No spark plug spark... 170 MC , 1985 Sea Ray

[Scott Danforth]

Does this boat use a 6V coil and ballast resistor? It sounds like it might be low voltage at the coil when cranking. Try running a jumper wire from the plus side of the coil directly to the battery and see what happens.

no, the boat uses a 1.5 ohm coil requiring a balast resistor for running and gets full 12 volts when cranking via the I/R terminal on the starter. that is the way the boat is wired.

 

[glennj3]

I am now looking for some kind of short, maybe the tachometer?

 

[glennj3]

Does this boat use a 6V coil and ballast resistor? It sounds like it might be low voltage at the coil when cranking. Try running a jumper wire from the plus side of the coil directly to the battery and see what happens.

It’s 12 volt, regular point & condenser. I’ll try that.

 

[glennj3]

I am now looking for some kind of short, maybe the tachometer?

!
When I connected the battery hit the wire to the pos coil I saw a spark which I thought was odd. I went ahead & cranked her over and...... she fired up!
Wow that is something, thank you so much!
Now I suppose you can tell me what to do next?
I had # 2 / 12 volt batteries in the boat. I normally crank her with both so that shouldn’t have anything to do with it...

 

[Scott Danforth]

you have a bad wire to the I/R terminal on your starter. start with the factory service manual and follow the wiring schematics.

 

[isaacs]

!
When I connected the battery hit the wire to the pos coil I saw a spark which I thought was odd. I went ahead & cranked her over and...... she fired up!
Wow that is something, thank you so much!
Now I suppose you can tell me what to do next?
I had # 2 / 12 volt batteries in the boat. I normally crank her with both so that shouldn’t have anything to do with it...

The spark would be normal, and you probably noticed that the engine wouldn't stop 'till you removed the hot wire jumper. I can't tell you exactly what wire to look for, I'm not a mechanic. As has been mentioned, the schematic will be a good place to start (no pun intended). You're looking for something that gives the coil full voltage from the battery when the starter is engaged. It will be bypassing some sort of resistor that normally keeps the coil running at less than 12V. The purpose of all this is to negate the effect of the starter drawing down the battery voltage during cranking. I'm thinking that if you kept the coil at a full 12V all the time it would burn out or possibly damage the points. Glad you found the problem!

 

[glennj3]

The spark would be normal, and you probably noticed that the engine wouldn't stop 'till you removed the hot wire jumper. I can't tell you exactly what wire to look for, I'm not a mechanic. As has been mentioned, the schematic will be a good place to start (no pun intended). You're looking for something that gives the coil full voltage from the battery when the starter is engaged. It will be bypassing some sort of resistor that normally keeps the coil running at less than 12V. The purpose of all this is to negate the effect of the starter drawing down the battery voltage during cranking. I'm thinking that if you kept the coil at a full 12V all the time it would burn out or possibly damage the points. Glad you found the problem!

Thank you, I’ll work on it!

 

[glennj3]

you have a bad wire to the I/R terminal on your starter. start with the factory service manual and follow the wiring schematics.

I’m not good with schematics but I’ll try to find someone that can. Thanks!

 

[glennj3]

I believe this is for my engine. Possibly someone can assist me ?

 

[Scott Danforth]

yep, that is it. follow the wire from the R terminal (R is for relay, sometimes its call I for ignition) that is your feed to the coil + for cranking.

now, start at the coil + on the motor, follow that wire to your starter and fix what is broken/not tight/corroded

 

[glennj3]

yep, that is it. follow the wire from the R terminal (R is for relay, sometimes its call I for ignition) that is your feed to the coil + for cranking.

now, start at the coil + on the motor, follow that wire to your starter and fix what is broken/not tight/corroded

yep, that is it. follow the wire from the R terminal (R is for relay, sometimes its call I for ignition) that is your feed to the coil + for cranking.

now, start at the coil + on the motor, follow that wire to your starter and fix what is broken/not tight/corroded

That sounds simple enough. Sometimes it may be better to run a new wire & just remove that old wire due to wires wrapped together and hidden behind the engine?
By the way, with the jumper wire on and it fired up, it did turn off when I switched the ignition key off, I think. I didn’t have water to it and did not want it to run.
Thanks for yours & everyone’s help with this!

 

[Scott Danforth]

change your impeller. running for just a few seconds without water will toast an impeller

 

[glennj3]

Happy

change your impeller. running for just a few seconds without water will toast an impeller

No it only fired over. The schematic shows only one wire going to the R on the starter, so that would make it difficult to have a short in that wire? . My coil has 2 wires on the + side. Could the short be in the ignition switch or tachometer?

 

[Scott Danforth]

one wire on the + side of the coil goes to the R terminal. this is the source for voltage ONLY during cranking. this is the tan wire called out on the schematic

the other wire on the + side of the coil is connected to the resistance wire in the harness, and goes back to the key switch. this is the white wire called out on the schematic. this wire provides about 9 volts to the coil when running so you dont burn your points out

the above is standard points ignition (other than the non-standard wiring colors)

the - side of the coil has 3 wires. one is your tach. this is a brown wire in your schematic. the other is the shift interupt swtich, another brown wire and the wire from the points themselves which would be black.

if your lower shift cable is stretched, and your shift interrupt switch is not set properly, it will "kill" your ignition by grounding out the ignition.

you can test that by disconnecting the brown wire from the shift interrupt switch. Just dont try to run like that, you wont get the boat out of gear

 

[glennj3]

I removed one wire from the interrupt switch, not sure which one, but that did not help. It moved like it should.
When it warms up a little more outside I’ll check some more things. Like the tachometer and ignition switch.

 

[glennj3]

I removed one wire from the interrupt swnot sure which one, but that did not help. It moved like it should.
When it warms up a little more outside I’ll check some more things. Like the tachometer and ignition switch.

Picture of my coil and of the solenoid at the starter. I have continuity from the + coil to the red wires on the solenoid at the starter.
The yellow red wire reads 2.8 ohms on my meter from the + coil.

 

[glennj3]

So after looking for I don’t know what, I cleaned the ignition switch & wires.
I used a jumper wire from the 12 volt battery to the + terminal on the coil and cranked up & ran the engine on a water hose. I removed the 12 volt jumper wire soon as it cranked. It ran until it was warmed up very well maybe 10 to 15 minutes.
It then stopped running. Now no spark again with or without the jumper wire.
Looked like 9 volts on the + coil terminal with the ignition switch on.
My mind just does not wrap around all of this.
If you still want to advise me please do!

 

[Scott Danforth]

9 volts is standard with the ballast wire. your issue is somewhere between the R terminal to the coil +

 

[Scott06]

So after looking for I don’t know what, I cleaned the ignition switch & wires.
I used a jumper wire from the 12 volt battery to the + terminal on the coil and cranked up & ran the engine on a water hose. I removed the 12 volt jumper wire soon as it cranked. It ran until it was warmed up very well maybe 10 to 15 minutes.
It then stopped running. Now no spark again with or without the jumper wire.
Looked like 9 volts on the + coil terminal with the ignition switch on.
My mind just does not wrap around all of this.
If you still want to advise me please do!

When this happens take the coil wire off the distributor cap ground it and see if you get a spark while cranking. It’s possible your loosing spark in the cap and rotor

 

[isaacs]

9 volts is standard with the ballast wire. your issue is somewhere between the R terminal to the coil +

But now he says he has no spark with or without the jumper cable. That jumper would bypass any problem from the R terminal, wouldn't it? I'm thinking he may have multiple issues. Unless possibly the jumper was not making good contact this time. Are we sure there is 12V on the coil terminal itself with the jumper in place, not just on one of the wire terminals.