Looking for thoughts as to why my SB motor is having issues planning and Peak RPM WOT. Getting on plane the SB engine lags the port engines by a few seconds to get to 2800 RPM, max RPM full out is 4200 on both, full tank, ( I think the SB is pulling down the port RPM)


15 hrs since rebuild. New injectors and cal, changed plugs (swapped injectors engine to engine no change in performance). Confirmed fuel pressures. New distributors last year, no codes, confirmed timing of 8 deg. New 8mm wires at rebuild


Plan to swap upper intakes/sensors next. Vacuum likes attached, intake o-rings good. Exhaust note at idle sounds right, no raw fuel smell.


Is there a sensor that would would affect WOT that wouldn't throw a code?

Is this a new issue since the rebuilds?? What was WOT before?? Or is it a new to you boat??

Just started, was running 4800 -78mph

what do the plugs look like

Did you confirm fuel psi st the rpm/load it acts up ?

Compression test ? Newer motor doesn’t get a pass for not being checked.

ck ignition components ? How old ?

Compression was checked as was leakdown.


0% leakdown on each cylinder after rebuild.

Had an injector stick open before I bought all new. Plugs are tough to read, after 4-5 hours they ldon’t have much carbon build up to get a good color indication.

new Distributors, orig coil.

i didn’t check fuel pressure at load, yet

Definitely need to check fuel pressure under load.