F225TXRD fuel pump amp draw

[fairdeal]

I had time today, so I made some measurements.
All key on, engine off, I manually grounded the driver to run the pump.

As far as I know, both the lift pump and the high pressure pump are the originals installed by Yamaha.


the amp draw on the lift pump appeared to start at ~.7 amps,



and build to a max of ~2.5 (the VST was full, so the pump was "dead headed"



I also disconnected the leads and put an ohmmeter on the lift pump; saw ~ 1.1 ohms




While i was at it, measured the HP pump too; that drew a max of ~ 4.5 amps

[boscoe99]

Looks to have been very foggy down there today.

Are you going to determine what device(s) are powered by the 5 amp fuse for us?

[fairdeal]

not foggy, but hot, humid, and in direct sun: couldn't see the iPhone screen to adjust the focus.

unwrapping the harness to confirm would be a fairly tedious job.

the Yam SM - Mercury too - is pretty clear that 5 amp is a sub-fuse solely for the LP pump.

and it is also - along with the HP pump and "a lot of other stuff" is behind a 20A

I'm unable to imagine their rationale...

[boscoe99]

You got me. I forget to cross reference the Mercury SM.

I am longing for hot and humid.

[boscoe99]

the Yam SM - Mercury too - is pretty clear that 5 amp is a sub-fuse solely for the LP pump.

From where are you getting the "pretty clear" part from the Yamaha SM?

It is muddy as the Mississippi to me.

[fairdeal]

yes, most of the Yamaha schematics are frustrating,
think its going to show complete detail and then multiple leads disappear into a bundle

but there is this one:



zoomed:




(wouldn't have recognized it if I hadn't already seen it clearly from Merc)

[boscoe99]

Ah so. I did not think to check there. Will have to try and remember. Remembering is getting harder every day.

Pity the poor guy who opens a Yamaha SM for the first time. Makes his head want to explode.

I particularly like this Yamaha diagram. Initially made me think the hot positive wire was connected to a ground.

[cpostis]

not foggy, but hot, humid, and in direct sun: couldn't see the iPhone screen to adjust the focus.

unwrapping the harness to confirm would be a fairly tedious job.

the Yam SM - Mercury too - is pretty clear that 5 amp is a sub-fuse solely for the LP pump.

and it is also - along with the HP pump and "a lot of other stuff" is behind a 20A

I'm unable to imagine their rationale...

Fairdeal,
Like most people, you are under the impression that fuses are intended to protect the device it supplies.
"The primary task of a fuse is to protect the circuit wiring that is connected to it, against overload and short circuit. The circuit fuse is not intended to protect the terminal devices that the circuit suppliers".

Here's a link to an article dealing with "Classic Bikes" That further explains.
http://www.jampot.com/techtips/electrics/fuse_part1.pdf

[fairdeal]

I particularly like this Yamaha diagram. Initially made me think the hot positive wire was connected to a ground.

an error? or they intentionally mis-used standard electrical notation....

[99yam40]

bad drafts man drawing the print and no one caught it be for sending it out

[boscoe99]

bad drafts man drawing the print and no one caught it be for sending it out

Fujimotor was so proud of his first drawing. Now you go and burst his bubble.

He is a millennial. The company dared not criticize him or he would have been unhappy. He would have needed a space place to hide from the likes of truth tellers such as yourself.