Problem with fuse VZ150TLRC Yamaha 150 HPDI

[AimlessRolling]

Hi all,

Went to take boat out this morning and had a few troubles. The tilt/trim would not allow me to raise the motor (I store it down and raise to tow). After many hours of chasing this problem, I will attempt to describe what I am now experiencing.

The 20A fuse marked "Main Switch Trim Switch" is blowing every time power is applied at the main A/B/Off battery switch.

I thought this may be a bad motor, so I disconnected motor from engine and motor runs fine with jumper cables attached, but fuse still blows even with motor disconnected. I have tried reading/searching, but the tilt/trim relay has eluded me, but I am suspecting that it is the small single relay marked "Main Relay" in the same panel, next to the fuse, can someone confirm.






At one point early in the troubleshooting (before I ran out of fuses :facepalm, I held in the trim switch on the motor while I turned on the A/B/Off battery switch, the motor attempted to run, but the fuse immediately popped.

Even if this turns out to be a relay problem, I am stumped as to how the fuse blows every time even with the motor completely disconnected?

Any ideas folks?

Thanks in advance,
Aimless

 

[99yam40]

Re: Problem with fuse VZ150TLRC Yamaha 150 HPDI

As you have already found out the trim motor is fine and it is not trying to run without you hitting the trim switch. So the T&T relay is not your problem.

You have a short in wiring as nothing is calling for power and it is still blowing the fuse, or you have a battery hooked up wrong.
The battery positive is going to ground or the negative of battery

 

[AimlessRolling]

Re: Problem with fuse VZ150TLRC Yamaha 150 HPDI

The battery positive is going to ground or the negative of battery

Can someone point me to a schematic of what is behind that 20A fuse? Is this in the service/technical manual, if so I will purchase one ASAP.

Thanks in advance,
Aimless

 

[AimlessRolling]

Re: Problem with fuse VZ150TLRC Yamaha 150 HPDI

Replying to my own post.

I purchased the SELOC manual, and for my specific model, the 150 HPDI VMax, (2596cc) I am finding the electrical schematics very lacking. The schematics for the other V6 engines, 200-250HP, appear to have much more detail. The schematics for the 150HP Vmax have "dotted boxes" that I would expect to be detailed somewhere, but the references do not appear to be in the book....... I am looking at pages 4-99 and 4-100. Also have looked at fig 225 on page 4-98, it provides some of the detail, but does not show the entire circuit as it references a "10P connector" that does not show the other end..... am I missing something or is this not a very complete reference?

Is the Yamaha Manual for the 2004 VZ150TLRC Service Manual, LIT-18616-02-82 (yamahapubs website has for $93.00) any better? I do not want to tear in to the system and risk damage without a solid reference.

Thanks in advance,
Aimless

 

[99yam40]

Re: Problem with fuse VZ150TLRC Yamaha 150 HPDI

Sorry, but I do not have any diagram of your motor and I looked around but could not find one.
I am fairly sure the Yamaha service manual would have it, but not sure about the after market ones as they cover too many motors in one book to have them all.

Use a little thinking to narrow it down. It is blowing fuse so you know the problem is behind the fuse.
I would disconnect the main harness from motor,and see if the problem is at motor or in harness and controls.
Maybe look at the area where main harness leaves motor, harness bends at that point or in the grommet.
Using a meter instead of sticking fuses in to see if they blow would be a better choice.

Has anyone been rewiring anything on this boat or pulled and replaced batteries?

When was last time it functioned properly?

Could rats or squirrels have gotten into the boat while sitting and chomped up the wiring?
,

 

[AimlessRolling]

Re: Problem with fuse VZ150TLRC Yamaha 150 HPDI

Thanks for the reply, everything was working fine two weeks before when I last used the boat. Nothing has been changed/wired/modified in that time and most prior modifications were by my own hand and no birds, wild animals, or rogue mechanics got near the boat during the interim.

I am very comfortable with all the boat wiring and controls, but the outboard engine has never caused problems, hence, I am unfamiliar with the components (I am very comfortable tearing a car engine apart and getting it all back together). I am beginning to understand where the relays, wiring, harnesses, etc are located - so I am well on my way. I have spent time digging here and other places so that I don't damage or make it worse trying to troubleshoot.

The schematic I located shows the 30A fuse is only protecting the power back to the trim switches (one at motor, one at helm) and they both return the direction signals to the relay (which has the appearance of a large terminal block), see pic:



So as soon as I figure out where the harness enters/exits I will disconnect both ends of the harness and begin to exercise the continuity tester across all the switches and back to the main battery ground.

More to follow......
Aimless