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96 Mastercraft - Chevy 350 Engine

F

Former Marine

Member
My boat engine will crank but not fire. I have replaced all sparkplugs and have checked fuel lines and fuel filter. I have checked the kill switch and have tried to crank with throttle in reverse and in neutral.

I don't think engine is getting a spark? How do I trouble shoot?

Appreciate any advice

Colonel Mike Andrews USMC RET
 
Col:

You need to determine is you have spark. Use a spark tester or another spark plug. Pull the plug lead off the easiest one to access, insert the tester/plug, and ground its other end. When you crank the engine, you should see (and possibly hear) a nice blue arc across its gap.

For the fuel check, do you have a carburetor or fuel injection?
 
The boat has got electronic fuel ignition with carb throttle body. going outside to test for spark now. when i turn the ignition on I can hear the fuel pump come on.
 
Sir:

That is fuel injection, not ignition. Your setup is referred to a TBI - throttle body injection.

Hearing the fuel pump run for a couple seconds when the key is turned on is normal and a good thing (provided there is enough fuel in the tank).
 
Please don't call me Sir. Call me Mike. I Tested spark by unplugging plug wire and plugging into a spark tester and did not get any spark at all. tested two different plug wire and no spark.

Need help!
 
Ok Mike - no disrespect intended - just of by-product of being in certain environments.

No spark - ok, here's what I would suggest:

Repeat the spark test but use the coil lead, unplugged at the distributor. If that sparks, there is an issue with the cap or the rotor.

Next to check would be for B+, on the coil's + terminal, with the key on. If not there, check the ignition switch for B+, to the IGN terminal, with the key on. Since it cranks, B+ is at the key and the main breaker is intact. Another possibility would be an open (burnt out) ballast resistor if your coil requires it.

After that, you need to check the distributor internals. What to check depends upon the trigger used inside (points or a non-contact mechanism). Know what type of distributor it is helps sometimes, too.

Does this have a "computer" controlling the engine ?
 
Don't have points on this dist from what I can tell. spark tested the coil lead and din NOT get a spark. removed coil and took to auto parts 'OReilly' and they had something similar but did not come on a heavy duty mounting bracket to mount to engine block like mine. Where is best place to get this part? Since no spark do you agree that the coil is the bandit?

Thanks

Mike
 
Don't agree that the coil is bad.

Throwing parts at a problem isn't fast or cheap. Best to find out what isn't working and then fix it.

Most coil brackets can be reused, at least the stock ones.

Did you check for the B+ (12 volts DC) at the coil's + terminal, with the key on?

Does the coil has a ballast resistor close to it?
 
haven't ordered the coil yet?

What are you referring to, when you say B+ and Their is a circular brass plated object next to the coil and distributor that has a wire with a plug cover over it (is this the ballast resistor?) Looks like I need to break out ohm tester. Just let me know what B+ is and I will test it?

Thanks, I really appreciate your time and advice,

Mike
 
B+ is the 12 volts DC fed from the ignition switch, to the coil, when the key is turned ON.

Ballast resistors are used with a coil that requires them. The coil will have something like USE wiht EXTERNAL RESISTOR printed on it. used mostly with points systems but can appear on electronic trigger systems. The ballast resistor limits the current flow thru the ignition's primary circuit. they are known to burn out which means no spark from the coil.
 
Found the plug that plug into the coil is has an A and B on it and there is also another plug as well that plugs into the coil as well and one location to plug in a plug wire which in turn plugs into the distributor. Looks like my A/B+ Plug - plugs into the coil and then plugs into the distributor and I'm guessing other plug runs to ignition?

There's no writing on my coil at all just numbers. At the edge of the distributor and dist. cap there is a small brass bell shaped object that is screwed into the engine block and has a wire screwed on top of it with a rubber plug cover that pull over the wire and screw area and that wire leads into a main system of covered wires leading to the starter system. Is this a ballast resistor?
 
Sounds like you mmay have the DELCO EST ignition system. Do a www search and see if what you find matches what you have. Some people also label them Delco Voyager Marine Ignition.

They can be installed in a ECU controlled manner or in a stand alone mode.

As best as I can decipher from your description, your brass bell shaped item is probably the oil pressure sender. Colors of wires connected to things on the engine usually have significance.

If you have a digital camera, pictures of things would help immensely, especially if you can annotate the pic.

The purple wire, at the coil connector NOT going to the distributor, is where the B+ (= 12 VDC) is fed to the ignition, from the key switch.
 
did some back tracking once I found my volt/ohm tester. I unplugged coil wire from distributor and stuck red prong of tester in to the coil plug and place black prong of tester on ground point on engine. Turned ignition key on and got around 11.8 volts.
So doesn't that mean that I am getting spark all the way up to distributor cap? I have already replaced dist cap but have not replaced rotor? Your reccomendation?
 
Here are the photos:

35257_10150229921730693_736175692_13548933_2246919_n.jpg
 
Photo 1 is pic of distributor, can't get white cap off. Pulled up gently and would not come loose.

In pic 2 is that the ballast resistor where to two plugs plug into

Pic 3 is the coil

Any advice is appreciated.
 
Mako,

I replaced the rotor, dist. cap and ignition control module and still not getting a spark.

Can you tell me exacty (I'm not as mechanically inclined as you) how to test the purple wire with my ohm meter. I've never used it b4 as it was my dads long ago. Also one of the wiring harnesses that lead from coil to ignition control module has a fused lead in the middle of harness.

Thanks,

Mike
 
OK, what you have is a DELCO EST electronic ignition system.

There is NO ballast resistor in this system.

Go to the coil, disconnect the connector with the purple and grey wires. Set to voltmeter to read volts-DC. connect to positive lead of the voltmeter to the connector at the end of the purple wire. Connect the negative lead of the volt meter to ground. Turn key to on; it should read the battery voltage (nominally 12 vDC). If ok, turn key off, remove voltmeter, and reconnect the connector to the coil. This checks to see if the batery voltage flows to the system with the ignition switch on. If No 12 v on the purple lead, the kill switch may be the cause. Most usually interupt the +12 VDC feed from the switch.

Are you sure there is a fuse in the harness between the coil and the distributor? Rather unusual, but possible. If a fuse, make sure it has continuity.

Lots of carbon on the old rotor; since that was changed, it should not be an issue.

Last easy check - key OFF. Get the the BACK of the TACHometer. Remove the grey wire from its terminal and tape it out of the way so it doesn't contact anything. see if the engine fires with the wire off. If it does, replace the tach. One promminent failure mode is an internal short which keeps the coil from sparking.
 
You can probe both sides (connections) with the red lead of the voltmeter while the black lead is connected to a good ground. should show battery voltage on both sides, with the key ON.

If you have a "jumper lead", use it (short length of flexible wire with alligator clip on bothe ends).

If neither side of the kill switch has battery voltage with the key ON, make sure battery voltage is present at the IGN terminal of the switch with the key ON. Some riggers will fuse the ignition lead (purple wire) at the ignition switch.
 
The never ending saga of The Colonel vs The Boat. So far boat is winning.

Checked voltage on b+ Purple wire and got 12 volts with switch on and also got 12 volts when I pulled center plug wire from distributor. However when I pull a plug wire off a spark plug and test with red lead of volt meter and crank engine I get nothing.

Tried issue with tach and removed gray wire. Still no crank. Looked at my kill switch and it only has 2 purple wires going into it. Not a lot of room to maneuver.

Any other advice before I get my shot gun and put this thing out of its misery.
 
Don't use the voltmeter to check ANY of the spark plug leads or the coil output....when working, the system will produce a high enough voltage to turn the meter into elecronic scrap.

With +12VDC on the purple wire, the kill switch is OK.

Try checking the pickup coil as you don't have much left to be wrong. Two small leads going into the module.unplug from module. either one should show infinite resistance to ground. Ohm meter to both leads, polarity doesn't matter. should be 500-1500 ohms going on memory. If it has shorted to ground or is open, the pickup coil is the issue.
 
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