2007 f40 alarm

[powder09]

2007 40 hp oil alarm comes on still runs on idle
wont speed up oil level is full, does anyone have any ideas??

[boscoe99]

My idea is that either the motor has low oil pressure, high engine temperature, both at the same time, or there is a wire issue or part issue.

Is this a model with carburetors?

Is the alarm low oil pressure related or over temperature related? Or do you not know?

Does the motor have a Yamaha tachometer installed? Some tachometers will tell you why the alarm is sounding. Do you have a trim gauge installed?

Not a good idea to run a motor with the alarm sounding. Some bad juju might happen. The alarm means to turn the motor off and investigate what is going on.

[powder09]

3 cyl carb
no gauges
don't know if oil or temp, water is circulating
how can I check oil pressure?

[boscoe99]

Unscrew the oil pressure switch and plumb in an oil pressure gauge.

[powder09]

thanks for your help

but where would the pressure switch be?

I guess it shows that I am not too knowledgeable!!!!!

[boscoe99]

Item 36 in this illustration.

2006 and Later F40BTLR Yamaha Outboard ELECTRICAL 2 Diagram and Parts

[rodbolt17]

it is a switch.
hook up an ohmmeter to it and see if it opens .

[boscoe99]

Oil pressure can be checked by ohm'ing the switch?

[dray0151]

it is a switch.
hook up an ohmmeter to it and see if it opens .

If it is a switch the OHM meter would show if it the switch is bad as it would not open there by telling the system no oil pressure even if there is some. If it opens then the switch should be good and the problem really would be low pressure, would that not be correct?

[rodbolt17]

it is a switch.
when running normal it is off.
it will close if pressure is lost at about 5 PSI or so.

it is simple to test.
if it opens when you start it go chase another bunny.

if it fails to open then either the switch is bad or you actually lost oil pressure.

my bet is on overtemp.

[boscoe99]

If it is a switch the OHM meter would show if it the switch is bad as it would not open there by telling the system no oil pressure even if there is some. If it opens then the switch should be good and the problem really would be low pressure, would that not be correct?

OP's question was about checking the oil pressure. Not about checking the switch.

Checking the switch would a good idea.

Switch is normally closed. Oil pressure opens it. Lose oil pressure, switch closes and the buzzer sounds.

If the switch fails closed then the alarm will sound even if good pressure.

If the switch fails open the alarm will not sound even if lost oil pressure.