4.3 gi vortec will not fire

I have what I am fairly certain is a 4.3 Vortec GI that I purchased not long ago. It has a 2bbl carburetor on it and here is the story. I bought it and it had just had new fuel filters put on and the fuel IS good. it started and ran great at idle. when I would get going there was some valve ping and it would backfire in the carb so thinking the timing was advanced I took it into my local over priced shop. they said the timing was right however that my plugs,cap and rotor were well past their life. after I inspected I let them go ahead. I took the boat back out and it immediately flooded. After that she ran fine with just one small hiccup and I put it back on the trailer. Yesterday when I went to take it out it simply did NOT want to fire. So I did some tests. I have spark from the coil to the cap but NONE from the cap to the plugs I have the delco ignition. I did a little reading and replaced the ignition control module under the distributor cap. still no fire. I went back and put the old cap and rotor back on today still no fire. Anyone have any other ideas on what it can be?

Re: 4.3 gi vortec will not fire

alaskawild1 said:

I have what I am fairly certain is a 4.3 Vortec GI that I purchased not long ago. It has a 2bbl carburetor on it and here is the story. I bought it and it had just had new fuel filters put on and the fuel IS good. it started and ran great at idle. when I would get going there was some valve ping and it would backfire in the carb so thinking the timing was advanced I took it into my local over priced shop. they said the timing was right however that my plugs,cap and rotor were well past their life. after I inspected I let them go ahead. I took the boat back out and it immediately flooded. After that she ran fine with just one small hiccup and I put it back on the trailer. Yesterday when I went to take it out it simply did NOT want to fire. So I did some tests. I have spark from the coil to the cap but NONE from the cap to the plugs I have the delco ignition. I did a little reading and replaced the ignition control module under the distributor cap. still no fire. I went back and put the old cap and rotor back on today still no fire. Anyone have any other ideas on what it can be?

Click to expand...

Ayuh,.... Welcome Aboard,.... The electrical path from the top of the coil tower is through the coil wire to the distributor, through the rotor, to the post in the cap, to the plug wire to the spark plug,...

The module under the cap already did it's job, the coil fired,...

So it's either the cap, rotor, wires, or plugs,...

Re: 4.3 gi vortec will not fire

How are you checking for fire at the plugs?

Re: 4.3 gi vortec will not fire

alaskawild1 said:

I have what I am fairly certain is a 4.3 Vortec GI that I purchased not long ago. It has a 2bbl carburetor on it and here is the story.

Click to expand...

A 4.3Gi engine is EFI, throttle body injected. Are you sure its got a carburetor??

Re: 4.3 gi vortec will not fire

It's probably the GL engine. It's probably a cheap china rotor that is grounding to the dizzy shaft. If you have to get aftermarket get Delphi or BWD. I would also question the float adjustment if it flooded. Once you have it running and warmed up look down the throat of the carb. Is it dripping fuel at idle? It should be dry in there because all the fuel should be coming out thru the idle circuit below the throttle plates.

Re: 4.3 gi vortec will not fire

Is it possible this is a "kill switch" issue? Make sure your kill switch(at the helm) is in the in the proper position. It's worth checking.

Good Luck

Stalling and backfiring

Stalling and backfiring

Well I got the problem fixed! It turned out my coil was shot. The spark was simply arcing out on the bottom of the coil and not getting to the plugs.
Now I have ANOTHER LINGERING PROBLEM.....