Any reason not to pressure wash my 454 Mag MPI in the bilge at the car wash? If I do the whole compartment am I risking contaminating the trim tab and drive reservoirs? Are the electronics hearty enough to withstand the power wash? It just seems like a good thing to do before getting to work on the tune up.

You'll have different thoughts on this but I've done it many times on my scarab and no issues at all.I dont wash the engine at all.Water will spray on the motor but not enough to hurt anything.I'm pretty darn picky when it comes to having a clean engine compartment and boat in general.Like I said,I do it all the time.

I do it evrey time i use the boat. I just make sure that i only use high press under the engine and slight press for every thing around the trim pump and batts.

I wrecked an MSD distributor on a carbed engine from washing it with a preasure washer. I did it more than once. Moisture got into the spark advance and rusted it out.

Just FYI....