Interpreting Alarm Sounder Meaning

[nwwhalerguy]

I am in the second season with my 1994 21' Outrage, all is well except today I heard a high pitched alarm or warning tone inside the console after running the boat at higher revs albeit briefly for the first time this season. My gut tells me this might be related to the oil pump for the two stroke Yahama, but I don't know what to make of it. Any input appreciated

[Phil T]

Really need to know the make, model and year of the engine.

Was the tone constant or repeating?

Was there a pattern?

What were conditions when it happened?

What changed to make it stop?

[jimh]

Generally a boat does not have an aural alert sounder. Usually an outboard engine has an aural alert sounder. Usually the cadence of the aural alert sounder has to be interpreted by the operator based on advice the manufacturer of the engine provides in the operating guide for the engine. Read the engine operating guide and look for advice on how to interpret the meaning of the aural alert sounder.

[FL21WAC]

Having recently been schooled in the ways of Yamaha two-stroke alarm states; here is my contribution:

Assuming your Yamaha engine is a 1994 or similar vintage; the alarm could be caused by one of two states:

1. Overheat; the thermostat switch in the head closes at about 180-degrees-F. It is easy to check. Put your hand on the top of both of the heads of the engine, just above the top spark plug. If you can't hold your hand there for a five-count, then the engine has likely overheated and thus the alarm. A digital thermometer would also be a good investment if you plan to dabble in owning and operating this vintage outboard motor.

2. Low oil in primary (mounted to engine) oil tank. Is the little tank on the engine almost full? If not, is the pump in the secondary (big, remote 2-gallon) tank running?

If you like, report back with the outcomes of these two items for next steps.

[jimh]

The configuration of warning signals from an alarm sounder is specific to a particular engine brand and model. There are two very common situations for an aural alert signal to inform the operator of a problem:

--engine high temperature is usually signalled by a thermal switch; when engine temperature exceeds a particular threshold the switch closes. The switch is usually employed to operate an electric aural sounder. Because of the thermal inertia of the engine block, once the thermal switch closes it generally remains closed for several minutes or more, and will remain closed for as long as the engine temperature is above the switch threshold. This means a continuous aural alert tone usually signifies overheating.

--low oil or oil reservoir level below minimum is usually signalled by a float switch; when the level in the oil reservoir falls below a particular threshold, the float switch closes. The switch is usually employed to operate an electric aural sounder. Due to motion of the boat, the oil level in the oil tank can vary, so the float switch may rise above threshold and shut off the aural alert. In some designs, the float electrical switch is not just a simple mechanical switch, but includes a mechanism for modulating the alarm. This gives the low-oil alarm a particular cadence that allows the operator to identify and distinguish this aural alarm signal from others.

In very old outboard engines the aural alert sounder was often operated by several sensors, so the operator had to interpret the situation and the cadence of the aural alert sound to determine the cause. Beginning in the 1990's outboard engine manufacturers began to isolated the wiring of the several alarm sensors and provide indicator lamps on their engine instrumentation that would clearly indicate which sensor was signalling an alarm condition; in those systems the aural alert sound was the same for all alarm conditions, and the operator relied on the illumination of an indicator lamp to show the cause. Installation of manufacturer OEM gauges with these indicator lamps was often an option, so there is no basis to know precisely what sort of engine instrumentation might be employed with a particular engine on a particular boat. And not all manufacturers provided this improvement.

As mentioned previously, reading the engine operating guide will always provide an explanation of the specific aural alert or alarm sounder methods being used on an engine.

An article in the REFERENCE section gives advice on how to interpret engine alarm sounder signals for an OMC c.1990 engine. See

Warning Horn Signals
http://continuouswave.com/whaler/reference/warningHornSignals.html

The article is an excerpt from the manufacturer's operating guide for the engine. Similar advice should be found in every engine's operating guide.

[nwwhalerguy]

I ran the motor for about 30 minutes at 4,000-RPM, then took off the cowling, checked the head temperature, and found [there was no reason for concern about the cylinder head temperature].

I checked the oil reservoir on the engine; it was full.

[Previously when the alarm had done off] the reservoir was half full.

The alarm has not sounded since then.

I have [read] engine manuals online. I don't have the manual on my engine.

[The reading of the manual I did has caused me to think these engines] periodically have alarms sounding for less cause than mine apparently did.

I will continue to monitor the [engine temperature] and oil [reservoir level].

Any other info you may offer would be appreciated.

[Phil T]

Still did not answer the request for basic information.

WHAT ENGINE DO YOU HAVE?

[jimh]

Since the poster still has not told us what engine he is asking about, we can make some guesses. The original poster mentions Yamaha and two-stroke and that the boat is c. 1994. So perhaps the engine is a c.1994 Yamaha two-stroke. The original poster mentions the boat is a 21 OUTRAGE. Maybe the boat has twin 70-HP Yamaha or twin 90-HP Yamaha engines. Or maybe a single 150-HP Yamaha or a 200-HP Yamaha.

Maybe the original poster will reply and clear up the mystery.

I used to have twin c.1987 Yamaha 70-HP two-stroke engines. They had the Yamaha Multi-function tachometer gauges, and the gauges had two annunciator lamps, red, yellow:



Going not by memory but from intuition, I bet the red was for high engine temperature, the yellow was for low level in the oil reservoi. I don't remember what the green thingamabob was for. But if I looked in the operator guide, I am sure it would explain exactly that each lamp indicated.

I think that c.1987 gauge worked on all Yamaha of 70-HP or more.

[jimh]

Hey PHIL--we got another clue. Notice that previously the oil reservoir level was HALF-FULL, but now the oil reservoir level is FULL. This is a big hint.

Since no mention was made of adding oil, I am going to guess that the mystery engine has another oil reservoir tank that is external to the engine. This is a feature on some Yamaha engines. The external oil tank will pump oil to the under-cowling reservoir oil tank whenever the under-cowling oil tank level drops below the threshold of a float switch. The float switch operates a pump at the external tank, which then runs and refills the internal tank to a higher level. In this way the Yamaha oil system keeps a reservoir of oil that can feed into the fuel system by gravity, which is a very simple way to move that oil to the oil mixing pump and mix it with the fuel.

This two-tank system is only used on the larger horsepower engines. So I am going to modify my guess and say the mystery engine is a Yamaha 150-HP or 200-HP two-stroke c.1994.

I wonder if the boat is rigged with the nice Yamaha Multi-function tachometer gauge with the annunciator lamps?

[nwwhalerguy]

Sorry for the slow replies, I am at my lake place in northern Maine, no internet here. The engine is I believe a 1994 saltwater series Yamaha 200. It has two separate stock gauges, both not functional except for the tach aspect. Yes, the engine has a large tank for oil in the center console, and as I am learning form these posts, the tank on the engine appears to vary in oil level and so calls for oil only as it dips below the float switch trigger point. The motor is in great shape for the age, appears to be original to the boat, which has 572 hours.

[FL21WAC]

I would humbly submit that 4,000 rpms is too tame a test drive to determine if you have a high speed overheat. Run it at 5,000 rpms for 20 minutes or so and see if you get an overheat.

[jimh]

The older Yamaha outboard engines were somewhat famous for the quality of their wear parts. This was an intentional ploy on the part of Yamaha to introduce their product to North America. I had a friend who ran his c.1990 Yamaha engine for more than ten years without replacing the water pump impeller. But eventually all water pump impellers need service.

If you don't know for certain the exact age of the water pump impeller on your used Yamaha engine, and you suspect that an engine overheat might have occurred, have the water pump serviced. Get a new OEM impeller and seals. You can probably run for many years with a new OEM-quality replacement part.