225 sho blowing fuse. help please

[99yam40]

where are you measuring this 9.65v for the relay?
Is it coming from that fuse that keeps blowing?


one input to the ETV relay is from the fuse , that continues on the the ETV once the relay is energized,
and the other is to energize the relay

Fuse c (30 amp) is feeding the ECU and ignition coil, VCT,& fuel injectors

looking at the print again it shows 2 wires/circuits leaving the relay, I have no idea what they go to except they hit the same plug/connector on the fuse box I guess.

looks like one does not go anywhere, just lands on the plug/connector #10
the other lands on #5 R/G wire

[boscoe99]

where are you measuring this 9.65v for the relay?
Is it coming from that fuse that keeps blowing?


one input to the ETV relay is from the fuse , that continues on the the ETV once the relay is energized,
and the other is to energize the relay

Fuse c (30 amp) is feeding the ECU and ignition coil, VCT,& fuel injectors

looking at the print again it shows 2 wires/circuits leaving the relay, I have no idea what they go to except they hit the same plug/connector on the fuse box I guess.

looks like one does not go anywhere, just lands on the plug/connector #10
the other lands on #5 R/G wire

What a great puzzle this all is.

[99yam40]

Boscoe that second one you colored yellow looks like it comes from #12 and the one from relay looks like it lands on #10 ,so it just dead ends.
Is that not correct?

The 2 you colored green to the ETV, are they just revered in polarity to move it in opposite direction?
or do they both use the back for ground, where the ECU just switches power from one to the other to reverse the motor direction?

This set up in not like most ECUs just con*****ing the ground.

the other wires P,O, P/W must be TPS

[boscoe99]

Boscoe that second one you colored yellow looks like it comes from #12 and the one from relay looks like it lands on #10 ,so it just dead ends.
Is that not correct?

Looks that way doesn't it. I think it is the crappy illustration not correctly depicting that one of the two power feed wires from the fuse is going to the R/G wire on pin #12.

Yamaha likes to make their puzzles interesting don't they?

Look at the illustration on page 5-18. It shows that the feed from the ETV fuse branches into two circuits. One goes to pin # 59 and the other goes to pin #60 at the ECU. The wire from pin #59 at the ECU leads back to pin #12 at the fuse panel. Inside the fuse panel it goes to the fuse. The illustration is just not showing it.

Imagine someone that is not conversant in Yamaha methodology madness trying to figure this all out.

[99yam40]

Looking at 5-18, I do not understand the connection between between the ETV relay and the fuse.

Edit(again) seems that far right line is a connection to positive 12 V once the main relay picks up.
so that would tie both sides of that fuse to +,
So if this is true then anything on the down side of the main relay could draw power thru the 10 amp fuse if the main relay or that fuse was bad or lost connection.
is my thinking correct?










This shows the battery fuse ,main fuse, main switch, main relay fuse and relay
also shows the symbols for the different connections.

if that connection after the ETV fuse is really there , then this could be a reason he is blowing that 10 amp fuse.
just have to figure out what has opened up.
main relay could not be picking up, or main relay fuse could have a problem

I guess that could mean even the main switch and fuse could also be a problem if that connection shown south of the ETV fuse is real

Got to wonder what all is correct in the prints.manuals

edit
thinking about it again, and if that wiring connection was there, that 10 amp fuse would be powering everything the main relay is supose to power even without the main relay power up, so that cannot be correct

[boscoe99]

It is part of the puzzle.

Something about being inscrutable.

East is East and West is West.

[boscoe99]

Your diagram has an extra black line to the right that my diagram does not have. ?????

Of which black line do we speaketh?

[HarrisonDawgs]

Looking back at my notes I suppose I was a little vague on what I said about input voltage. Specifically, referring to manual page 5-28, step 3 measures input voltage with key off (resting) from input terminal to ground. This was 12.4 volts - normal. On step 4 it says switch start on and measure input voltage between terminals b and c of relay receptacle. This voltage was 9.6 v and manual indicates it should be 12v. And yes, there are several wires that run from ECM back to Fuse/Relay unit. And yes, this circuitry is very confusing to me. Without studying it in depth I would assume it is some sort of feedback protection that facilitates an automatic blowing of the fuse to possibly protect other interests on that circuit. I admitted right from the start that electronic circuits are my pitfall. Trying to wrap my head around this but it's going to take me time. I will likely carry this to a mechanic for a YDIS hookup. I am simply trying to get a better understanding of what went wrong, how it works, and most of all eliminate anything that is obvious. For what it is worth, when I noticed the first hiccup I was in process of trying to trim the motor up a bit. Motor was on plane running around 3000rpm. I touched the trim button and motor bucked. Let off and it continued to run fine. All in all I used the trim maybe 4 times. Each time it stalled for a second (until I let off). The last time it went straight to idle (I am assuming Fail Safe mode). It will crank, change gears, idle around, trim works both ways and otherwise do everything it is supposed to do but when you try to accelerate it just limps around at 6mph and 1300 rpm. Another thing complicating this for me is that I am the second owner. Boat is a Ranger with keyless startup (wires everywhere) and when new it had a Mercury on it and was swapped to Yamaha SHO in 2010. I feel sure that some of the wiring inside the boat was intended for the Merc and some of the Yamaha wiring setups were never installed, such as their command link. Having said all of that, I have owned it for 4+ years now and have well over 200 hours of my time in it without any issues until now.
Thanks for all of these diagrams. It will take me some time but I will smoke them over real good. Good to have this, thanks again.

[99yam40]

Your diagram has an extra black line to the right that my diagram does not have. ?????

Of which black line do we speaketh?

the one labeled c on yours.
it is energized when the main relay energizes.

If you look one side of the ETV fuse is tied to that c and the other side of the fuse is powered from the power before the main relay

edit
thinking about it again, and if that wiring connection was there, that 10 amp fuse would be powering everything the main relay is suppose to power even without the main relay power up, so that cannot be correct

[99yam40]

Harrison, did you test the main relay also when testing?
Just to be sure?

Does not make any sense why they would tie power in like the print shows , so all of this may be wrong due to the print showing false info.
edit
thinking about it again, and if that wiring connection was there, that 10 amp fuse would be powering everything the main relay is supose to power even without the main relay power up, so that cannot be correct

I am trying to understand what all the a,b, and c terminals represent in that procedure that you got you bad voltage reading,so I understand where the voltage is coming from. I will look and think more about it.
edit
a should be power from the ETV fuse.as it has power without turning on the switch
b-c should be the power to pick up the relay.
I would chase that back.

that it all started when hitting the T&T switch, means to me voltage dropped causing problems some where.
I would be cleaning all connections starting at batteries and working on.
but finding exactly where the problem is would be better so you know when you fix it and what you did

can you measure voltages back from where you measured the low voltage to see where it drops off?

[boscoe99]

Harrison, did you test the main relay also when testing?
Just to be sure?

Does not make any sense why they would tie power in like the print shows , so all of this may be wrong due to the print showing false info.

I am trying to understand what all the a,b, and c terminals represent in that procedure that you got you bad voltage reading,so I understand where the voltage is coming from. I will look and think more about it.

But that it all started when hitting the T&T switch, means to me voltage dropped causing problems some where.
I would be cleaning all connections starting at batteries and working on.
can you measure voltages back from where you measured the low voltage to see where it drops off?

Are you talking about two power feeds to the ECU and two power feeds to the ETV? If so, I am guessing that it is for redundancy. They use two TPS's as well. The APS also uses redundant units.

[99yam40]

Are you talking about two power feeds to the ECU and two power feeds to the ETV? If so, I am guessing that it is for redundancy. They use two TPS's as well. The APS also uses redundant units.

no,
5-18 shows the ETV fuse( next to the ETV relay) with power from 2 different sources.
one from each side of the main relay feeding one side each of the ETV fuse

[HarrisonDawgs]

I did test the main relay and it tested fine as well. Input voltage was 12 v in both key on and key off positions. Also checked each relay for continuity (closing) with 12 volts supplied and they open and close circuit as they should. All connections were very clean. This boat is garaged and the powerhead was replaced under warranty in 2013. Looks practically new. Battery is 9 months old and terminals very clean. Don't get me wrong, I pulled it all out, cleaned it up anyway and tightened everything securely. Power trim could be involved or maybe just coincidence, I don't know. I do know I felt a huge drop in power each time I touched it but there may have been something else going on at the time and the trim motor kicking in would have made it severely worse from a power standpoint. I am going to begin to trace wires and equipment in the boat. With those keypads, 4 tilt and trim switches and gauges in the console I want to rule out any shorts if possible. Not going to be easy though, Ranger uses too much expanding foam.

[boscoe99]

Looks to be a boo boo.

Sir, yes I know it took me the master mechanic 5 hours to fix your motor. Four hours to decipher the service manual and one hour to troubleshoot and fix the problem.

[walleye1]

Take it to a dealer that can hook a 703 control box up to your engine and see if it is still blowing the fuse, that will tell you if it in the boat or not.