orange spark when running? is that normal?

[jfrey8899]

140 mercruiser from 1971 with two barrell carb. Runs good at idle and will open up all the way. Buy there is a slight un rythmic miss. Pulled off a spark plug boot and put another spark plug in it and started motor. Did this on all 4 plugs. Looks like an orange spark to me. Even after a new coil. Plugs wires rotor cap condensor and points. Still orange spark and slight miss. What am I missing. Is there a quick way to diagnose this. I havr multi meter just don't know what to test for.

 

[Alpheus]

Re: orange spark when running? is that normal?

Check the voltage at the coil when engine is running...

 

[jfrey8899]

Re: orange spark when running? is that normal?

Where do I put my tester leads. What should voltage be. I'm still waitin on my manual

 

[Bondo]

Re: orange spark when running? is that normal?

Buy there is a slight un rythmic miss.

Ayuh,.... How much Crud/ Corrosion is there in the Carb,..??

 

[jfrey8899]

Re: orange spark when running? is that normal?

Carb. Rebuilt. Went well. Fuel lines and filters new. Starts right up.

 

[jfrey8899]

Re: orange spark when running? is that normal?

Did compression check. About 140 across the board. And did fuel pump test with compound meter. 4 Psi then slowly builds to 5. So that checks out too I think

 

[jfrey8899]

Re: orange spark when running? is that normal?

still got orange spark

 

[littlebookworm]

Re: orange spark when running? is that normal?

1971 engine uses points and a condensor. You didn't say anything about changing them. I recommend you do so. Make sure you put a drop (match head size) of grease on the rub bar. I'd also suggest you double check your coil. I'm not sure you've got the right one.And finally, check if you have a resistor or resistor wire in the ignition circuit; it may be bad. Those are the three causes of weak spark we used to find on car engines. Rules are basically the same for marine engines. let us know what you find. Hy

 

[jtmarten]

Re: orange spark when running? is that normal?

Sounds like a weak coil, due to bad ground, corroded + feed, etc.

 

[jfrey8899]

Re: orange spark when running? is that normal?

New coil and points and condensor. Even got a newer better coil by msd ignition and still the same thing. Orange spark. Guess next avenue would be that resistor wire huh

 

[Alpheus]

Re: orange spark when running? is that normal?

Put the red lead on the + side of coil and the black lead on the - side with the knob turned to V DC 2-20 V range or auto range (depending on what meter you have) while the engine is running and with it off and ignition turned on. What do you get???

You can download the manual for free right here...

http://www.4shared.com/document/_nhtFGoc/Mercruiser_Service_Manual_01.html

 

[Alpheus]

Re: orange spark when running? is that normal?

Put the red lead on the + side of coil and the black lead on the - side while the engine is running and with it off and ignition turned on. What do you get???

You can download the manual for free right here...

http://www.4shared.com/document/_nhtFGoc/Mercruiser_Service_Manual_01.html

Here is a small video to help you learn your multimeter.

http://www.youtube.com/watch?v=KzjMIcER4EU

Learn as much as you can about it. It is your best friend in electrical troubleshooting...

 

[Aloysius]

Re: orange spark when running? is that normal?

You DO have the coil polarity correct..negative to the distributor??

 

[jfrey8899]

Re: orange spark when running? is that normal?

Yes negative to dist hooked up. Now I also have a new battery buy not new alternator. However for the last month I have not run it long enough to kill battery I don't think. Maybe 40 or 50 starts while in driveway and combined maybe hour on water. Could a bad alternator be masked by a good battery. Just a thought. Don't think so but wouldn't put uy past this boat. What are signs of a bad alternator. Or am I reaching on this one

 

[Alpheus]

Re: orange spark when running? is that normal?

Again use your volt meter. put it on the battery while engine is running and look for 14 + volts...

 

[jfrey8899]

Re: orange spark when running? is that normal?

Well. Verdict is in. Turns out to almost definatly be electrical. Unwrapped all tape of harness wires and found the red alternator wire had an exposed piece under the tape. And under dash especially under key all wires appear to be cracked in numerous spots. Also brown wire from alt to coil cracked in numerous spots under tape. Well that says it. Total rewire. My question. Do I need to do each wire one at a time or can I just buy harness with all wires already in it. What's the simplest way to go about this. Any help would be greatly appreciated. Thanks for all help so far.

 

[Alpheus]

Re: orange spark when running? is that normal?

I dont think there is a harness that is ready made for your boat/engine. I would read the wiring diagram, get yourself some new wire and R&R one and a time. You can either solder new wires in place and use heat shrink to cover or get some marine grade crimp splices...

PS

Use as many different color wires as you can. If you redo the hole thing with just one or two color wire its gonna be a nightmare unless you label them...

Read this:

http://www.pbase.com/mainecruising/wire_termination

 

[sethjon]

Re: orange spark when running? is that normal?

1971 engine uses points and a condensor. You didn't say anything about changing them. I recommend you do so. Make sure you put a drop (match head size) of grease on the rub bar. I'd also suggest you double check your coil. I'm not sure you've got the right one.And finally, check if you have a resistor or resistor wire in the ignition circuit; it may be bad. Those are the three causes of weak spark we used to find on car engines. Rules are basically the same for marine engines. let us know what you find. Hy

He mentioned that almost at the onset. Read a bit more carefully.

 

[sethjon]

Re: orange spark when running? is that normal?

New coil and points and condensor. Even got a newer better coil by msd ignition and still the same thing. Orange spark. Guess next avenue would be that resistor wire huh

But are the connections good?

 

[LAC_STS]

Re: orange spark when running? is that normal?

Before you go rewiring everything check and see if it's you deistic wire/ballast resistor going to the coil. I was chasing down problems for a while. It would run great all the way up to 3500 RPMs. Then it would start missing.

I ended up running a 12V wire to the coil while it was messing up and it stopped right away. I don't know if you wanna do this as you will have to replace your points and condensor afterwards and maybe our coil.

But if ou look up the ballast resistors both MSD and Accell make them and you can get the Accell one at NAPA for about $10. Just wire a new wire from your alt to the ballast resistor then to the + of the coil. Make sure to remove the old resistor wire from the coil.

I think the Accell ballast resistor part number is 700.