Helping friend with '86 454Mag motor.
Having power issues...have new plugs, wires, coil, cap and rotor, yada, yada, but the boat just was not making any power.
Played with timing, and it would either just make it on plane, then go fine, or it would get on plane and only make it to 3000 rpm. Thinking it might be the Thunder Bolt (IV?) ignition controler. Boat ran fine last year with same set up.
Thoughts?
If it is the "Box", would you get one from "BAM" or the likes, or would you go with an after market like MSD?

Thanks.

borrow a know good module and try it first. I have a 24 degree v-8 if you wanna try it.

Wow..thanks. I'm with you.
I've got a call out to a couple of friends who may have a good one (swaped to MSD).
But I may just take you up on it. Thanks

This is so silly I hesitate to even suggest it, but take a look at the rotor and make sure it is for an 8 cyl.

Don't ask me why I know to check that.

Of all the silly things Ive done, somehow I missed that one.

Also check that the distributor hasent moved and is tight. You should check timing at 4000 rpm at the dock to make sure its advancing.

check and make sure the timing mark ain't movin around,that it stay's steady on the mark at 2500 rpm's up,if not your distributor gear could be worn throwing your timing off.

Thanks.
Forgot about that one. My old BB-Charger did that to me back in ....oh never mind, it was a long time ago...
Damn nylon gears...

Or rotor loose on distributor shaft, which happens a lot if you dont locktite it on.

Had the same problem with a HP 20 module that I got from a friend that got it off ebay. Idled fine, etc., would not make any power past 3200 RPM. Try a different module.

BTW... The MSD will not work without the module. The module controls all of the timing.

If you are using the aftermarket crap, try merc parts. A while back someone had problems using aqua-power cap and rotor. May be worth a try.