My Quick Fuel 800 marine has been absolutely a dream for four seasons. I have tuned it twice in that time but I also dont run anything but non ethanol.

The stuff they sell down here they claim is non ethanol fuel is not. We have tested almoat every station around. Put a splash in a glass jar, 2 days later nothing but a white sticky gum like residue.

Don't get me wrong this holley is doing fine. I just think carburetors arw better suited for a drag strip than a boat I want to cruise around in. Sometimes idle for extended periods in no wake zones.

The thunderbolt is an hei unit and is nice because the advance is done electronically rather than with springs and weights which can rust and bind up. Also Sierra sells the caps and rotors can get them at napa.

And you have 4-5 different timing curves/total advances modules available, all plug and play.

Apparently I have this thunderbolt misunderstood. Can someone explain to me how it takes different timing curves without a mechanical advance?

I take it it has a little module that retards or advances the timing by the rpm of the rotor? Sorry I've never dealt with this, always had points, vacuum advance or controlled by ecm.

Hunter, I sent you an email with the different modules and their advertised specs. You simply unplug one module and plug in the one you want and of course reset max advance with timing gun. As far as the Merc T-Bolt distributor I can not remember ever seeing one rusted up.

Well I'll be. That clears it up. Thanks gary. I guess I need to toss the hei in the toolbox for a spare if the thunder bolt ever dies whIle I'm on the water.

It's highly unlikely that if will fail. I would just buy a spare module and sensor for in the distributor. Also the factory marine carb with the correct cam in a merc black motor will idle for hours without building up and fouling plugs. I have had the same carb on a 350mag since 92 and it's never been rebuilt. It still fires right up and runs flawlessly. Buy the factory merc carb for the 454 mag or the blue 500. Then tune it properly and you won't have any issues. I have a 454 gen vi I had put together for a 496 with the 500 carb on it. I can idle around with no issues. Is all Bout the proper set up. If your jets are to big and the carb needs rebuilt you will foul plugs and have issues. I'm not trying to take away from your Tbi ideas I just think you throwing money away. The carb is simple and cheap and it works great in the marine application because they are all mechanical. No electronics to get wet and fail.

I just built this carb and it seems to be doing fine so far. The plugs looked fouled but I belive due to lack of fire. The coil wire didn't look very good and the mercruiser plug wires were probably original. The Taylors should be coming in any day now. I put new plugs in last night. The cap and rotor look good but I will probably go by the parts house and swap them out just to be sure about it.