90hp 2 stroke oil sensor

[bosvark01]

Hi guys I have a 90hp yamaha 2 stroke and recently whilst fishing in a wake free area ie not wot, noticed red oil light activation on dash gauge. nil alarm or safe mode (difficult to ascertain due to slow speed) . stopped checked oil level = full. travelled 400m to boat ramp and quit whilst I was ahead and trailered boat.
I have checked and ascertained that the float has not stuck and drained the two stroke resevoir.float switch/sensor removed and whilst connected tested alarm and additional dash light works fine,confused as well as buzzer.

Here is the problem I am stuck with, there is a float/collar that moves up and down the float shaft, whilst testing the red oil light activates when the float is at its HIGHEST point and then switches off from the 3/4 mark down to empty, obviously when reaching the lower the buzzer and additional red light activates on dash gauge.

Why all of a sudden has this occurred, as not normal for red light to be on, if oil tank is full and never did this in the past?

If this is the sensor, how can one be sure before I replace sensor? I have checked the continuity across the switch with multimeter and get a buzz from multimeter when float collar at its hightest(007ohms) and then as collar drops(would be low fluid level) the buzzer on multimeter then stops(294ohms).

thanking you in advance as I am a bit stumped to say the least.

[boats.net]

There are two switches in that sensor, should have continuity between black and green wire when float is all the way up and continuity between black and green/red wire when float is all the way down. make sure filter around sensor is clean enough for oil to pass through it.

[bosvark01]

thanks Boat.net
I have checked the continuity and has at top and bottom nil in between but when connected the float moved manually by hand,ie dry nil oil, to top activates oil light(red)???

[bosvark01]

have checked previous threads of sensor problems and seems according to these the sensor might be good if so then why the red light (oil light) on gauge

[99yam40]

If the switch is working properly then you need to be looking at wiring.

Does this rig have the remote oil tank also, Or just the one on motor?

[bosvark01]

just the one on the motor and have checked the individual wires(ie red and green + green) between the motor and the gauge using continuity buzzer and seems good.any thoughts???????

[99yam40]

Trying to understand how this thing works.
If the green is grounded then redlight should not be lit.(top switch closed)
If green is not grounded then redlight should not be lit (top switch open)
Green/red grounded then redlight and buzzer should be on( bottom switch closed)

There has to be something in the gauge that decodes the switches positions that is not working

Top switch should light a green light is my thought not red

[bosvark01]

have to agree but never recall a green light on gauge but anything is possible.
what stumps me is the gauge the way its presently operating is showing red light when full, then off at middle level, then buzzers and safe mode at low level.will try the earth test and report back hopefully before you wake up.

[bosvark01]

to solve some confussion I have an anologue gauge(yamaha) with only two red lights one is oil level(problem light) other is, I presume, an engine problem light as this is activated when motor overheats due to water problems etc. including when your oil level drops and motor overheats activates with buzzer - tested this works fine just the red oil level light which is activating on full oil rather than low

[bosvark01]

I agree with 99yam40 about the red light should not be lit but I dont have a green light, that I know of.........

[bosvark01]

Hi Chaps

still battling have checked the loom between motor and gauge as well as wiring through 703 remote all good.So to revisit the problems.......

2stroke oil switch sensor on motor when the collar/float is at the top/full of oil a red light(oil can light for low oil level) activates on gauge (pro -series II analogue -two lights one red oil can and one red temp light) when at the bottom works as it should ie temp light,buzzer and presumably the safe mode activation until you reset by switch off.have bench tested gauge and seems fine as for what I have read up ie top section closes a switch then middle switch off and then the bottom where activation with need to reset.

Decided to try take boat for a spin to see if any difference on the water knowing she has been pumping oil - motor goes fine then noticed rpm gauge stopped working needless to report red oil can light still active(full oil resevoir on motor) and no change.

[B]Question 1[/B]: is there a method of testing these specific analogue gauges
here a pic of one like mine:

Yamaha Pro Series II Analog Tachometer, Black | Outboard Parts Yamaha Mercury Evinrude Johnson Suzuki

Question 2 : Has anyone ever had the same problem or similar or just me with neptunes curse again??

Only repair or event leading up to this problem is the trim and tilt relays replaced at the motor, I know supposed to be a solenoid apparantly but previous owner replaced soleniod with relays probably due to cost and about then when I replaced the relays did all this start - all fine up to that point.

any suggestion???????please help

[99yam40]

I would think if it started when you changed the T&T relays, then you must have did something to the wiring to cause it

[bosvark01]

thanks.......sort of figured that. was hoping for a test regime for gauge and sensor.

[boats.net]

The analog(white face or black face) tach with single oil light requires a adapter relay, 6Y5-81950-00-00 to make oil light function properly, if you just put a new gauge in it need to install relay at tach, if tach was working ok then relay may need to be replaced.

[bosvark01]

thanks for the reply.no new gauge but cleaned the wiring and replaced a few dodgy looky connections here and there so may have been on before but not seen.I take note of this relay but where would I find it as I have searched the loom front to back only place I have not looked is in the 703 control box.is there anyway it would work without this relay?Thank you