I recently purchased a 97 Fountain Fever 32 with Twin 502's. The STBD engine's oil pressure suddenly jumps all the way up and the low pressure light comes on. It randomly happens at idle, middle, and high RPM ranges. It has Gaffrig gauges. If I shut it down and restart the motor it usually goes back to a normal reading. I may have to restart it several times to get the normal reading. The gauge also doesn't zero out when I turn the key to the 'on' position. Does this sound like a gauge/sender issue or could the motor oil pressure suddenly jump like this?

sounds to be a sender malfunction.

Ground Wire On The Gauge Could Be Loose.

Is there a sender for each motor? Where is the sender located? Thanks for your help.

typicaly they are on the bottom of the block, just above the oil pan , on the left side of the engine, or port side of boat. the older models used a single wire sender. should have a blue wire going to it. if the wire is brown it is oil temp if equiped. tan with a blue stripe is low oil pressure alarm. i only mention this due to the boat not being new and other hands being in there moving stuff around.

when ordering a new sender call livorsi and match the sending unit to the guage you have. 0-60. 0- 90 etc,,,.
and ask for todd when you call he rocks and knows his stuff.

good luck

The gauge not zeroing out with the ignition on and engine off and the red light on when there is good oil pressure leads me to suspect the gauge is going bad internally.

Now how's THAT for a run-on sentence?

My junior high English teacher is turning over in his grave.

not bad. not as long winded as some i ve seen on here, but not bad.

also good input.