89 OMC 5.0L Ford - no spark

[Travis71]

Boat has been running great with no problems whatsoever. Got it in the water, idled away from dock past no-wake sign and gave it full throttle and it died. Now it will not start and I am not getting a spark. I am completely new to working with points ignition so I read through the points system troubleshooting guide and I am getting good voltage at the coil: 5.2V with key on, 10.5V when cranking. Voltage reading at battery posts is 12.88V so battery appears to be charged sufficiently.

I moved to the distributor. The points, condenser, rotor, and cap were replaced recently in order to get this boat running in the first place after I bought it. I checked points gap and it was too narrow so I re-set that with a feeler gauge, .016" according to manual. I cranked it with the cap off and I can see arcing at the points as they open and close so they appear to be working properly. I am also seeing some arcing where the contact set fits over the post on the distributor plate. So I read this in the sticky guide:

"- If the points appear to be operating correctly, verify there are no grounding issues with the points or condenser"​

​

Please forgive me if this is a stupid question, but is the arcing to the distributor plate a grounding issue?

 

[Scott Danforth]

there are guides in teh stickies on points type ignition

first, file your points
then re-gap your points
verify your dwell is between 37 and 39 degrees
then put your cap on and set timing

 

[Bondo]

I am also seeing some arcing where the contact set fits over the post on the distributor plate. So I read this in the sticky guide:
"- If the points appear to be operating correctly, verify there are no grounding issues with the points or condenser"

Ayuh,...... It sounds like the anchored 1/2 of the points is hunting for a ground,......

Jumper the distributor body to a known good solid ground, 'n see if anything changes,.....

Probably wouldn't hurt to clean to shiny metal Clean, both battery cables, on both ends of the cables,......

 

[Travis71]

Ayuh,...... It sounds like the anchored 1/2 of the points is hunting for a ground,......

Jumper the distributor body to a known good solid ground, 'n see if anything changes,.....

Probably wouldn't hurt to clean to shiny metal Clean, both battery cables, on both ends of the cables,......

Did both of the above.

I had my coil checked by a mechanic I know and he said it is good. He even gave me a mercruiser coil he had lying around that he knew for a fact was good that he said was "hotter" - whatever that means. I have checked the mercruiser coil he gave to me according to the sticky instructions:
continuity between two posts - check
resistance between posts - .8 ohms
resistance between post and tower - 11,200 ohms

The original motorcraft coil checked also:
continuity between posts - check
resistance between posts - 1.6 ohms (a little higher than spec)
resistance between post and tower - 8,580

So, a couple of things I am uncertain of:
1. when I check continuity between post and tower on both of these coils I get no reading at all, no tone. The sticky instructions say I should get continuity here, but my mechanic checked out my coil and said it was good...does he not know what he is doing?

2. Back at the boat I have everything connected with a spark tester from coil tower to ground on engine block. I get a little orange spark when I initially start cranking the starter and again when I let off, but nothing at all while cranking.

 

[Travis71]

I started re-checking voltage at coil to make sure nothing had changed. I also was checking voltage at the wire connections inside the distributor body just to make sure there wasn't a problem with the wire from distributor to coil. Out of curiosity I started checking elsewhere and found that the plate assembly and the entire distributor body was measuring the same voltage as the coil with key on and while cranking.

I don't understand these systems very well at all, but this doesn't seem right to me...is it?

 

[Travis71]

UPDATE...

So what I discovered is that the moving arm on the contact points was shorting against the bracket that mounts to the distributor plate. It was sliding down the insulated shaft so that the two metal pieces were touching. Once I fixed that problem everything is working fine again.

Points gap and dwell angle are spot on, so now I need to check the timing...always a new adventure!