Ignition system

[Kingmt01]

I thought I had everything working well in my new to me boat until I put it on the water today. Taking off she did miss a couple times but smoothed out & keep on going. The trim motor stopped working on me but I'm pretty sure I know why. After about 15 minutes she died on me & this googan had to bum a tow.

I don't trust my multimeter but I'm pretty sure the coil is dead. It says it requires a external resistor but I can't find a ballast anywhere on this boat.

It's a 84 Thunder Craft
3.0 OMC
OMC outdrive

Anyone have a clue where the resistor is?

 

[Kingmt01]

Got a new battery in my multimeter & the readings looked better. The coil tested good.

It's been a long time since I've had to work on a points ignition system.

 

[Scott Danforth]

your coil is not dead......its almost never never the coil. only 3 out of a million replaced coils are really bad. that makes is a 99.999997% probability its not the coil

the feed from the ignition to the coil is a resistor wire. available in a spool or by the foot from napa

on your new to you boat, you didnt do all the maintenance service. and on your '84 OMG, that means for the ignition alone, to file the points, rough gap the points to .018, verify 30 degrees on the dwell meter and set the timing.

you will need to do this every spring (takes about 5 minutes)

also on you new to you boat, you should pull the drive, replace the raw water pump, verify your vertical driveshaft splines are in good shape (they all fail). Make sure your ball gears are not worn, then pressure check the drive and re-fill all the fluids

what ever you do, dont damage the shift cable. that little wonder is $750

you will also want to check your stringers and transom.

 

[Kingmt01]

Points & condenser were new (as in not used). I cleaned & set them. It was running like a dream for about 30 minutes in the water. I had just turned to head back to the ramp & opened it up to overtake a boat pushing coal up the river. I'm so glad it died before a went in front of them instead of after. Definitely a no spark issue. I agree the coil is good after retesting it.

Any idea what the resistance should be on the wire?

 

[canuckboater]

I've been reading 2 ohms for my 120

 

[Scott Danforth]

I've been reading 2 ohms for my 120

your 120 what?

you do realize you're hijacking a thread?

 

[canuckboater]

OMC 120
Do you know what the resistance should be for his 3.0?....OMC

 

[Scott Danforth]

OMC 120
Do you know what the resistance should be for his 3.0?....OMC

Out of courtesy for the OP, you should start your own thread.

Regarding your motor, its never the coil, service your points

 

[canuckboater]

Scott
It was out of courtesy that I mentioned the resistance of the wire on my 120 OMC is 2 ohms as per factory spec....as I figured his was the same...Since then I've also learned that the 3.8L OMC has a resistance wire as well....and guess what it has a resistance of 2 ohms...
So I should start my own thread in trying to help the OP? Not sure how handy that would be for the OP
Perhaps you missed the part where the OP was asking for the resistance on that wire

 

[canuckboater]

Copied from another.....
Apparently from an OMC service manual #570605

"Resistor Wire

For Models: All

Special Tools Required: Ohmmeter

Test Procedure - Resistor Wire

Disconnect 20 gauge purple/red resistor wire from ignition coil positive (+) terminal. Disconnect purple lead at back of alternator. Connect ohmmeter between purple/red wire at coil and purple wire at alternator. Meter low ohms scale should read:

Resistance in Ohms............................ 2.0 plus/minus 0.5

If resistor wire fails test, do not shorten wire. Replace engine wiring harness."

 

[Scott Danforth]

its never the coil

since no-one sells harnesses for OMC, if the resistor portion of the harness is bad, just splice in a 15-18" section of resistor wire which is available at Napa or any of the real automotive parts stors (not Autozone, Advanced, or pep boys). no need to replace an entire harness for $8 worth of resistor wire and a $0.10 crimp connector.

the OP hasnt been back. the issue most likely is failure to lock the points down and they drifted close

 

[Kingmt01]

I had to go out of town then when I got back I've been dealing with legal crap & back issues.