meter to see if its working?

 

[viper1]

Yes plugs, cap, rotor is new. Also the coil and coil wire. 12+v at coil. I do have one thing to check. After laying last night and thinking. I do remember that yellow module, but i didn't see no trigger. Sorry Its been a long time since I worked as an auto mechanic. So the names slip my mind. But the early systems used a pickup sensor and a piece on the distributer to set off the pulses. I didnt see that piece on the distributor shaft. But the rotor that came with the cap is different. the working parts are the same. But the old rotor was round and this one is the typical one. They surely wouldn't use a rotor as the trigger....or would they.
Also I remember we could check the out put by hooking up a ohm meter and cranking engine over. But cant remember the correct hook up. Hate to put more money into it with no results. Bought this boat as key ready during the winter. When we couldnt start it. Now this and also after checking bellows out Im looking at a whole stern redo. Bellows was shot. So soon as the motor is done Im ripping out the out drive bellows, gimble and all. LOL!

 

[achris]

OK, sounds like someone has converted from points to electronic. Pull the module out of the distributor and see if you can find a name on it. If it is what I think it is, then yes, you should have a trigger on the shaft. It may be that the trigger is lost, in which case, pull the module out and see if there is a name on it.

 

[viper1]

Well problem solved. I was given the wrong rotor. We new it looked different but its contacts was right and so was the location. But this electronic ignition uses the rotor for the trigger. How stupid. Now to get a rotor when i tune it. Ill need to contact mallory.

This is a close up. And what got me thinking. See no trigger point.
http://s1229.photobucket.com/user/vi...hhhz.jpg.html]

 

[viper1]

This is the old and the new rotor Old on the right.

This is the under side. Notice the router has a 4 section plastic fin that goes around the bottom. This is the trigger

So if you need to tune these up dont believe the parts man. That is not a radio interferance shield. LOL! And I will try to locate a new one now.