Safe Mode

[shadetree01]

Yamaha 40 running in safe mode. Shop said oil pump not pumping need to replace. Premixed fuel and checked while running in top carb. Vey little oil at 3000 rpms. Engine was running in safe mode, jumped switch on back to turn off rpm reduction.

What wires do I jump to make engine think it is getting oil?

How do I clean and check precision blend system?

If I can locate problem would like to keep injection system.

I have cleaned carbs and removed and checked theromstat in hot water. Engine does not seem to be overheating, can hold my hand on it and water pump is working fine although I am going to replace impeller.

[99yam40]

No one but you know what motor you have.
Always post the model #.

My guess is there is a level switch in the oil tank that tells motor it is out of oil

[shadetree01]

sorry, Yamaha 40 HEO precision blend, mid 80's I think...and yes it does say H-E-O.

Thanks for any help!

[shadetree01]

oil light on front works, green, yellow and red...

[99yam40]

Which country was this motor from?
here is a code chart for the States
Decoding Yamaha serial #?


Have you drained the oil tank and cleaned it, the lines, and check valves? I think it has check valves.
Have you tested the oil float switches,oil lights,and alarm to make sure they are functioning properly?

If they are then it is not oil that is causing reduction mode if tank has oil in it while reduction mode is keeping motor from reving past 2000 RPM.

Maybe it is the over temperature switch that is causing the problem as that switch is on the back of the motor

[shadetree01]

From what I have found motor may be from europe, but I'm here in NC. Have checked all lights and they are working and gauge in tank works. But is there some sensor that letsomoter know pump is pumping. As stated before oil coming out at #3 card is just a trace. When I jump rpm limiter to off motor runs fine. I have run around at 2000 rpm for about 1 hour and motor was not too hot to hold hand on. I marked oil level in tank and it had not changed. So it appears it is not pumping oil.

How do I pull and check temp sensor on back of motor to see if it is worling. Pulled thermostat and it opens at 130 in hot water and is all the way open at 150.

I have no buzzer sounding and am not sure how to jump it to see if it works.

Any help is appreciated.

[99yam40]

how and where are you "jump rpm limiter to off "?

never heard of an oil alarm associated to oil flow on a Yamaha, but have on a Suzuki.

on my C40TLRX you ground the pink wire on temperature switch to check for alarm, have no idea on yours. To test temperature switch pull and check with a meter while heating in a pot of water to see what temp it closes

[shadetree01]

on the back of CDI unit(where all wires run to) I think that is what it is called...there are 3 post with a metal jump that can be attached to middle and right and limiter is off, middle and left says on. Saw this when I had it off when checking wiring. It's on the back of the unit. Motor runs fine with it jumped to off.

Still need to know which 2 wires to jump to make it like oil injector was not on moter to eliminate any issuses with precision blend system.

How does temp sensor come off? Do I just pull rubber cover/plug out then twist?

One of these 2 system has to be where I am getting safe mode....

Any help is appreciated!

[99yam40]

Probably need to find a service manual for your motor as my C40 does not have oil injection and is a way later model anyway.

Do a forum search on precision blend and see what you find.

Disconnect the pink wire to temp switch just to make sure that is not what is setting it off.
Like I said before the level switch is the only one on the oil system that I know of that would bring in alarm and safe mode

[TownsendsFJR1300]

on the back of CDI unit(where all wires run to) I think that is what it is called...there are 3 post with a metal jump that can be attached to middle and right and limiter is off, middle and left says on. Saw this when I had it off when checking wiring. It's on the back of the unit. Motor runs fine with it jumped to off.

Still need to know which 2 wires to jump to make it like oil injector was not on moter to eliminate any issuses with precision blend system.

How does temp sensor come off? Do I just pull rubber cover/plug out then twist?

One of these 2 system has to be where I am getting safe mode....

Any help is appreciated!

Looking at the diagram for a 1985 40 HP:

Yamaha OEM Parts ? Outboards, Outboard Motors)

The only electrical hook up for the entire system is for the oil level at the tank (3 wires). It appears the pump itself comes as one unit and isn't broken down for re-building it.....

[BaileysBoat]

I'm on the same page as TownsendsFJR.

Only low oil alarm or high temp will trip safe mode. You should get an alarm if you try to start with the safety lanyard pulled.

Low oil level will cause an amber, then a red light. Safe mode with a red light.
A very simple system to diagnose with a manual.

I would start by verify that the low oil light works.