MILD THUNDER

iTrader: (3)

Clean your ground at the block, the battery, and at the small 8 gauge wire coming from the engine harness. Also, clean your connections at the starter terminal. Wire brush them, apply some dielectric grease. Don't forget to disconnect the negative cable at battery when doing all this.

Your losing voltage throughout the boat. What you describe is a symptom of loose/corroded connections.

MILD THUNDER

iTrader: (3)

I doubt he has a crank sensor on his HP500/540 blower engine. Plus its obviously he has electrical issues since when he uses something like the trim pump or power seat motor that draws a substantial amperage, its pulling what little available amperage to the ignition and killing his gps unit.

MILD THUNDER

iTrader: (3)

I get it. You guys are talking about the Hall Effect sensor in the distributor. Never Heard it referred to as a crank sensor.

Yes, those do go bad. Although Ive found in all my years of diagnosing cars and boats, don't throw parts at it. If your having erratic electrical issues, fix that issue before replacing ignition parts.

The MSD boxes are very voltage sensitive. They will misfire and what not if you drop the voltage below about 12v to them. If hitting the trim button causes enough voltage drop to turn the GPS unit off, then its more than enough to cause the box to malfunction.

OP, what distributor are you running? Mercury or MSD?

MILD THUNDER

iTrader: (3)

Ya, I got away from the msd boxes and went to crane. The msd distributors are notorious for rusting all the parts under the caps

oneanddone

OK Guys I really think I have 2 issues going.

Checked all grounds in around motor, starter, and transom all were cleaned and tight.

GPS is wired into the spare fuse under the dash. The only thing else on the panel is the seat power when I move the port side up and down GPS stays on.. When I use the driver’s side it shuts off. The seat switch is sticking so I’m thinking something is back feeding through it and killing it. I'm going to replace it. Now with that switch unhooked I raised and lowered the tabs "one then the other" GPS stayed on! When i use the "Both" Switch it cuts out???
I ran drive up and down and the hatch also and it stayed on. So I have it narrowed down to something with Tab "Both" switch. This was with 12.9v non running motor. I think I need to re wire the GPS to a direct + source.
Now for the RPM/power loss... I think I have some ignition issues. Plugs looked ok. "Meaning even burn" some were a little more moist than other but not in any pattern. None of them looked soaked. The pickup in the distributor looks corroded. Cap, rotor and coil contact seem to look normal. Note about 130 hours on all the parts. I’ll try to post pics.

Thanks for all your help maybe this will give you guys more thoughts

MILD THUNDER

iTrader: (3)

Did you try lifting both tabs using both individual buttons at same time?

mike tkach

iTrader: (3)

jeff,im just curious,in several of your posts you have said[at the shop]do you own a boat repair shop,or work at one?

oneanddone

oneanddone

oneanddone