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Evinrude 90hp VRO oil buzzer only at idle

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Evinrude90

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Hello expert...I have been struggling to figure this issue out for a while now, and can't seem to get a good lead on it.

The issues: My 1988 Evinrude 90hp throws an alarm (buzzer) for low oil flow but only at very low load and idle. No issues at mid to high load/idle. It is a beep that comes on for 2 seconds and off for 2 seconds, with increasing frequency as the RPM's go up.

I have done a few test, and it seems like the VRO oil pump work fine. Last night I filled a 12" long clear hose (3/8" diameter) with oil, and connected it to the oil inlet on the VRO pump. The engine seems to be pulling oil out from the clear hoes, as it is obvious that the level is dropping.

The above procedure was found here: http://www.boatpartstore.com/vro.asp

Although I was not sure what they mean by "monitor the pump cycles by using a fuel pressure gauge or by putting light finger pressure on the outlet hose."

Not sure what they mean by "put light finger pressure on outlet hose". What outlet hose?

I have taken the oil reservoir out, and pulled the entire pick-up out. The screen is nice and clean. The oil priming bulb is hard when everything is connected to the engine while it is running.

Any input would be greatly appreciated.
 
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I should mention that when I did the clear hose oil consumption test, the alarm did not come on. This adds to the confusion, since the system monitors pump pulses, and not the actual pump flow/consumption.
 
flyingscott said:
Could be a bad sensor. Is it the original pump
Click to expand...

I thought about the sensor, but it all seemed fine when I had the clear line hooked up for oil consumption monitoring. I believe it is the original pump. I took it apart, and everything inside look brand new. No holes on the diaphragms, all O-rings look great, and no signs of lost elasticity.

The sensor also measured 1k ohm to between pins B and C.
 
the sensor is on the backside of the oil pump and I believe is not serviceable. I have had them go bad and testing the pump for oil draw is a certain amt of oil drops a specific amount in the tube not just does it drop. What does your pulse line look like is it in good shape. What kind of clamps do you have on the hoses really should be oetiker clamps
 
I understand that the oil consumption would have to be metered in order to perform a trued diagnosis, but I am unsure of how the pulse count is taken. The pulse line looks good, and the clamps used are the ratchet type, as recommended by the manufacturer. I also have some T-bolt clamp style hose clamps for this application, as my experience with the plastic ratchet clamps is that they can break when being removed.

s-l225.jpg


Ratchet-Hose-Clamp.png
 
flyingscott said:
What kind of condition is the fuel line in I never use the plastic clamps because they break or pop off over time.
Click to expand...

It appears to be in good shape, bUT I will replace it it in the next day or two. I'll also be on the water in 3 days, so I'll keep a very close eye on the oil tank level. It was filled to the cap, so I'll kow if oil is being injected. I have added oil to the gas tank for safety.
 
Thought I report back on this.

Went out, got the boat in the water. Alarm started rather quickly, even at higher RPM'S, which was not a problem last year. As I had brought hoses with me to the lake for the week I figure I might as well get going with changing those.


First thing was the crank case pressure hose which drives the air motor. I went to remove the clamp on the engine side (plastic ratchet type) and the issue was very evident right away. The clamp, even though it looked good was sheared on the back side of the ratchet. There was no way to see it. I put a new clamp and went out to see how it runs.

No issues at all. No alarms, nothing, not even at idle.

So this thing was broken from the get go. It just wasn't evident because the leak was not big enough to cause issues when wide open. With me tinkering with it before going out, I must have made it worse, which in tern caused issues when I went out at higher RPM'S.

The motor pulls oil from the reservoir as I have monitored it through the 80L that I burned on this trip.

So to sum it up, all is well.
 
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