I turned a motor into scrap iron and this was the cause. The boat came from higher altitude, (Lake Powell) and had been tuned accordingly. I exchanged the metering rods using the smallest ones I had in my kit but that wasn't enough.......BOOM

Thanks for the help guys. Im going to run it again Sunday then pull a plug for another look.

You may already know this, the reading is most accurate if you can just turn the key off at the RPM you want to check.

Yeah, i know.
thanks.
ealked into napa thisd morning ans ssw a edebrock 1409 marine for 500. Almost did it lol.

Don't know if you can trust it, https://www.ebay.com/itm/Carburetor-...from=R40&rt=nc

seller has zero feedback on zero history.. shipping is 2 bucks..
Seems legit :)

Thanks for the link, wish it could be trusted!

Best of luck !!

Thought I would post back.
Changed the wires and coil, turned up the timing from 30 to 32* all in. I did see some corrosion in the coil socket and the timing strobe that used to be erratic is now very steady.
Runs much better now. I saw (analog) 5000 RPM with decent pull. I killed the key and pulled #5 plug. Looked nice and tan. I have some pics on my phone I can put up later.
I feel there is still more in the box performance wise but it's close now.
Thanks much.
John

I have done a few vortec set ups, normally they do not like timing over 30 total, they themselves raise compression. last I did I had comp grind a custom roller to make max power @ 5500, using performer RPM intake and a 600 edelbrock runs very well, It is in a light sterndrive setup. I did a twin engine setup a while back, ran ok but never performed like we thought it should...but it was on old shortblocks(killed heads why we went vortec) jump ahead current, one engine got overheated and killed, so bought 2 reman for builder in Fl and now one is down on power after very few hours, just getting into this as we speak..