VRO water sensor

So after changing the tstat cleaning the carbs, and re installing them correctly, I decided to take the boat out for a test run. I unloaded the boat, cranked her up, putted over to the dock, and let her idle while parking the truck, and returning to the boat. Upon returning, I idled out of the no wake zone, probably 10 minutes worth of idle time all in all. I pushed the throttle down, got on plane for a few seconds and the stupid alarm goes off for about 30 seconds, and the water temp light was on, and didn't go off. I immediately killed the engine. I may have waited 5 mins then cranked her up again. I hit the throttle again, she planed out, and the alarm and light come on again, just like last time. I waited maybe 5 mins again, and did the same thing, same thing again. This time I didn't kill the motor when the alarm stopped. Apparently the vro also puts the motor in limp mode. so I idled back towards the dock. The alarm only went off for about an eternity of 30 seconds, but the water temp light stayed on for a minute or two, then it went off. I idled back to the dock, dicked around with the idle screws on the carb, backed the trailer in, and loaded the boat, all without cutting the engine. All in all it had probably been 15 mins since the water alarm light went off, and nothing.


Like the great mechanic I am, I check the water temp at the pisser, while the alarm was ringing, and it was warm like a nice shower temp, but not to hot. I never put my hand on the head though ](*,). The fact that the alarm and light went off and I idled around for 15 mins without a problem leads me to believe the sensor is the issue, not the motor. Any insight on this would be very helpful. I am taking a trip to the coast next weekend, and need to get the running right so we don't have any issues. I can only imagine what my wife would be saying if we ran into issues while we are out in the bay. Thanks again guys, sorry for rambling.

What EXACT motor age and horsepower? When was the last time the waterpump/impeller/thermostat service was done? If you don't know ... do it. But DO NOT run the motor like you did.

Facts
-VROs do NOT have water sensors ...

-You should be able to place the palm of your hand on a head if not in overheat ... but do not burn yourself, as it ain't on me ...

Typical OMC Alarms
-Continuous alarm or beep means either an overheat condition or a fuel restriction

-Continuous beeping every 1/2 second or so = NO OIL

-Single beep every 20 seconds = low oil

On OMCs, the "hot" alarm circuitry can be shared with the fuel restriction alarm circuitry, usually on the larger motors ... but I don't know what you have (please, please provide such KEY details whenever asking for help ...), but it doesn't trigger the slow mode.

But it sounds like you are indeed having a hot alarm event, as that sensor tripping will trigger the SLOW mode, if an OMC motor. SLOW = Speed Limiting Overheat Warning. The sensors close to ground (tan wire w/ blue stripe, where 'tan' are sensors & 'blue' indicates cooling) when triggered at 240-degrees, if I recall correctly. The OEM test script is attached.

To test sensors (however, your's appears to be working) you pull apart the sensor 2-part connector and ground the wire side coming from the powerpack to ground, with the motor OFF but key switch to ON - where the warning horn will sound.

It’s a 1997 E40tleuc. I changed the thermostat and water pump this weekend. So why would the alarm sound only at wot then shut off a few minutes later and not overheat again while in neutral. Could it be fuel restriction, since it only happens at wot?


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You're all over the place ... did or did not the OB go into SLOW mode? If YES, that is the overheat alarm, not fuel restriction. I don't believe their is a vacuum switch for fuel pressure (vacuum really) on a 40hp motor.

Perhaps the temp sensor could be faulty ...

Do you have access to a temp laser to read head temps? Such lasers can be had for $20 or so.

Sorry for being all over the place. Yes it went to slow mode (like it had a rev limiter bumping max rpms). I will get a laser sensor, and test today or tomorrow to see what happens. I just don’t understand why a motor would over heat at wot, and not over heat at idle speed. I hope it’s just a bad sensor, that should be an easy fix.


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Over-temp at higher speeds, to me, would indicate a blockage in the head. T-stat opens @ higher RPMs to allow ‘full flow’, but sounds like your flow may be impeded.

Trace pee port line from cowling back to block. Carefully remove line. Any crud at the nipple there? Once had a 6hp with head blockage from salt build up that I took off powerhead (much easier to do on a 6 vs a 40) turned head upside-down and filled w/ vinegar for 3-days. Emptied head by compressed air, then reassembled and it ran like a charm.

I went through all of that when I changed the water pump and the tstat. Pulled the water case cleaned all the debris out. Water is coming out at the tstat, checked it. Strong water at the tale-tell. I’m heading to get a thermometer today, and gonna run her again to get a reading.


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You might have to tie her down well at a dock ... be careful, and I’d have someone with you w/one hand on the throttle and the other on the kill lanyard. This is where a test wheel is ideal, but only dealers have them.

Look up on-line, some claim that they test their temp sensors using heat guns, w/ motor off but ignition on.

My dad has a 40 acre lake in his neighborhood u can run gas powered motors in. I’ll run her in it, idle to one side and wot back. It will be plenty of room to do what I need to do. Then the tm can do the work if need be.


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Shmelton said:

My dad has a 40 acre lake in his neighborhood u can run gas powered motors in. I’ll run her in it, idle to one side and wot back. It will be plenty of room to do what I need to do. Then the tm can do the work if need be.


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Click to expand...

You can also back it in with it tied down to the trailer if the ramp is deep enough and leave it hooked to the truck if you have a private ramp on this lake. You can put it in gear and advance your throttle on up to make sure it is well tied to the boat first then get it open. That will work the motor harder actually than you can at WOT running across the lake. If it is going to heat it will then.

Pappy said:

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You mentioned you knew you had water at the thermostat.....how did you check this?
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If I’m getting water in the water case, I’m getting it to the thermostat right? Im also pretty sure when I was working on water pump issues I pulled the tstat cover to make sure water was making it there.

I will be the 1st to admit I don’t know a ton about an outboard motor. But, I am not intimidated by them either. This is the 1st outboard I have ever worked on. I hope to learn as much as I can about them. I have worked on mud motors for years, but because they are air cooled engines, I have never had to deal with issues like this. I really appreciate the input you guys are giving, and I hope to learn a lot from this forum. Maybe I can even give a little advise on day.

Thanks
Nick


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I’m going to get a laser reading today hopefully. My wife has one of those stupid “31” parties to go to this evening. Hopefully I can get home from work in time to get the boat in the water before she goes.


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Got the laser out, and it was over heating. I pulled the tstat and a bunch of crud had built up around it. I cleaned that out. Cranked up the motor with the tstat out and the tstat cover off ran it for about 30 seconds. Put the tstat back in and she is cooling at a nice 145 degrees.

I’m sure I wasn’t supposed to run the motor without the tstat housing in, but there was so much gunk in there that was the only way I was gettin it out.


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Water temp is 86 degrees, I got 3 temps at 103, and 1 temp at 145 within a few seconds. I figured 103 was off like I was lasering the plug wire, but I guess it was right. Not sure where 145 came from just assumed it was right. I guess all is well know. I’m going to pull the tstat cover again today and see if there is more build up. If so I’m going to flush it.


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Shmelton said:

Water temp is 86 degrees, I got 3 temps at 103, and 1 temp at 145 within a few seconds. I figured 103 was off like I was lasering the plug wire, but I guess it was right. Not sure where 145 came from just assumed it was right. I guess all is well know. I’m going to pull the tstat cover again today and see if there is more build up. If so I’m going to flush it.


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Click to expand...

And once again.....At what RPM were your measurements taken?
We do like information around here in order to help you! I never graduated my mind reading course, didn't like what was in the instructor's head.

I don’t have a tach but it was at wot. I’ve got a tiny tach in the shop I may put on today. Sorry I didn’t included that info earlier.


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