hey guys wonder if someone can point me in the right direction?

having a problem where i get a lagging at speed. sometimes just lose rpm and then goes back up almost instantaneous,no backfire, other times for a few seconds and slows right down. last time it cut out and i had no power whatsoever and couldn't start it. disconnected the kill switch and reconnected and turned on and off the battery control switch a few times. got power, got it to start and limped home. its a 454 merc. i replaced the fuel filter separator but there was no water buildup in it. threw some methyl hydrate in the tanks just in case. replaced the batteries end of last season. new plugs /wires/distributor this season. where do i look next. thanks for any suggestions

Start with the basics. Check fuel tank vent, or try running with cap off to eliminate that as a possibility of why it may be starved for fuel.

IT sounds like he is losing power in his electronics if I'm reading his post correctly. I had the same sort of issue with mine once, and it was at the main harness plug on the engine. Pulled the plug, cleaned the terminals, coated with die electric grease. Put it back together, made sure it was pushed all the way in and the clamp was tight. Never had it happen again after that.

thanks fellas checked the vents and filled it up had a spillover so i know those are good. cleaned all the battery connections. pulled the switch and cleaned all those connections. pulled the coil and cleaned those wires. cleaned the 4 connections to the mercathode as well. not sure what you mean by the main harness plug. went for a short run no problem but going again tomorrow as it was intermittent before. thanks for the suggestions.

Check your kill switch clippy things I had to replace mine due to a similar issue, would cut out with no real pattern, seemed very random. Was a simple fix, hope yours is too.