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    Mercruiser Thunderbolt ignition Question

    I timed cold start. It is just under 5 seconds to get ignition to spark.
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    Mercruiser Thunderbolt ignition Question

    My TB V is similar to your MPI as it only does the long spark delay when engine is cold then once engine is warm it fires up right away. There is no ECM on my set up so it must be the TB V doing it. Is there a sensor on the side of the engine that sends a RPM/Tach signal to the TB V? If so...
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    Mercruiser Thunderbolt ignition Question

    I have the 3-wire. I was having sporadic no-spark issues So replaced the following parts -Spark Plugs -Coil (this was the ittermitant culprit) -Distributor Cap & Rotor -Rotor position sensor (3-wire) in Distributor That is how I noticed the long spark delay when starting. The engine has done...
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    Yes
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    You are absolutely correct It might be no significant change at all ... just my imagination .... and yes I was using the pitot tube speedometer.
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    And here is a picture of one of the plugs that were pulled It is very black and carboned up and same model # as engine sticker
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    Here is the sticker on the top of my engine You can see Merc is calling for AC 41-101 Iridium plugs gapped to 0.060 This is what they installed at the factory in 2010
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    I installed NGK TR6 Nickel plugs they came factory gapped to 0.039" but I regapped them to 0.045 per Mercury Service Manual #25 for GM V-6 262 CID (4.5L)
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    Pulled the Original Factory Installed spark plugs and found AC DELCO p/n 41-101 The plugs look fouled with black carbon from running too hot/lean These plugs have the following attributes: Iridium Heat Range =4 4k-7.5k ohms resistor Gap 0.060 Socket 5/8 (16mm) Reach 0.68 in (17.5mm) short...
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    No I switched from iridium to standard plugs
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    Yes this is what I am thinking. I am leaning toward the thermostat as the culprit... as plugs basically all do the same thing. But I am looking for someone with experience to weigh in to verify.
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    Just to be clear .. my boat runs great and even turns off now when I want it off. There is no more run-on issue. I am asking if the changes I made would reduce my performance. The performance loss I am experiencing since changing plugs/thermostat i is very minimal but noticeable: -Boat does not...
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    Mercruiser Thunderbolt ignition Question

    The TKS carb has an automatic choke system. I am using a timing gun to watch for spark. It is very consistent in the way it starts.. I have to hold the starter on for 4-5 seconds.. as soon as the ignition sends the spark the engine fires up right away.
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    No I did not touch the mixture screw on the carb. I just backed off the "idle speed screw" ("A" in picture below) on the linkage to lower the idle RPMs
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    4.3 TKS "Run On" fixed but Slight Loss in Performance

    I have a 2010 Mercruiser 4.3 TKS with Alpha Sterndrive V6 with 2 BBL Carb and Thunderbolt V Ignition (Engine s/n 1A612644) that has problems with run on. I read through Mercrusier Service Bulletin 97-17 "Engine Dieseling or Running-On" and have made the following changes to my set up in this...
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    Mercruiser Thunderbolt ignition Question

    I have a 2010 Mercruiser 4.3 TKS with Alpha Sterndrive. V6 with 2 BBL Carb and Thunderbolt V Ignition (Engine s/n 1A612644) Recently I have been troubleshooting the TB V ignition system. I have a question about how...
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    Mercruiser Thunderbolt V Ignition No Longer Available

    I have a 2010 Larson 1850LX it came with a Mercruiser 4.3 TKS with Alpha Stern 4.3L V6 with 2 BBL Carb and Thunderbolt V Ignition (Engine s/n 1A612644) Thunderbolt V Ignition Module p/n 861251-1 is acting up. Sometimes it works and lately most of the time it doesn't. If I do get the boat...
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