520H No spark after sitting one week.

[lllBAMlll 1]

I have a 1996 520H.   I replaced the charging regulator about a month ago and has ran fine until this week.  I have replaced the relays also, but not with genuine replacment parts.  The wiring harness is a bit of a mess as someone has moved 2 of the fuses from the crap fuse holder.   I let it set for a week, and no spark!  turns over fine, one relay kicks in on run, another on start, cant tell about the third.  The coil doesnt show any physical damage, however the new regulator is already cracking a little.   oh, and the oil light is blinking.  seems odd that no spark after sitting,  even though everything else brakes after you turn it off.   Im not sure where to start?

[lllBAMlll 1]

I tested for a low oil pressure cut out by jumpering the + side of the coil to the plus side of the battery.   Cranked the engine over with the spark plug out and grounded, no spark, guess the low oil cutout is good.  Next test was to check the ignition module by using a volt meter.  I connected the + side of the volt meter to the - coil terminal (larger one) and grounded the other volt meter probe.  With the key in run, I rotated the flywheel and watched the volt meter jump from 12v to 1.5 volts which means the ignition module is good.  I tested the coil last with an ohms meter.  the top lugs on the coil produced a resistance of 3.60 ohms, however the the leads inside the spark wire holes produced no reading.  The book said it should be between 14,500-19,800 ohms and that if either were not in range to replace the coil.  Unless someone has anything to add, I guess im replacing the damn expensive coil!

[Theroundhousernr 589]

   Atleast you dont have to pull the flywheel off and change the module. What a pain in the dupa. I would change a coil any day over the module ,but on the plus side .You get to clean off them cooling fins when you do a module.

 

   Look into a 12 volt harley coil in the 3 to 5 ohm rating. Many have done this with success. Both harleys and Onan fire both plugs at the same time. Much cheaper than the Onan. I believe Martin may have a part number for you if my memory serves me correctly.

 

    Good luck

[312Hydro 474]

Do the mod with the Harley coil. Martin posted it here -

I followed Martin's post and even bought the same coil from the same eBay seller.http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&vxp=mtr&item=301252503367 He had the best price. I found that I could use the original wires by positioning the coil so both wires reached it. I did have to remove the front wire from it's clip to give it more slack to reach the new coil.  BTW here is a perfect opportunity to say THANK YOU MARTIN for sharing your solution. You saved me a lot of money!