Intermittent stalling and I loose all electrical power?

dockman62

Recruit
Joined
Jan 22, 2011
Messages
4
I have a Yamaha F150, manufactured in 06. I purchased used a year ago with 20 hours on the engine. It has run flawless. It had all filters serviced when I bought it. I keep stabilizer in the fuel routinely, etc. I have run it every month over the winter for 2-3 hours to keep it exercised. This weekend I took it out and several times it "missed" when under moderate load or when running at 3500 rpm. I thought it was fuel and maybe time for new filters. However it started shutting down after it stalled. When shut down the motor wont crank, and I have no power to the trim unit including the trim button on the side of the motor. I have check and secured all battery connections (using lock nuts not wing nuts), and tried a new battery (that I load tested to make sure it was good). It shut down three times but eventually trim starts working and motor will crank and start fine. I realize I still may have fuel problem, but I want to start with why I am loosing power to the trim unit? I have checked and jiggled the trim fuses on the port side of the engine. Does/could the starter relay cause a loss of power to trim unit? Does the ECM/engine brain shut down all power when it senses an issue. When I have this problem, my voltage guage on the dash does not measure any power, but my depthfinder unit tells me its seeing 12.4. My fuel and Trim guages also have power, but in this condition the fuel reads 5/8s instead of the 3/8s that I know it has?

I'm new to the forum, thanks in advance for any help. I had to leave the boat at the lake, so I will have to go back to get the serial number.
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,270
Re: Intermittent stalling and I loose all electrical power?

You are having a connection problem. Follow the cable and look for any swelled places in the rubber. If you get a nick in the rubber, it will allow water in and it will corrode the inner wire. Also clean the connections on the engine where it connects on the starboard side.
 

dockman62

Recruit
Joined
Jan 22, 2011
Messages
4
Re: Intermittent stalling and I loose all electrical power?

Thank you. I will track those down. I did inspect the connections on the motor and they were clean and tight. I did read somewhere there was a service bulletin for early f150s on this connection? I can't seem to find the details on this? Am I correct in that if I have no power trim, it has to be something in the battery connection or the engine harness? Why would the volt meter on the dash gauge show no power, but the depth finder connected to the accessory switch shows 12.4 V? Is this a clue of something?

Again thanks for any advise.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,116
Re: Intermittent stalling and I loose all electrical power?

A good hand held volt meter is your friend, start measuring to see where voltage is and where it is not
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,270
Re: Intermittent stalling and I loose all electrical power?

Owners need to understand that there is 2 electrical systems on a boat. There is the engine harness and boat harness and both operated independent of each other. Engine, gauges and trim is one harness where running lights, horns, bilge and electronics are on another. The only common link is the battery.
 

dockman62

Recruit
Joined
Jan 22, 2011
Messages
4
Re: Intermittent stalling and I loose all electrical power?

I get that and a good point that made me think. So the dash volt Meter operates off the key switch. And the depth finder does not and they share the same battery. So I know it is a motor harness issue? Correct me but if I focus on the trim circuit not working that old be a more direct path to the problem? So what I know is that trim was dead, motor would not crank, no solenoid noise. Battery tests fine and I checked all connections and even tried. A second battery was also tried. so in the motor harness?
 
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