Mercury optimax 225hp sensor fault

neil.mccrirrick · 31 May 2016, 19:47

Hi,

I have the above engine with three faults on the smartcraft gauges. I'm getting there re fault finding but could do with some help

First one is fuel fault. There is no sender from the tank, sometimes it reads 93litres in the tank, other times it faults. Can I bypass it altogether?

Second one is trim fault. I've located the trim sensor and have yet to check the wiring. If the sensor is stuffed any advice where I can buy one? Engine is a 2001 with a warranty replaced 2003 power head

Third one and most annoying is a water temp alarm. After a lot of reading I've discovered that this is an outside water sensor to let the ecu know when the water is freezing etc so it adjust oil mix etc. I think it's this one that sets the alarm off 4 beeps every 2 mins arghhhh

I don't know where this is on the engine I assume cylinder head? If anyone can let me know where to look that would be fab and again if it's not wiring where to get one?

Motor has been stored and is now back in use which is where the faults are coming from. Runs and pumps water fine so I'm fairly sure this is just annoying stuff

Thanks

Neil

Sent from my iPad using my finger

whiskylee · 31 May 2016, 20:44

Neil have you downloaded the smartcraft & optimax 225 operations manual ? They are there if you google search them for free. I think the paddle (speed) sensor is also temperature sensor

neil.mccrirrick · 31 May 2016, 20:57

I have but can't find much about this tbh or where it is. If I can find it I can test it 👍

whiskylee · 31 May 2016, 21:03

Page 34 no 16 shows temp sensor

http://www.hedges-uk.com/boat/Merc/o...nd%20Above.pdf

whiskylee · 31 May 2016, 21:16

Temperature Sensor
Three temperature sensors are used to provide cylin- der head temperature information to the ECM. A sen- sor is mounted in each cylinder head and one in the air compressor cylinder head. The ECM uses this in- formation to increase injector pulse width for cold starts and to retard timing in the event of an over-heat condition.
An ohms test of the temperature sensor would be as follows:
Insert digital or analog ohmmeter test leads into both TAN/BLACK sensor leads. With engine at tempera- ture (F_) indicated, ohm readings should be as indi- cated ±10%.

neil.mccrirrick · 31 May 2016, 21:56

That's super helpful thank you very much. I'd found the operation manual and the smartcraft manual not the service manual. Top man 👍

neil.mccrirrick · 20 June 2016, 18:43

I thought I'd update this for anyone that searches for info in the future

Some of what I now know is blindingly obvious in hindsight but there you go. So in no order

Master reset won't fix or remove faults. They will clear when the problem they are signalling is cleared. If the guages say there is still a problem there is

Access to smartcraft guages to calibrate is different in different models. Holding minus and plus down works on many. On mine it's hold down minus and plus and then turn the ignition on then press mode to get into calibration. It took some searching to learn that

neil.mccrirrick · 20 June 2016, 18:45

There is a water temp sensor that is not the engine temp water sensor. This sensor is checking the outside sea temperature to aid cold water standing. It can be turned off in calibration and the engine will be fine

neil.mccrirrick · 20 June 2016, 18:50

If you see an oil warning saying 100% left either your aux tank is empty or blocked basically the engine is taking oil from the small tank on the block and it's telling you that

If that tank starts to empty it can airlock when you put oil in the aux tank. To clear that fill the aux tank. Take the cap off the oil tank on the engine and run the engine. Be careful. The tank will start to fill and oil will flow out. When it's full put the cap back on. This will bleed the system and the alarm will clear

neil.mccrirrick · 20 June 2016, 18:52

If you get a fuel tank warning and its not empty it either needs calibrating or he sender is broke. You can set the guages to no fuel tank present in calibration. This will remove the alarm or you can obviously calibrate

neil.mccrirrick · 20 June 2016, 18:59

If you get a trim sensor alarm you will find the sensor on the port side of the engine. Trim right up and you will sea a small part with three wires going to it, if it's a digital trim. The wiring routes to the starboard side of the wiring loom. If you disconnect the wires you cannot clear the fault. If there is any voltage (around 5) it's the trim sensor that is broke. On some guages I believe you can tell them there is no trim sensor and bypass this. Couldn't do that on line you will need to buy a sensor. But you don't need to re install it. Mind is tucked in the loom where it will stay dry. The guage thinks it's at one trim level so the alarm has gone . This does not affect trimming it running. You can of course reconnect it all and then re calibrate

whiskylee · 20 June 2016, 20:29

Sounds like your getting to know the opti & Smartcraft system very well Neil, have you been out on the boat with the opti ?

whiskylee · 20 June 2016, 21:06

Neil I keep forgetting are you putting quicksiler quickclean in you fuel ? There was a Mercury bulletin that came out mid 2000's recommending using it to stop carbon build up.

neil.mccrirrick · 20 June 2016, 21:27

Hi pal test run on a local lake a few days ago went like a dream really happy 👍. I'm not using any quick silver products but I know it may be a problem. I'm hoping this will reduce coking http://www.rockoil.co.uk/cm/images/p...ure_marine.pdf

Had nothing but a good experience with rock oil. MP3 ultra made for dfi 25 litres was around £115 delivered I think

neil.mccrirrick · 20 June 2016, 21:28

Engine sounded very sweet and was smokeless once warm 👍