1991 Yamaha 2 stroke wiring in gauges, trim gauge prob

win-or-bin · 11 May 2020, 15:47

Hi all,
During lockdown and renovating an old I last owned nearly 20 years ago, to power her I am fitting the same type engine she had, a 50hp yammie 2 stroke 1991 model, when I got the engine it had 703 remotes but no gauges, I managed to get a set of the orange numbers old analogue gauges on eBay, got the tach wired to the remote no problem, the trim is another matter. It's the strange 4 wire sender on mine, pink, orange, grey +black
From what I can understand orange needs to be 5v constant feed and is supposed to come from the tach? I don't have an orange wire coming from the tach?
If I run a 12v supply that I can put through a voltage regulator Rand adjust to 5 volts will it then work the trim gauge? Sorry if this doesn't make sense, it's weird the tach didn't have the orange wire as they were NOS sold together for a old yamaha.
The middle photo are the wires from the trim gauge.

Davie · 11 May 2020, 19:09

the trim sender unit is nothing to do with the Rev counter wiring. Power up the trim gauge using the yellow and black. Connect the colours from the sender unit to the colours on the trim gauge and it may work but at this time you got various senders and gauges but some are not compatible with others. Going by the pics you have bullet at the engine and the more modern square plugs at the gauge. Try it, they grey wire is possibly not used.

spartacus · 11 May 2020, 19:21

Similar question came up a couple of years ago. No sure if this is a help or hindrance? Any Yamaha number or code on the trim sender - so people may be able to identify compatibility?
https://www.rib.net/forum/f37/yamaha...ing-79992.html

win-or-bin · 11 May 2020, 20:18

Thanks for the replies, someone told me the 5v supply actually came from the tacho? Will have another look, I actually saw that post but another couple posts I have seen contradict it, usual story! Davie if I use the standard yellow switched live then it's 12v? This is the weird trim sender that requires a 5v constant live? Could try it tomorrow, thanks for the input guys ��

win-or-bin · 12 May 2020, 12:56

No if I hook up 12v the trim gauge shows fully trimmed out, if I then connect pink to pink, orange to orange black to ground nothing changes. The trim sender definitely requires a 5v constant feed from what I can tell, I am going to try and use a voltage regulator to drop a 12v positive feed to 5 volts and supply that to the sender and see what happens, not much else I can do? Thanks for help, will keep you posted for the good of the thread incase anyone else is trying to rewire an antique ��

win-or-bin · 12 May 2020, 16:33

Update! I have checked when the guage is connected to 12v as suggested and it is outputting 5v orange wire as a reference voltage for the sender, connected all up it just shows fully trimmed out no matter the position of the arm, so looks like the sender is caput, probably not worth getting a sender from Yamaha as A) will cost about 130quid , B) I will probably order the wrong one.
Thanks for all the help, on the very slim chance anyone has one please message me but looks like I will be shelving the trim guage until one turns up
Cheers

win-or-bin · 12 May 2020, 16:34

Thanks

Davie · 12 May 2020, 20:44

It’s maybe not the sender, it’s an issue with getting the correct sender to match the gauge. We had heaps of issues when trying to mismatch different years when the 40-90hp included these oem and it’s that long ago I canine remember what fits what but I seem to remember you need the gauge with the white 4 pin plug with the round pins not the square plug with the square pins to match the sender with the 4 bullet connection.

spartacus · 12 May 2020, 21:33

Like this Davie?
https://www.ebay.co.uk/itm/YAMAHA-TR...-/253748115952

win-or-bin · 12 May 2020, 21:44

My trim gauge came with a 4 pin block connector, I took out the pins for ease of connecting up to spade connectors etc for trial and error, I am trying to find a fool proof way of testing the old 4 wire trim sender to see if it's functional, appreciate the input and realise these things are old tech now!
Thanks
The tach gauge and trim sender were sold together but obviously this could coun for nothing as they were both NOS and thought I had got a rare bargain so may be different years etc and incompatible as you say .

Davie · 12 May 2020, 22:29

Quote:

Originally Posted by spartacus

Like this Davie?
https://www.ebay.co.uk/itm/YAMAHA-TR...-/253748115952

Yes, with the round pins. I’m sure they are work on a different resistance.I will go digging when I go to work. Chances are I have one somewhere.

win-or-bin · 13 May 2020, 09:10

Wow, awesome, I will await what you find, if not is there an aftermarket trim gauge that would work with my sender?
Thanks so much guys for the continued help

Davie · 13 May 2020, 19:53

I went digging today and got 3 trim gauges out that have slightly different wiring out the back but all the same colours. Took a new sender unit out the bag and connected them and guess what, none of them were comparable with each other. Do you know the part number of your sender unit? If not come to Dundee and collect these gauges and connect them to your sender and hope your sender matches one of them.

win-or-bin · 13 May 2020, 21:42

Wow, Davie, that's above and beyond, clears up what the issue is then, superb, thanks. After looking I don't even think my engine is a 91, as far as I can see it's maybe 1985, the manual says 50 DETO,? Will try and dig and see what sender it would have for that year, was on eBay today and a second hand trim unit came up, similar wires to the above one posted by Spartacus and it was only 15 quid so bought it, looks like it probably won't work either though......thanks for the offer to come to Dundee and try them, spot on, fair trek for me as I am in Campbeltown but after this lock down carry on is over may take you up on that if I am up near you.
Appreciate all the help, slightly regretting not just chucking a newer 4 stroke on the back instead of trying to period correct and relive my younger years with and old yamaha two stroke!!
So glad Yamaha didn't do a normal trim sender like everyone else years ago !

win-or-bin · 18 May 2020, 14:25

Update, not that this exact scenario will probably affect many people anymore, anyway next trim gauge has come, older style with round pins, connected up and suprise, doesn't work, just shows fully trimmed out looks like I am flogging a dead horse trying to find the right gauge for the sender.
Cheers

spartacus · 18 May 2020, 15:06

Quote:

Originally Posted by win-or-bin

Appreciate all the help, slightly regretting not just chucking a newer 4 stroke on the back instead of trying to period correct and relive my younger years with and old yamaha two stroke!! So glad Yamaha didn't do a normal trim sender like everyone else years ago !

These Yammie engines are bullet proof if properly maintained and 50hp is still worth a few quid. Besides at this rate you'll be opening up an EBay shop selling nothing but trim gauges!

Have you definately ruled out the sender unit as being faulty?

Hope you get it sorted.

win-or-bin · 18 May 2020, 17:08

Thanks!
In the service manual there are no definitive resistance or voltage readings for a trim sender test. Went out today and wired up one of trim gauges! And supplied 5v to the sender, checked the ohms reading but can't get a reading, if I change to voltage on the multimeter I get a low voltage reading on the pink wire, I forget exactly the figure but when I move the arm on the sender this doesn't change? I presume it should but also feel it should work with a resistance change?
If the sender is faulty, which I am now leaning towards, they seem to be virtually non existent. I can find loads of the newer two wire sender's none of the older so I feel this may be the end of the road.
Thanks