Bad ground on F150

[mx beach guy]

Maybe this will help someone.
Went to start boat last wensday'!st day of vacation"
motor started and an we were headed to fill up an
she cuts off and theres no power on the dash wiggle the
batt switch an cuts back on.Start up an minute later same
thing loose all power.This goes on for an hour so back to
slip an pull cowling off start tracing for loose connections
an finally found the main ground wire wiggle back an forth.
Cleaned an retighten an she aint never started this good the
motor turns over seems like twice as fast.Seems this is the cure for the
batt problem we were having couple mounths back.Guys ckeck your
ground wire.

 

[bigeye2k]

Where is location of the ground wire. Thanks

 

[mx beach guy]

behind the fuse panel if your in the boat looking at the
motor on the right side.Its connected to the block.

 

[Mayda Marine]

I have a 2005 Parker 2520 with twin Yamaha 150 4 strokes. I found the same problem with both of my engines. My bolt that was holding the DC engine ground wire/cable to the engine block on both engines was loose. But the biggest problem was were the engine block was painted outside and also inside of the ground bolt threads left little contact with the actual engine block. I sanded off the paint on the outside contact area of where the DC ground terminal was held by the bolt as well as running the bolt in and out of the threads several times to try to help remove the paint inside of the threads for better ground contact. This solved my twin engines problem Big Time.