No spark on any plugs on my 88 merc 115?

[wilson750]

I have been having problems all summer with this motor..Some days it would start right up, others it wouldnt start at all..It wouldnt get any spark!!! I have a new trigger in there,also a new stator..I have taken off the black & yellow wires and tried that also.. Still no spark.. I dont know what more to do.. Would a bad ground on the motor do it? Key switch? Thanks

 

[Laddies]

Re: No spark on any plugs on my 88 merc 115?

Start by removing the black/yellow wire from the switchboxes to see if the problem is with the engine or in the wiring harness' here's the test for the complete ign. system.

 

[wilson750]

Re: No spark on any plugs on my 88 merc 115?

Thanks Laddies, I took off the yellow/black wires off already..That didnt help..I will try disconnecting the yellow wires at the rectifier..The rectifier was replaced about 2 months ago though because it went and wouldnt allow the motor to turn over.. If there was a problem with the rectifier would it still allow the motor to turn over?

 

[wilson750]

Re: No spark on any plugs on my 88 merc 115?

Ok i went to the motor tonight.. I dont know what rectifier the above page is talking about..It says disconnect the yellow wires from it.. Im lost here.. This is driving me nuts because there is no spark..

 

[Laddies]

Re: No spark on any plugs on my 88 merc 115?

If you don't know what a rectifier is it's one of these, you relly need to get a manual and a DVA if you going to try repairing your own engine. I have repaired Mercurys since 1964 (45 years) and when I don't have spark on a engine, when I go to the engine I have a manual and DVA in hand.

 

[wilson750]

Re: No spark on any plugs on my 88 merc 115?

I have the manual.. I could not find any help in the manual.. I understand the rectifer.. I have power on it,The motor will turn over great, just no spark.. The yellow wire on it is from teh key switch, when it gives it powe the more will turn.. Soo that is working fine..

Laddies i wanna thank you for the time you are putting forth..I just wish i could figure this spark problem out..

 

[Laddies]

Re: No spark on any plugs on my 88 merc 115?

Then do the test 1 step at a time and do all of it it has never failed me.

 

[wilson750]

Re: No spark on any plugs on my 88 merc 115?

Thanks Laddies, I am also going to check the new stator.. I wanna make sure that it didnt take a crap already.. Its only a year old..

Thanks again

 

[arsenalpsu]

Re: No spark on any plugs on my 88 merc 115?

This is probably a stupid questions but will a bad rectifire cause an engine not to fire? I thought it would only cause the tack not to work and the batter not to charge?

 

[arsenalpsu]

Re: No spark on any plugs on my 88 merc 115?

any takers on this one?

 

[CharlieB]

Re: No spark on any plugs on my 88 merc 115?

Yes, a bad rectifier CAN affect spark, which is why one of the tests calls for you to disconnect the rectifier THEN retest spark.

One of the very first things I suggest you check is cranking speed, these ignitions have a MINIMUM cranking speed of 300 RPM. A weak battery, apoor cable connection, a weak starter, any can appear to be an ignition problem when actually it just isn't cranking fast enough to make the electricity necessary for the ignition to function.

Check battery voltage, charge if needed, clean BOTH ends of BOTH battery cables AND the short cable from the starter motor to the relay, then retest for spark.

 

[arsenalpsu]

Re: No spark on any plugs on my 88 merc 115?

I think i see what you're talking about, the rectifire altough it doesn't directly generat the spark, incrases the voltage when she's spinning which helps to get it started. Then of course it keep the system charged to help in future starts which is why it's included in this testing section...

Or something along those lines....

 

[wilson750]

Re: No spark on any plugs on my 88 merc 115?

I just wanted to give an update..I pulled the stator off and tested it..It was bad..So i ordered a new one and she fired right up..THanks for all the help.. This forum rocks!!!