Recent content by trashboat

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    1990 mercruiser 4.3 no spark

    Compression test was good, all cylinders around 150 or so. Checked timing again, same results. I tried different rotor I had laying around and it decided it wanted to run, but only when pouring fuel down carb. Carb is pretty crusty looking so I imagine that's my next step. Thanks for all of...
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    1990 mercruiser 4.3 no spark

    Checked spark at coil with gap tester and have strong spark, plugs I just verified spark with an in line tester. Intake hasn't been off as far as I know, I'm just chasing down the no start.
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    1990 mercruiser 4.3 no spark

    Okay I did try this yesterday while I was messing around and it still didn't fire, can't remember if it stopped backfiring or not though.
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    1990 mercruiser 4.3 no spark

    Cylinder 1 is TDC, rotor pointing at cylinder 1 plug wire and timing mark at 0 degrees. That would the compression stroke right?
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    1990 mercruiser 4.3 no spark

    Cylinder 1 is TDC, rotor pointing at cylinder 1 plug wire and timing mark at 0 degrees. That would the compression stroke right?
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    1990 mercruiser 4.3 no spark

    Correct it's lined up with #1 spark plug wire on the cap, with cylinder 1 piston at TDC
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    1990 mercruiser 4.3 no spark

    Yeah I poured some fuel down the carb and gave it a little sniff of ether and it sputtered/backfired the same. If compression is good, it's getting fuel and has spark I'm not sure what else could be the issue unless it's the distributor itself shorting out, but if that was the case I'm not sure...
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    1990 mercruiser 4.3 no spark

    Correct I have spark at the plugs, and the engine cranks strong and sounds as it should. I don't believe it ever had any compression issues, but I was going to check compression next to be sure. I can take a video of it tomorrow cranking, and it does seem like it wants to start it's sputtered...
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    1990 mercruiser 4.3 no spark

    Firing order is correct, set the base timing with cylinder 1 at TDC, distributor rotor pointing at cylinder 1, and lining up 0 degrees on the timing mark, and still not firing. Checked several times and it all seems to be correct, I think the previous owner put a distributor in is it possible...
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    1990 mercruiser 4.3 no spark

    Verified this today, going to pull the plug for cylinder 1 tomorrow to put cylinder 1 at TDC to set base timing.
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    1990 mercruiser 4.3 no spark

    New sensor was connected the same as the previous two. Yes it's backfiring while cranking .
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    1990 mercruiser 4.3 no spark

    Replaced the sensor again and have spark now, third time is the charm. Still won't fire but I suspect that's a timing issue, had it backfire a couple times. Thanks for all of the input, it's appreciated
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    1990 mercruiser 4.3 no spark

    I only tried it while grounding the white and green wire, but yes it's connected to the coil and grounded. I can try it while cranking the engine over later. If there's no spark while cranking but spark when grounding the wire, what does that indicate? I'm also going to exchange the sensor...
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    1990 mercruiser 4.3 no spark

    If you mean the distributor sensors, the first one was but the one that's in there now is a quicksilver.
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    1990 mercruiser 4.3 no spark

    Correct, grounding the wht/grn rapidly I have spark on my spark gap tester. Verified firing order, rotor rotates and have correct voltage at wht/red wire, and coil. Going by the thunderbolt IV troubleshooting diagram everything seems to point that the sensor in the distributor is bad, but that...
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