2002 4.3 turns over will not start.

OK, I pulled the boat out for the first time this year. Put it on the dog ears in the drive way and it fired and ran well on the 4th attempt. Ran if for 30 min or so at idle and up to 3500 rpm. No problems. Took it out to the lake for a run and it would not start. Turns over, but will not fire. Brought it home, charged the battery again and still the same results. Turs over, will not fire.

Re: 2002 4.3 turns over will not start.

safety lanyard(man overboard)

Re: 2002 4.3 turns over will not start.

Carbed or MPI? What drive? Serial numbers are a good thing on this forum.

Re: 2002 4.3 turns over will not start.

wrvdb said:

OK, I pulled the boat out for the first time this year. Put it on the dog ears in the drive way and it fired and ran well on the 4th attempt. Ran if for 30 min or so at idle and up to 3500 rpm. No problems. Took it out to the lake for a run and it would not start. Turns over, but will not fire. Brought it home, charged the battery again and still the same results. Turs over, will not fire.

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First up I see a smoked water pump impeller. Did you read the owners handbook? Or is it (like everyone else :facepalm tossed aside complete with the plastic wrapper still on it? It VERY CLEARLY states that the engine is to be run at 1300 rpm, not idle, not 3500, but 1300 rpm when on ear-muffs/flushers....

And running it at idle on flushers will cause water reversion in the exhaust system... You most likely have water in the engine now....

Re: 2002 4.3 turns over will not start.

Don S said:

Carbed or MPI? What drive? Serial numbers are a good thing on this forum.

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Thunder bolt V, Carbed. Can not read serial # on carb cover. Drive is OM401967. There is a GM# on the block.

Re: 2002 4.3 turns over will not start.

Only bumped to 3500 rmp. Good to know though. Check oil and it looked fine. Also check oil pressure switch and it worked and jumped it out to make sure fuel pump ran. Did not change position of man over board switch and it ran the first time. Will jump it out, but where? also are there any other safeties to be checked?

Re: 2002 4.3 turns over will not start.

There is a metal tag on the back of the block just above and aft of the starter. Digital camera can see it if you can't see it.
This is a number you must have.

Here is a troubleshooting chart for no spark.

Re: 2002 4.3 turns over will not start.

the only # I saw was 14099090M, it was not on a tag, but in the cast?

Re: 2002 4.3 turns over will not start.

At step 4 I had around 11.6 volts. I will pick up a spark gap tester tomorrow. Thanks for the chart.

Re: 2002 4.3 turns over will not start.

wrvdb said:

At step 4 I had around 11.6 volts. I will pick up a spark gap tester tomorrow. Thanks for the chart.

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Is that the same voltage as at the coil in step 3? If so, go to step 5.

Spark gap tester.... = Spark plug....

Just plug a spark plug into the end of the lead from the coil and lay it against the engine block. Then do the test.

Re: 2002 4.3 turns over will not start.

Hope I can help with your problem I just went thru this with my 1997 4.3. If you have no spark I have learned a few things that it could be that has not been mentioned. The tachometer can short out and ground the coil . Take the grey wire off the tach and it will rule this out. Also if you have a alfa outdrive disconect the shift interupter switch on the top of the engine on the shift linkage and check for spark. This also grounds the coil if bad. Also the dead man as mentioned above.I would start with the interupter first and check for spark. After you rule both of them out also I would use the chart above as mentioned. As it turned out for me my module was bad. They say the module rarley goes out so I would look close at all things that ground out the coil. The pickup in the distributor is one thing that goes out more often. The chart will guide you to figure that out. Good luck with your repair.

Re: 2002 4.3 turns over will not start.

While spark gap testers are fine, a free, easy way to check spark is to pull the coil wire out of the center of the distributor cap, hold the end of that wire 3/8 to 1/2" from a good clean unpainted ground and crank the engine. Spark should easily snap a blue/white spark across that gap with no problem. Was checked like this for years before spark gap testers were common.

At step 4 I had around 11.6 volts

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This voltage should be the same as step 3 as achris mentioned, and also the same as battery voltage or very close. If your battery is only 11.6 Volts, the engine will not start. It will crank over very slowly, but won't start.

Re: 2002 4.3 turns over will not start.

thanks for the input. I will check the above tomorrow. My coil primary had a resistance of .6 ohms. the auto parts store said it should be between 1.2 and 1.7 ohms. also my fluke read an open on the secondary side (should be 6.5k-14.5k). I do not know if mine reads that high. I will bring it to work to test.

Re: 2002 4.3 turns over will not start.

also, I had battery tested and it was fine.

Re: 2002 4.3 turns over will not start.

One of my favourite 'tricks' is a voltage drop check. It checks to make sure that there is no bad connections/voltage loss in a circuit. Most understand about measuring voltage, stick the meter black on a good ground and probe with the red and read the voltage... But if you put the meter leads across the same circuit and dial the reading down to the smallest scale, like 200mV, then you'll be looking at any voltage lost in the circuit.

Example. Your coil voltage. We know from the circuit diagram that there should be no 'device' that will use voltage (best way to put it, not completely accurate, but it works) between the battery positive post and the coil + terminal. So, put the red meter lead on the positive post (not the terminal, the post itself) of the battery and the black meter lead on the + terminal of the coil, with the key ON of course. What you should see is a reading of 0, or extremely close to 0. If you have a reading of more than about 50mV, then start looking for a bad connection.

It's a most effective method of finding a bad ground, because you can do it in the negative circuit too. Example. Put the meter black lead on the battery negative post, and the red lead on the body of the starter motor. Now operate the starter motor. See any more than about 10mV, you have a bad connection between the battery and the stater motor. The reason for the lead on the post itself and not the terminal is because corroded terminals are a big culprit. If you suspect a dirty post, just meter between the post and the terminal, it will show up there too.

Good luck,

Chris......

Re: 2002 4.3 turns over will not start.

I tested my coil on a better tester at work and found its reading w/in spec. My battery voltage is 12.5 volts, when I check the voltage at the coil it is 11.5 volts. When I lift the leads from the coil I will read 12.4 volts on the lead to the coil? I going to replace the coil and go from there. Thanks

Re: 2002 4.3 turns over will not start.

does anyone have a detailed circuit diagram of the electrical system? thanks

Re: 2002 4.3 turns over will not start.

Re: 2002 4.3 turns over will not start.

thanks. I am looking for a replacement coil. Mine is a mercruiser 392-805570-1? is an 392-805570-a2 the same? Sierra #?

thunderbolt V ingnition

Re: 2002 4.3 turns over will not start.

I had the coil out of the boat, sitting on its side and it leaked oil?