'77 888 no start/no fire

[racinrc14]

Finished up the installation of rebuilt 302. Hooked everything up, cranked it over and no start. Carb is getting fuel, plugs are not getting spark. Looked my manual over and the instructions are vague regarding troubleshooting the ignition and I don't have the "magneto analyzer" called out in the manual. I checked everything I could with a volt/ohm meter. The resistance wire to the coil checks out ok. I have 12v at the high tension terminal with the key 'on'. I also have 12v at the dist. end of the coil high tension wire. I have removed the points, filed them, and re-installed them with .019 gap. I'm not sure what to check next, any suggestions?

 

[racinrc14]

Re: '77 888 no start/no fire

How do I check those and what should the readings be?

 

[racinrc14]

Re: '77 888 no start/no fire

Ok, bought the tester (our local O'Reilly auto parts had them in stock, quite a bit more than the one online, but I have it in my hands for testing). I hooked everything up as per the instructions, green light, no spark. So off to get a new coil. Hooked it all up and again, green light, no spark. I moved the spark tester from 30Kv to 10Kv and observed a weak, yellow-orange spark. Is there something I'm not doing right? Is it likely that a brand new coil is bad? It is more likely I'm missing something, I think.

 

[racinrc14]

Re: '77 888 no start/no fire

Using the instructions included with the tester, I checked both coils on the bench and both produced bright blue sparks across the 30Kv gap. Why don't they check out in the boat? What am I missing.

 

[jimbo3123]

Re: '77 888 no start/no fire

Are you sure that your points are aligned and in good shape?

You could try "Hot Wiring" the coil (bypassing the key switch and stock wiring) to take that out of the equation.

Next I would try replacing (or temporarily bypassing) the little wire from the points to the coil. I would also replace the condenser while I was at it.

 

[racinrc14]

Re: '77 888 no start/no fire

I isolated the distributor and points/condenser from the tester by removing the leads from the (-) post on the coil before testing (as per instruction included with tester). Bench checking both coils with the tester produced bright blue sparks, so I think the coil (both of them) is good. But with the two wires on the (+) terminal connected and none on the (-) connected, the tester couldn't get either coil to produce spark. The two wires on the (+) side are power and ballast, and the two on the (-) are primary to dist. and brown wire to shift interrupt switch. I 'jiggled' the shifter to see if the interrupt function was doing anything funky, but didn't seem to have any affect on things.

 

[racinrc14]

Re: '77 888 no start/no fire

This might be a stupid question, but should the coil be grounded to the engine? Both of my coils are painted, with no bare metal to contact the mounting strap. Could this be causing issues?

 

[racinrc14]

Re: '77 888 no start/no fire

I'll disconnect and clean all the connections this evening after work. I did assume that since it 'ran' before that the connections should still be fine.

 

[gadget73]

Re: '77 888 no start/no fire

Use a test light or a voltmeter to verify you have power from engine ground to the + terminal with the key in the run position. Verify same when the engine is cranking. If the light dims severely while cranking, check to be sure the power wire is good. Thats actually a ballast bypass wire. If no power in run, check the other side of the ballast resistor. If you have power at one side but not the other, the resistor has failed.

I'd also unhook that shift interruptor for troubleshooting purposes. The motor will run fine without it, but if its shorted somehow it will kill the spark.

Last question, are your points in good condition and properly gapped? Has the condensor been replaced (usually done with the points) ? To take a guess, point gap is probably around .016, and it must be gapped on the high point of one of the lobes on the breaker point cam. Something else, do the points open and close fully? I've seen worn out cams, and worn out points that were so run down that they simply didn't operate properly. 95% of the time its going to be the phenolic on the points that fails, but I have seen one worn out metal points cam. Not a clue how it happened, but it happened.