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Expensive Beeps?

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nic9

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I have a 2009 Mariner 60efi 4-stroke with low hours which is giving an intermittent alarm (6 beeps). VesselView software on my phone says it's "Critical Overtemp" but I have checked with an IR thermometer and the water jacket temperature sensor area shows around 50 degC which seems correct. The pump impeller is recent (20 hours ago), I have replaced the thermostat, and replaced the water temp sensor though both seemed ok. I opened the water jacket cover and it's very clean inside. Water flow from the tell-tale is good. To trigger the alarm, I run at cruising speed for about 10 mins then come down to idle speed and the alarm sounds after about 5 mins. The engine then goes into reduced power mode. I can clear it by turning off the ignition and then re-starting. I have run out of things to investigate other than changing the ecu which is an expensive exercise! Can anyone suggest what the problem might be?
 
If your information is correct, then your IR gun is bad. The operating temp at thermostat or even sensor, should be 145 degrees....not 122.....can you test your gun on something like a meat thermometer....at around the same temp?
 
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Thanks for your input timguy. According to my service manual the thermostat opens at 48-51 degC. In any event, the problem was there before I swapped out the thermostat so I'm reasonably sure the fault is elsewhere. The alarm started occurring during routine use last summer, there was no event such as water blockage etc which triggered it. The only thing slightly out of the ordinary was that the boat didn't get used much so it was lying for weeks without the engine running, but as I said previously the water passages look perfect (I gave it a good flushing with Blu Thru) and water flow looks ok. The alarm nearly always occurs when the engine is idling after running fairly hard for a while.
 
nic9 said:
Thanks for your input timguy. According to my service manual the thermostat opens at 48-51 degC. In any event, the problem was there before I swapped out the thermostat so I'm reasonably sure the fault is elsewhere. The alarm started occurring during routine use last summer, there was no event such as water blockage etc which triggered it. The only thing slightly out of the ordinary was that the boat didn't get used much so it was lying for weeks without the engine running, but as I said previously the water passages look perfect (I gave it a good flushing with Blu Thru) and water flow looks ok. The alarm nearly always occurs when the engine is idling after running fairly hard for a while.
Click to expand...

Post the Serial Number.
 
Here ya go, brother. If a motors operating temp is below 140, damage will occur in time.....especially on a 4 stroke where oil is recirculated. Furthermore, the hotter that you can safely run a motor.....note I said SAFELY.....the better it is for economy and efficiency. Why? Fuel is effectively burned, (as long as air/fuel mixture ratio is correct), and more power is generated. In the perfect world, the cooler the temperature that the fuel/air mix is presented at the moment of combustion, the more power will be produced......but.....the motor will be at full operating temp.
 

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For clarification, here is the thermostat info from the manual and the serial number plate on the engine:



 

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Okay thanks, that's very clear. The thermostat "begins" it's opening to regulate temp at 122, but max flow is not allowed until 145.
 
Does it go into guardian mode ( limp mode) ?
Does it have ecm in the front with 2 plugs or 1 plug? If it does I'm pretty sure 6 beeps is iac, map or tps.
 
Yes, goes into guardian mode. Yes ecm at the front. I've also seen diagnostic info which identifies map or tps (but not iac), or ecu flash check sum problem. But the fact the software is telling me it's a critical overtemp brings me back to the ecu fault possibility.

However, I've just been speaking to an experienced outboard tech and he was willing to bet the problem is a partial blockage in the water delivery pipe where it enters the bottom of the power head. There's a grommet that gets distorted by salt crystals and obstructs the water flow. So I will investigate that first.
 
I don't think it has a poppet valve, there is no mention of one in the manual I have.
Plug on the ecm looks ok but I don't know how I could test it?
 
Mikey N.C. said:
Poppet ?
Click to expand...
"Ignoramous" here butting in but an interesting post and I think I can help. Poppet is for high speed operation. I read 5 minutes at low speed and the alarm comes on. I have had poppet and stat problems and know how each of them "feel" to the operator. Stats are bypassed at higher rpms as the popoff lets cooler water (than the opening temp) pass through the block...I know I have a temp gauge on my engine and I can monitor block temp.

Big guns like fuel pressure sensors. I am a 3-4 cylinder 75-125 hp 2 stroke guy...what do I know........with these engines, on the rear of the engine, the water jacket cover that would cover the "head" if Merc had one separate from the engine block, encircles the spark plugs, is usually, near the top right side, a ⅛" NPT pipe plug. A person would pull it off and get a pressure gauge and read the water pressure in the block...5 PSIG slow 15 fast are a couple of numbers you see kicked around. No idea as to what nor where 4 strokers have for pressure access and don't know if a sensor is already used and installed, nor if it has one, is it feeding the ECU, if it is functioning and accurate......a point you might want to investigate.

If you have good pressure and the engine (obviously) is running pumping/circulating water, pee is good even though it comes off the exhaust manifold on my engines, your pipe from the water pump to the bottom of the engine block shouldn't be the problem........soooooo, back to ECU?????
 
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Ok I. May be ignorant. Texasmark. That's fine with me ok. I'm not that educated as you . off subject , your 2 strokes. With poppet valves stuck open does what ? Makes motor run rich correct? Which does what ?. Makes it run cold ? I'm asking ? Cause I really would like to know.
Nic9, was asking if new or older ecm. Older had 2 plugs , newer had 1 plug at ecm.
From experience the 1 plug ecm. Can get hot an throw 6 beeps. I chased a mercury 50 for 6 beeps for 4 months . took to mercury dealer and was told that the high voltage to map, tps or iac. Was problem. Well the ecm sends only 5 volts to these sensors, so how can that happen
No one could answer that question. I'm only using the cdi meds program. That's why I took boat to mercury dealer. Well there program said same thing. Well I purchased a ecm for motor, installed put in lake and boom got solid alarm. Problem was a thermostat full of sand.
I know you've replaced this. But obviously this motor ran hot and would give the 6 beeps and go into guardian mode. The 6 beeps is not overheat. I'm just telling you what my experience was on fixing same situation. Sorry texasmark I'm a working mechanic trying to understand this .
 
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