Stall alarm but engines running?

[MaddyDean]

When running, whether at slow or cruising speed, every once in a while I get an alarm that sounds like the stall alarm.

When I get this alarm, I check all the gauges and all looks good.

I also slow down gradually and/or quickly just to try and stop the alarm.

there does not seem to be a common denominator and when it happens and when it stops.

I also checked the engine SYNC and although not perfectly centered, I would bring it to center and still the alarm will go on.

Does anyone have any idea on what this could be?

Much thanks in advance.

 

[rondds]

Vince
Do you have a systems monitor panel?
Hard to see but this is what it looks like...

At startup, when the ignition is in the ON position, the alarm you hear is signifying low oil pressure - b/c there's NO oil pressure with the engine off. Whily you're running,there are many things that can cause the alarm to sound - low oil pressure, high water bilge pump triggering on, overheating, oil pressure, transmission (not sure if it's TEMP or PRESSURE but you don't have transmissions anyway). If you have a systems monitor panel, the appropriate idiot light will come on. If you don't, you have to track down the problem. Could just be a bad sensor somewhere. Your thermostat housing probably has two wires - one goes to your temp gauge, the other to the alarm. Point is, this could get confusing.

To rule engine temperature you can always confirm with an IR laser temp gun or just put your hand on the exhaust elbows. They should not be too hot to touch.

 

[Dave S]

About the only other thing I can suggest is to check the oil levels in your outdrive reservoirs (assumming that 1991 models have reservoirs because low oil levels can trigger an alarm) If your gauges look normal then I think you will probably have to have a Technician look at the problem. I also don't know if the 91 models have engine ECMs or not but in either case they can probably figure out the problem.

Dave

 

[MaddyDean]

Thanks:

rondds, you are right, I cannot see your system panel in your picture however, I do not have one, Just a standard dash; Oil, Temp, Tack, Voltage, engine sync, trim (actually works) and etc.

I just got her back from the mechanic and only got out twice--since this boat is new to me, other then a test ride, that is all i went out. Did not hear the alarm on the test drive.

I never knew that the stall alarm was actually a Oil pressure alarm, but that makes sense, and the only way I can intentionally recreate the alarm is to turn the key into the on position but not start the engine. so it does sound exactly like that oil pressure alarm.

Being that it just got back from the mechanic, I will admit that I did not check the levels (Sorry--I am embarrassed) so that is the first thing I will do tomorrow.

I will update y'all asap--Thanks

 

[Alegria]

My thought would be either you do have a temp or oil issue and your gauge or sender for it being oil or temp is faulty. Or maybe its a high water alarm? Although on our old boat (90 280) our high water did not sound the same as an oil or temp alarm... High water was more of a buzz. We have a monitor panel on our boat now and it really make those alarms easy to diagnose!!!

 

[tobnpr]

The fact that the temp and oil pressure gauges indicate normal would seem to indicate a sender problem as was mentioned.
Because it's intermittent- with no rhyme or reason as you say- I would first check for a loose wire at the sender.

All engines are different and I have no idea where yours are located, but check the sender wires at the oil pressure and temperature switches/senders that are connected to the alarm. If the connections are good, I would replace the offending sender.
Most are normally "open" switches, so when the alarm occurs you could check with a VOM to see which one is closing the circuit and causing the alarm. Since it's intermittent, though I'd probably just replace both of them (they're cheap).

 

[MaddyDean]

Update:::

I was finally able to get to the boat and checked the engine oil. The PORT engine is way overfilled. At least 1/2 inch above the fill line but More toward 3/4.

Could the overfill be the reason for the intermittent alarm?

Regardless, I will siphon to acceptable level.

 

[Bill Z]

There is a low RPM control that gets fried on a regular basis because they are poor quality. Just replaced one. The alarm goes off every few minutes in two beeps.

 

[MaddyDean]

Still getting the alarm but have some progress and of course more questions.

I Purchased a IR Thermometer gun and started the boat;

Twin 5.7's. each engine has two risers (Starboard and Port)

So I am checking the Starboard engine and starboard riser as the engines are warming up and noticed the starboard riser is easily getting hotter quicker the the port riser.

So I check the Port engine and sure enough, the same thing. the starboard riser is getting hotter quicker then the port riser.

Let the engines warm up and took another reading.

Starboard engine:

• Starboard Riser:210-degrees
• Port Riser: 150-degrees
• Dash Gage: 175

Port Engine:

• Starboard riser: 200-degrees
• Port riser: 150
• Dash Gage: 170

My question, is it normal for the starboard risers on these engines to run hotter?

 

[rondds]

ALL your riser/elbow readings are too high. These should be somewhere in the 90-120 degree range. You may have occlusion in the elbows or you may have manifold problems. This warrants some disassembly to be sure.

Rule of thumb - you should be able to hold your hand on the exhaust elbows without getting burned while the engines are running. I'm assuming you took readings with the engines on. When you power down, things heat up quite a bit before they start cooling down so readings on stopped engines are not representative.

 

[MaddyDean]

ALL your riser/elbow readings are too high. These should be somewhere in the 90-120 degree range. You may have occlusion in the elbows or you may have manifold problems. This warrants some disassembly to be sure.

Rule of thumb - you should be able to hold your hand on the exhaust elbows without getting burned while the engines are running. I'm assuming you took readings with the engines on. When you power down, things heat up quite a bit before they start cooling down so readings on stopped engines are not representative.

Yes, all with the engines running--even took her for a run and quickly checked the temps with engines still running.


In one forum the guy changed his water pump. he had the same scenario, new impeller and the works.

when he took apart the water pump (I am assuming there is a water pump on the engines) there was sand and salt. so he started dismantling the risers and salt accumulation was huge.

so, I took off tomorrow and getting an early start--hopefully I can do things while in the water else I will get her lifted and go to town.

Gonna try de-salter and such. Depends on who is at the marina tomorrow, one guy will hoist her and not charge, all others will charge.

here is my confusion. why are both engines reading as-like temp but only the starboard giving me the alarm. .

Thanks for your insight--this is learning for me.

lastly, this is a cheap gun, since I am off I am going to take her to my mechanic just to use his stuff--since he offered for free.

 

[rondds]

Good question. The alarm sensor is usually in the thermostat housing, as is the sender for you dash temp gauge. You need to shoot readings at each thermostat housing to see what the temp there actually is. Maybe a bad gauge, maybe a bad sender or sensor. Follow the trail of HEAT and see where it is.

As for being a cheap temp gun, as cheap as it may be it's still pretty accurate. Boil some water on the stove and see if it shoots 212 degrees if you want to see how accurate it actually is. If it's off it's probably only off by 1-2 degrees.

 

[MaddyDean]

Solved--Knock on wood.

Here is what I did and so far (five times out--further each time) and so far, I have not received any alarms any more.

I had the Marina short hull the boat two Saturdays ago. I purchased some "Salt Away" (http://www.westmarine.com/webapp/wc...151_10001_37894_-1____ProductDisplayErrorView)

I flushed both engines with this stuff and on the Port Engine I could see salt pissing out the exhaust.

Took her out for an hour with now alarm (Longest I ever went.

Came back to port and changed the oil for good measures and since then I have not had an Alarm--Knock On Wood

Thanks for all your help.