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Boat Repair/Mercruiser Thunderbolt IV timing

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Expert: tyler boehner - 2/13/2008


Question
How do you time a 454 with thunderbolt IV

Answer
You have to bypass the thunderbolt system or every time you change the timing, the computer just fixes the adjustment you just made.  The more you adjust it, the more the computer interacts and changes the timing back until you are so far off the mark that the computer can't control it anymore.  There should be a purple wire draping over the front of the motor, that comes of the thunderbolt system.  Before you start the motor, you have to unplug the purple wire and ground it out.  This will bypass the computer, allowing you to time it normally.  When you are done, hook the wire back up and you are good to go.

Boat Repair

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tyler boehner

Expertise

Basic boat motor mechanics or boat wiring. I can help the most on mercruisers, merc outboards, and johnson evinrude outboards.

Experience

Mercruiser tech. Started working on boat motors three years ago. I have limited shop time under my belt but have proven myself in our shop and am now the shop manager.

Organizations
I have a mercury tech number and a yamaha tech number if you would like, but i don't think that being a certified tech makes you a good diagnostic pro.

Education/Credentials
Three years of see and learn shop time. Two weeks of tech training at Mercuiser school at Springfield. Two update merc schools at Topeka KS. "gotta love George". Tons of "E" skills classes online. Most of my ability to diagnose came from shop time working out problems.

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