warning alarm bursts -- Why?

kameika · Aug 1, 2004

Hi folks, I'm wondering if you could shed light on a problem that came up last night.. I have a 1988 OMC Seadrive, 2.7 L. It does have VRO. Late yesterday evening, on the ride home, the oil/temp alarm began to ring. It was not a steady tone. It would start ~2 minutes after the engine started, and beep once every 2-3 seconds. My service manual states a steady tone for overheat and fuel restriction. It states a "burst" tone for low oil every 20 seconds. This alarm does not fit any of the descriptions. Also, the "pee" is strong (new pump in Spring), I have 3/4th oil tank fill.. The engine runs perfectly if you ignore the horn. (It got me home nicely..) Another weird thing: If I turn the engine off, then restart--silence for about 2-3 minutes. Then the beeping begins. Turn the key to off, and restart immediate--you get silence for another 2-3 minutes. Finally, if throttle is raised to 3000 rpm, the intermittent beep frequency rises. Do I have a faulty sensor? Could this be? Does anyone have a better explanation than a sensor?? Any help is appreciated! Regards, Ken Ameika Red Bank, NJ

Walker · Aug 1, 2004

Re: warning alarm bursts -- Why?

First put some oil in your gas 50/1 ratio. Then Unplug the VRO alarm, the tan wire, and just idle your motor and see if the alarm comes on. Sounds to me like you're getting a no oil alarm. Bad idea to continue to run a motor with an alarm sounding

kameika · Aug 1, 2004

Re: warning alarm bursts -- Why?

Well, I just went to the slip. I checked the oil/gas mixture at the VRO pump-all is good from the mixture output port. Also: Plenty of smoke. The alarm persists. After about two minutes, the alarm begins a 2-second tone after a ~2 second pause. Raise the engine RPM and the tempo increases. ..So I continued investigating.. More information: 1. I checked each warning sending unit individually. All, when shorted, operated properly. 2. I ran the engine for two minutes, and the alarm began to beep. I then disconnected each sending unit to find the bad guy. No dice. 3. Next, I pulled *all* sending units. The port thermostatic switch, the starboard thermostatic switch, the vacuum switch, the VRO tank switch--ALL taken off. The intermittent beeping did not stop. Question: Aside from the two thermostatic switches, the VRO tank warning device, and the Fuel/Oil pump vacuum sending unit--Is there one that I am missing? My shop manual says only those four devices will cause an alarm. Did I miss one? Could it be the alarm device itself? Thank you! Ken Ameika

CharlesW · Aug 1, 2004

Re: warning alarm bursts -- Why?

Walker gave you the first step to take. First put some oil in your gas 50/1 ratio. The alarm you are getting indicates no oil to the motor. By putting oil in your gas you may prevent serious damage to the motor. You may have already done that damage. I don't know anything about what sensors do what, but your alarm system is probably OK and trying to tell you the motor is not getting oil. IMO, running your motor without having the proper 50:1 gas to oil mixture is a big mistake.

kameika · Aug 1, 2004

Re: warning alarm bursts -- Why?

Understood. I did put oil directly into the fuel tank. No worries, I did take Walker's advice. Also, last night--to get back to port, the "Seadrive" manual states it is acceptable to run below 1500 rpm even without. This was a surprise to me. Okay--if the VRO pump is bad, would it normally go "dead bad," or would it run shortly, then fail? Have you seen a failure mechanism for such a thing? What baffles me is the following: How does the horn "know" there is a problem when I disconnect the vacuum sending unit? Is there another sending unit inside of the actual VRO? ..It does appear to run for a short while without complaint or horn.. Hence my question. Thank you again.. Ken

CharlesW · Aug 1, 2004

Re: warning alarm bursts -- Why?

Chances are the alarm has a time delay before it sounds. The VRO probably could fail in such a manner that it works, but not 100%. Make a mark on your oil tank and verify that the oil level is actually going down. The oil level going down would indicate to me that the VRO pump is working to some extent. There are procedures to check the proper VRO operation, but I'm notfamiliar with them. You also might want to budget about $270 for the new VRO fuel pump.

Walker · Aug 1, 2004

Re: warning alarm bursts -- Why?

I've replaced a few of them and the no oil alarm takes some time to go off every time I test one. If you disconnected all sensors and still have an alarm I'd expect the alarm buzzer is bad, but if so it should sound immediately with no delay.

kameika · Aug 1, 2004

Re: warning alarm bursts -- Why?

Walker, I think you're right. If I'm understanding you correctly, this does not sound like a failure of the VRO pump, yes? Like I said before, FOUR total sending units were disconnected (little tan wires..) Yet, something was making the alarm horn (it's more of aPiezo electric whistle, actually) pulse rapidly. My owners manual differs from my shop manual: The owner's manual does say this is a VRO alarm. Could there be another sending unit which goes into the VRO housing that I failed to test? Correct me if I'm wrong: But the VRO operates on engine vacuum. Right? Do you recall if there is a sensor inside of the VRO, or is only the oil pressure sensor just aft of the VRO assembly? And Charles--thank you for the information, too. I will try your suggestion ASAP with the marking of the tank. This is quite a mystery. I promise to tell you of the outcome. Many thanks for the patience! Ken

dacheedah · Aug 1, 2004

Re: warning alarm bursts -- Why?

I had the same problem only it was a faulty heat sensor, My motor has two, unplug one at a time while it's beeping and see if the beep goes away. If it does replace the sensor.

CharlesW · Aug 1, 2004

Re: warning alarm bursts -- Why?

Originally posted by Ken-Red Bank: If I'm understanding you correctly, this does not sound like a failure of the VRO pump, yes?

It sure sounds like a problem with oil delivery to the motor. Might be something wrong in the VRO system besides the pump not working. Loose fittings, bad oil line, lost its prime. etc. On a 1988, it wouldn't be too surprising to have the VRO pump fail. I just replaced mine on a 1986 40hp, not because the VRO failed, but because the fuel pump quit workng. Same $270.

Walker · Aug 1, 2004

Re: warning alarm bursts -- Why?

Depending on which way your VRO is mounted the oil alarm is in a small square electrical component on the face of the pump. Here's something you can do with an Ohm meter. Disconnect the tan wires and check for continuity between the tan wires in the wiring harness and the engine block. There should be no continuity. The alarm works by closing the ground side of the circuit. If you have continuity the disconnect the alarm buzzer and check again.

kameika · Aug 1, 2004

Re: warning alarm bursts -- Why?

dacheeda--did you have short bursts from your warning horn? Charles--I did check carefully all fittings to ensure against vacuum/etc leakage. I reasoned out this stuff operates under fairly exacting pressure, so I checked everywhere for leaks.. I'm with your advice.. CharlesW: I'm very willing to spend that $270.. Boy, I'd spend more than that to be sure no damage has been done to the powerhead. My boat is pretty old, but it is well preserved. Let me put it differently: If the boat goes kaput, the it would not be worth the money for a new powerhead. Catch22 is my wife would divorce me before I could get a new boat.. It may be worth it.

Walker: Please advise/confirm-- (I have a 1986 Service manual, I have a 1987 Seadrive I want to be certain I have it right--) The sending unit is a little cylinder with a square mounting body. Right? A single, nylon tube runs from this little sending unit to the outlet side of the fuel filter. The sending unit mounts to an aluminum flange via a locking washer thingie. On the VRO pump itself, there are no wires--only hoses. Correct? Again--Many thanks! Ken I'm wondering if the 1986 (service manual vintage) model VRO and the 1987 (engine vintage) have a small difference between VRO pumps..

Walker · Aug 1, 2004

Re: warning alarm bursts -- Why?

Ken, I think you are describing the fuel restriction sensor. The oil pump is part of the VRO and 3 to 4 inches diameter round, mounted on the port side just behind the carbs or on the prot side just in front of the starter. There will be a 3 or 4 wire connector going to it. The tan (alarm) wire to the oil pump is in that group.

kameika · Aug 1, 2004

Re: warning alarm bursts -- Why?

Walker, then you've identified a difference between my 1986 service manual and the actual 1987 engine assembly. I did not notice there was a sending unit to that VRO pump. So, I will take back what I said earlier: I did *not* take off all sending units. There is a sending unit within the VRO, in addition to the fuel starvation sensor. That is, there are FIVE warning horn wires: #1, #2: 2 thermostatic (temp) switchs on the heads #3: 1 vacuum (fuel starvation) sensor #4: VRO tank float sensor ..and #5: VRO pump oil pressure sensor Yes? One last question: If the system were oil-starved, I would see very little smoke in the exhaust. True? Do you have any recommendations for an on-line OMC parts retailer? Ken

Walker · Aug 1, 2004

Re: warning alarm bursts -- Why?

Ken, smoke from the exhaust it hard to judge. I can't say for sure you won't see any smoke if you are lean on oil. You probably don't have a complete pump failure. There should be a pencil thin inline oil filter just before the VRO. Might want to try cleaning or replacing it. Could be your problem, hopefully.

kameika · Aug 1, 2004

Re: warning alarm bursts -- Why?

'Just took a bike ride to the marina. You're right on both accounts: 1. There is a pencil-thin filter. I did not know this was a filter. (Another '86 to '87 model year difference?) 2. There is a tan wire, which was not accounted for. You make an insightful comment: The problem does appear to be something like oil starvation. A moment of "off ignition" will allow for the filter to "recharge." Also, running the engine at a higher RPM causes the alarm to sound sooner. I'll check this before running out to buy a new pump. You have some excellent insights, Walker. Are you in the industry? Ken

Walker · Aug 1, 2004

Re: warning alarm bursts -- Why?

Not exactly. I'm a professional firefighter, but I've been messing with outboards, mainly OMC for about 20 years. Got my start and some good experience working part time at a little shop with one darn good mechanic. My biggest problem now is I just don't have as good a memory as I used to.

kameika · Aug 1, 2004

Re: warning alarm bursts -- Why?

Walker, If firefighting turns out to not be your bag, consider going into the OB repair business.. Read on: You're on to something. I got inspired to go back to the marina. Maybe it was the cigar that I am forbidden from smoking in the house.. Anyhow, I pulled-off the oil feed line from the in-line filter plus the hose to the VRO pump. 1. 'Seems like there is not a filter element in the pencil-width in-line filter. Hmm. Where did the filter element go?? 2. The little hose from the filter to the VRO pump was in bad shape.. Despite not seeing a filter element, I blew out the parts with WD40, then re-fitted onto the engine. Next, I pressured the oil feed with the bulb--all the while, watching the little filter as if it were a watch-glass. When filled blue, I turned the engine over. After FIVE minutes--no alarm. I even checked the other sensors by shorting them.. The horn is working, but no alarm from the VRO. Ahhh. Here's the big question: Is it fixed? I'll have to sea-trial the machine. All I can say is that five minutes is far longer than it has ever run before. ..And I do wonder what happened with the filter element? Could it be caught-up in the pump somewhere? What's your opinion from here? How would you approach it, Walker? ..Rest easy though: You correctly diagnosed the problem while sitting at your computer. This is the "mop up operation." Thank you, Ken

Walker · Aug 1, 2004

Re: warning alarm bursts -- Why?

Well, I guess I'm not so smart after all. I just went out and pulled on off a 175 and it appears its just a sight glass, no filter. But it is possible that your oil pump had lost its prime and after you pumped it back up you cured it. Take Charles' advice and run premix and and mark the oil level on your tank to be sure the VRO is pumping oil.

CharlesW · Aug 1, 2004

Re: warning alarm bursts -- Why?

Walker: It is just a sight glass, not a filter. A couple of things. 1. The primer bulb on the oil line may require a lot of squeezes before you have good oil flow. When I first bought my motor, (used), I disconnected the oil line at the motor to be sure I had the lines bled before I tried to start the motor. It must have taken 20 to 30 squeezes before I felt I had enough oil flow to be comfortable with. 2. The "run pre-mix and mark the oil tank" suggestion really isn't mine.

It was suggested to me a year or so ago by someone on this forum. Charles

warning alarm bursts -- Why?

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