No gas or oil line blockages- VRO horn still blows!

Jayboid

Seaman Apprentice
Joined
Jun 24, 2007
Messages
48
Hi,
I have a 1989 Johnson 150 outboard V6. I've changed the gas line filter and have disconnected the gas and oil lines at various points, squeezing the primer bulb to insure that there are no line restrictions. The VRO horn still blows steady above 2500 RPM and quits when you back off the speed to below 2000 RPMs. With the VRO horn disconnected, it will run a short while above 2500 RPM and then backs right off just as if you had pulled back on the accelerator handle.
The VRO detects excessive vacuum pressure in the input lines to the VRO unit. My oil and gas lines leading to the VRO unit are clear and without leaks. Could excessive vacuum also be caused be leaks or kinks in the ouput lines from the VRO to the 6 carbs? I see and smell gas from somewhere in there but havn't tracked down the source yet. My question: Can excessive vacuum pressure at the sensor (which is located prior to the VRO unit) be caused by something other than restricted filters/lines leading from the oil and gas tanks to the VRO unit?
Thanks,
John:confused:
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: No gas or oil line blockages- VRO horn still blows!

It could definitely be caused by a anti-siphon valve, but the bulb would be fairly soft if that is the cause. The anti-siphon valve is located within the outgoing hose connection on built-in fuel tanks.
 
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