I have twin 6.2 Mercruiser engines in my 07 Donzi 28ZXO, and my oil pressure gauges are all over the place. Sometimes they read right, then you throttle up and one might read right and the other drops out completely or bounces. Then more throttle and it changes again. I can be flushing engines at home in my driveway and it can go from 20-40 to slam 0 and below.

I have changed the sending unit. I was then told not to use teflon tape at all on the unit so I have removed the sending unit and removed the tape and reinstalled hoping it was a ground problem. I have pulled the instrument cluster to search for a loose or corroded wire/s, and found everything clean and tight. Ive checked what grounds and powers I can, but nothing has been found so far. I also replaced one of my PERKO battery switches since it was feeling loose. I have taken a jumper and ran from the ground on the battery to the sending unit case and still no luck.

Anyone got any ideas??? Thanks

I run nothing but mechanical gauges for water, oil and fuel pressures for that reason.