81 evinrude 90Hp buzzing

[403jeeping]

So I'm new to the forums, and new to boating. We purchased our 1st boat last fall and have only taken it our twice this spring. The first trip was except. Had a blast.

Took the boat our this evening and made a mistake while launching the boat, forgot to put the transom plugs on and took on some water. We got the plugs in and used the bilge pump t0 grain the boat. All seemed well.

We ripped around with the kids on the tube. Then blasted off across the lake to do some fishing parked the boat and upon keying the ignition up a buzzer in the control modal (throttle box/ignition box) started buzzing and when fired up still continued buzzing. There was no one else on the lake, and we were about 1 km from the boat launch across the lake and it was nothing but wilderness. So wit 3 children on boad one who was a 3 month old we made the decision to head for the boat launch across the lake to load the boat.

Boat was running fine and water was still being pumped through the engine as there was a steady stream of water flowing from the top of the out board. We ran the boat about 1km across the lake to to the launch and trailer the boat home.

Recently filled the boat up with premium gas mixed 50:1 with 2storke oil. Used the proper measuring cup to measure out the oil.

Could thus buzing be caused by the flooding of the boat? Possibly shorted something out?

Or is this an over hearing problem?

Any advice for this new boat owner would be greatly appreciated.

 

[403jeeping]

The boat is a 1983 Glaston SSV-151 with an 81 Evenrude 90 HP outboard

 

[403jeeping]

Well after doing some trouble shooting I've determined that the problem is in the temperature sensor on the starboard bank.

Now to figure out the procedure for changing out this sensor. Looks like at the very least the cylinder head cover will need to be pulled to swap out the sensor. On the cylinder head cover the wire protruding seems to be somehow epoxied into the hole with only the wire sticking out.

Has anyone done this repair them self and feels like sharing a little info with me. Would be greatly appreciated.

Also any ideas why this sensor has malfunctioned?

Today before troubleshooting I ran the engine on muffs for 15 mins at idal and brought it up to operating temperature. Both banks of heads were warm to the touch. I had no trouble keeping my hand on the running engine. Even yesterday when this problem started the heads were just warm to the touch and the boat had been operating intermediately for a good 4 hours. Other then the annoying buzzing sound the engine ran fine .

 

[Will Bark]

Check the insulation on the sensor wire to make sure wire is not grounding out on motor block or any other metal on the motor Had same thing happen to me and that what it was; wire grounding out and causing the overheat alarm to go off. Good luck

 

[thegipper]

Check the insulation on the sensor wire to make sure wire is not grounding out on motor block or any other metal on the motor Had same thing happen to me and that what it was; wire grounding out and causing the overheat alarm to go off. Good luck

I think Will is correct. Most likely there is a tear in the insulation and the wire is grounding out and sounding the high temp buzzer. I believe if the sensor was bad, it wouldn't buzz at all but I'm not positive on that.

The wire isn't epoxied into the head cover, the epoxy is part of the sensor. If you search for pictures of the temp sensor for your particular motor, you will see what I'm talking about. I still doubt the sensor is bad but most likely a tear in the insulation exposing the wire itself. If that wire grounds out, it sets the buzzer off.

 

[thegipper]

No Title



the sensor looks something like this, if not this one exactly. that sensor is mounted under the head cover.

Check the insulation closely,

 

[interalian]

Disconnect the brown wire at the knife connector under the rubber sleeve. Insulate the wire going to the harness. If the buzzer is still on, you have a shorted wire. If not, measure between the brown wire from the sensor and the black wire (or ground) looking for continuity. The sensor is OPEN normally and CLOSED during overheat.

Removal requires taking off the cylinder head water jacket. Usually this involves breaking bolts due to corrosion. Take care.

 

[Bosunsmate]

Those sensors work by completing a circuit to ground if the head gets too hot. So thats what they mean by a bare patch in the wire will cause the alarm to trip as it will contact the grounded negative engine case.
I know of no good way to check if the sensors actually work themselves.
My friend has this motor and i tell him to just keep an eye on the tellttale if he doesnt want to replace these sensors or put in aftermarket temp gauges

 

[oldboat1]

yeah, I'm not that comfortable depending on tell tales, but in combination with a surface temp sensor would feel safe (that and having done the water pump work myself). The senders are held in place at one of the head cover bolts, as I recall -- simple set up that works fine.

 

[403jeeping]

Thanks for the replys everyone. I've done some testing on the sensor.actually made a jumper wire and connected to the other bank's sensor and it still made the buzzing warning weather the engine was hot or cold. Keyed accessory or running; so I'm 99.9% sure it's a sensor issue and not a wire issue.

I'm debating weather to look for an aftermarket temperature sending unit I can actually see the correct temps with. I like to keep an eye on those things. Would I need two gages to monitor both banks of cylinder heads or would using just one temperature port be sufficient?

Anyone have a suggestion on a compatible temperature gage that would work in place of this sensor?

The tellttale seems to be working as it should but I have no idea when the impeller and other parts were last serviced. So figure it's good measure to just spend the $80 for the water pump kit and do the work myself then I know when it was last serviced.

 

[Fed]

Disconnect both sensors.
If the buzzing continues you have a wiring problem, find it & fix it.
If the buzzing stops you have a sensor problem, reconnect them one at a time & the one that activates the buzzer is faulty.
Replace the faulty sensor.

 

[interalian]

And if you want to monitor actual temperature, it's no trick to put a sensor on each head and connect them to one gauge using a SPDT switch. Typically the higher head is warmer, so I leave my switch set to that side. Automotive sensors can be found for reasonable prices but you need a low-range temp gauge as you're looking at ~140-160 as max working temp vs cars which are over 190.