OMC 351 King Cobra

[darkarcher]

I am not giving up on this.

I am going to post a few pictures.

My battery is a little low but this is the same reading I get from each of the connecting wires when the key is in the off position.

When I turn the key to the run position I get the same reading on all the post but this one

The flash hid the reading but it is 0.2

Is this the correct reading?

I want to test the coil output. I have tested the coil and it seems to be withing tolerance levels. I am going to pull it again tomorrow afternoon and test again just to make sure.

 

[mkast]

Re: OMC 351 King Cobra

I'm not familiar with your installation, but if you are testing a coil, why are you checking voltage at a solenoid?

 

[bruceb58]

Re: OMC 351 King Cobra

You are probing at the starter assist solenoid. Are you haveing problems with your starter.

You are also probing in the first picture between the input and the output of a solenoid...why?...unless you are measuring the voltage drop of a solenoid while trying to start.

Not even sure what you measuring to in the second picture.

Like Mkast said before, why aren't you looking at the coil voltage?

 

[Gary H NC]

Re: OMC 351 King Cobra

So what is the problem? No start?

 

[darkarcher]

Re: OMC 351 King Cobra

Problem is no start.

I was testing the voltage drop during cranking. When I crank the voltage drop is dramatic.

I have tested the resistance on the coil but I am not clear on how to test the correct voltage at the coil.

I can post some more pictures of my setup this afternoon but the coil is mounted on the port side in a rectangular black box.

 

[Gary H NC]

Re: OMC 351 King Cobra

So the engine turns over but will not start?
Have you checked for spark at the plugs and to see if its getting fuel to the carb?

 

[bruceb58]

Re: OMC 351 King Cobra

I can post some more pictures of my setup this afternoon but the coil is mounted on the port side in a rectangular black box.

So...why then are you probing the assist solenoid on the starboard side of the engine?

 

[darkarcher]

Re: OMC 351 King Cobra

Like I said I was showing the voltage drop since the top lug on the slenoid goes directly to the coil. It may make no difference at all but I don't know that. How would you suggest I test the coil?

I have pulled a spark plug wire, put a spark plug in it, grounded it to the engine and cranked the engine. Slight yellow spark intermittent.

I have loosened the fuel line to the carb and cranked the engine and fuel comes out.

I have tested the resistance on the coil and as soon as I get home I am going to test it again to make sure but it checked fine a couple of weeks ago.

I don't know how to test to see if the coil is getting enough voltage or if it is putting out enough to make ample spark

 

[bruceb58]

Re: OMC 351 King Cobra

You need to test at the coil itself. Probing the assist solenoid is going to give you the voltage drop at the assist solenoid.The lead to it comes pretty much directly from the battery. The lead that goes to the coil goes from the battery, through a circuit breaker, up to the ignition switch, back to the engine, through another connector... see where I am getting at? Measuring voltage drops needs to be done as close to the device as possible. In this case you need to get right at your coil.

 

[Don S]

Re: OMC 351 King Cobra

I'm not sure what that solenoid does or why it's there. The readings are normal by your discription of where the power is, but it makes no sense how the relay is wired.
It's something someone stuck on there, but they wired it wrong.

You also say you have a no start problem, does the engine turn over and just not start or when you turn the the start position nothing happens?

What is the FULL model number of your engine?
Something is all messed up.

 

[darkarcher]

Re: OMC 351 King Cobra

I tested the coil with my test light. Here is how

When I crank like this nice blue spark shoots from the probe to the ground.

This tells me that the coil is putting out spark. I just don't know how to tell if it is enough.

I then took off a sparkplug wire and did the same test like this

Plug # 1 no spark

Plug # 2 no spark

Plug # 3 no spark

Plug # 4 no spark

Plug # 5 no spark

Plug # 6 no spark

Plug # 7 slight yellow spark

Plug # 8 no spark no light

1 - 6 did light the test light up during sparking but wouldn't arc even the slightest bit, 8 wouldn't even light the light


Does this mean replace distributor?

 

[darkarcher]

Re: OMC 351 King Cobra

Don,

Everything on this is stock. 584DPPJVB. 1993 Spitfire.

EDIT

The above statement should have been:

As far as I know everything on this engine is stock.

End EDIT



This is a close up of the solenoid. It appears where it seems it should

A little bit further out shot.

 

[Don S]

Re: OMC 351 King Cobra

From what I see and read here, you are basically doiing non tests. They are meaningless.
Looks like you are stabbing the plug wires with a test light. If so, the wire is then junk. Along with the bulb in the test light. They won't handle 30K volts.
Get the proper tools, proper manual, and learn how to do the tests. Then you will stand a chance of finding out your problem.

You are trying to test coils and starter systems in ways I have never seen before.

 

[JustJason]

Re: OMC 351 King Cobra

+ 1 to don s. You have no idea what you are doing....

This is a typical voltage drop test.

http://www.fluke.com/application_notes/automotive/circuit.asp?AGID=1&SID=103

 

[darkarcher]

Re: OMC 351 King Cobra

I have the manual. What is the correct tool to test the spark?

I was not stabbing the wire with the test light I was using the aligator clip to connect to the wire.

The manual I have gives no details on testing the spark.

Each of you that has said that I don't know what I am doing is correct but I am trying to diagnose the issue by following suggestions here and the manual and other suggestions.

I would gladly try the right test and not the wrong one.

 

[JustJason]

Re: OMC 351 King Cobra

I have the manual. What is the correct tool to test the spark

A spark board... This is what I use...

http://www.stevensinstrument.com/spark_checkers.htm

I use a pair of the 4 wire ones.

Sooo... what's your issue???? is this a continuation of an old thread? Because in just reading this thread I have no idea what your trying to do... i only know that whatever your doing is wrong.

If your doing a voltage drop test... remember you need to "BE CRANKING" while your taking your readings.

 

[darkarcher]

Re: OMC 351 King Cobra

Plenty of crank and no start.

Clean fuel

I think that I don't have spark at the sparkplugs but I am not sure and I am trying to confirm or rule that out.

Got this from another site.

I couldn't expose the inside of the wires so I connected the alligator clip and used the test light

I am not an expert on the 420, but generally speaking here is how I do it:
1) pull the wire from the coil to the distributer and lay the end of the wire about a half inch from the metal of the engine. Crank the engine. You should see a hot blue color spark jump at least a half inch with a snap. That proves the coil and wire to distributer is ok.
2) Wires usually measure about 7K ohms each. If they measure 20K, there is a problem.
3) Reinsert the wire from coil into distributopr and pull spark wires one by one and repeat the initial test. Lay each wire one by one a half inch from engine block and crank engine. Observe that spark is hot, blue color and with snap. If all wires show weak spark you have bad distributor cap or rotor, or bad wires.

 

[IVAZ]

Re: OMC 351 King Cobra

Is your cap and rotor in good shape?

 

[darkarcher]

Re: OMC 351 King Cobra

The cap does not appear to be broken / cracked / damaged. However I don't seem to be getting spark. I am going to try and find a real spark tester today to actually check the spark.

I took some pictures of my cap and button

They don't have anything that jumps out at me but as I have learned on this forum I really don't know what to look for. I am trying to learn though

How could I test the cap and rotor?


again... any and all help is appreciated.

thanks

 

[bruceb58]

Re: OMC 351 King Cobra

Your cap needs to be perfectly clean and dry for it to work properly. I would suggest buying a new cap and rotor and giving it a try.