Lost sparks

Hello and thanks for this great forum!<br /><br />The engine is a 25hp 2-cylinder 2-stoke Evinrude outboard from the early eighties. <br /><br />The problem is quite simple: No spark on either plug. Only that I don't really know how to start trobleshooting. I am not even sure I understand the function of this particular ignition system enough to start pinpointing the problem.<br /><br />The ignition as I see it: <br /><br />The flywheel has two magnets on its perimeter 180deg apart. Under the flywheel is one coil that has two wires, one combination of two coils has three wires and one white object that has a vertical strip of metal has two wires.<br /><br />The set of three wires go to a socket on the engine cowling. The other 2 + 2 wires go to another black well insulated object<br />(coil?) and from there one orange wire to #1 hi-volt coil, the other orange wire to #2 hi-volt coil and a black wire though the kill switch to the frame/ground.<br /><br />When I measured voltage between the wires coming from under the flywheel and frame all readings were zero. The black coil under the flywheel gave about 540ohms and the white object with the metal strip gave 37ohms. The comb. of two coils gave 0 ohms. I've tested the continuity of all related wires and they seem to be ok. <br /><br />I have not yet tested the continuity of the plug hats and hi-volt wires.<br /><br />I would be very very greatful on any advice and tips for this problem. I have a feeling that it can't be anything too complex but I just need to know what is what and what kind of readings should I get from different components.<br /><br />Thanks already!

Re: Lost sparks

first, make sure the kill switch is not the culprit, it could still be grounded. the black insulated thing you're describing sounds like the powerpack. describe the wire colors that you tested. both plugs not firing could be the powerpack or sensor, charge coil, or a damaged wire grounding out<br /><br />can you give us model # also, that would help some. <br />oh and welcome to the forum!

Re: Lost sparks

Thanks a lot for the response! <br /><br />I will go and check out the model #. It must be somewhere on the engine. I will also doublecheck the kill switch. <br /><br />

Re: Lost sparks

check on the transom bracket, mine's on port side, little metal plate riveted on

Re: Lost sparks

your unit runs from a magneto. On your stop push button switch you have two leads. One goes to engine ground the other is to a connector. Disconnect the connector and see if you get spark.<br />If so the stop switch is bad.<br /><br />Under the flywheel is your trigger sensing coil and the mag charging coil.<br /><br />The black cylinder like componet is you powerpack and then you have two high tension coils.

Re: Lost sparks

Ok, I checked the serial # and it is 258B62CB15952. I couldn't find any model number.<br /><br />I re-checked the kill switch and it was fine, no ground leaks. <br /><br />The sensor coil resistance measured between the white wire with a black stripe and the black wire with a white stripe was 37 ohms. The sensor output voltage between the same wires just barely reached 0,3 VAC while cranking the engine. No leaks to the ground or to other coils.<br />The resistance seemed ok but the weak voltage?<br /><br />The charge coil gave 542 ohms between brown wire and brown wire with yellow stripe but the output was only 79 VAC. Shouldn't it be much higher? There were no leaks on the charge coil.<br /><br />Since the charge coil output voltage was so weak we assummed that the problem is either in the charge coil or weak flywheel magnets? We didn't test the powerpack since we weren't sure about the charge coil and flywheel. Can a magnet just die out?<br /><br /> http://us.share.geocities.com/bstruyf2000/ignition.pdf <br /><br />I was using the above link as a guide and reference. Thank you to the provider! I didn't quite understand the meaning of jumping the ign. coil wires and leaving the ground wire out while testing the powerpack output.<br /><br />What do you suggest could be the cause of the problem? Thanks a great deal for helping out.

Re: Lost sparks

your model is a 1978 25hp evinrude<br /><br /> http://www.ishopmarine.com/ishop/js...325~M0011363~M0011365~C0148080&pCode=C0146648 <br /><br />according to CDI your trigger should have .5 volts<br /><br />check their electronic troubleshooting guide. pdf at the bottom of the link page <br /><br /> http://rapair.com/Default.aspx?tabid=90

Re: Lost sparks

Problem solved! The powerpack was changed and now the ignition and engine work fine. We were quite doubtful about the problem being in the charge coil or flywheel since they were giving reasonable readings (hopefuly).<br /><br />This forum has been very helpful and thank you mikeyzx2, Blueclaw and all other contributors.<br /><br />Cheers!