1988 Johnson 225 hp VRO Alarm

rose marie

Recruit
Joined
Jul 27, 2010
Messages
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I am getting a signal from the horn indicating no oil. I traced of the oil resevoir hoses and confirmed oil up and into the site tube. Short of replacing the VRO pump right off I need to perform some diagnostic tests. Does anyone know how many inches of vacum there should be at the vacum switch and is this switch normaly open or closed during operation. Does this switch sound the alarm or does it come from the VRO pump. Next the Pulse limiter switch may be clogged with carbon deposits and will cause a fuel or oil restriction as well. Can anyone give me any information that may be helpful towards solving this problem?
 

Incorrigible

Petty Officer 2nd Class
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Jan 5, 2009
Messages
111
Re: 1988 Johnson 225 hp VRO Alarm

Just to verify:

You're getting the alarm sound every second or two or are you getting the alarm sound every 30 seconds or so?
 

rose marie

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Jul 27, 2010
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Re: 1988 Johnson 225 hp VRO Alarm

Getting the alarm every second for a second which according to the book is a no oil condition. Since my post I removed the vacum switch and tested it with an ohms meter and it is working properly. Tomorrow I will test the vacum from the engine and I'm told that it should be 5-6 inches. If I have less or none my problem is much more serious than the VRO pump. If vacum tests good I probably have a bad VRO pump. I could not locate the pulse switch and was told it could not be purchased seperately and it was part of the VRO pump. I looked all over for it maybe someone can give me a hint where it is. It shows in the shop manual being off and cleaned for carbon deposits. Thanks for the response.
 

d.boat

Chief Petty Officer
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Sep 19, 2008
Messages
520
Re: 1988 Johnson 225 hp VRO Alarm

You could also try inspecting all oil lines and connections and then re-priming very thoroughly. Could be a tiny air leak or air bubble.
 

rose marie

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Jul 27, 2010
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Re: 1988 Johnson 225 hp VRO Alarm

I have oil all the way to the site tube. I disconnected the oil line at the site tube squeezed the oil primer bulb good steady flow without restriction. I will start the engine tomorrow using a 50:1 mix on the fuel side so the engine will not be damamged and try re-priming the oil to the VRO pump. Hopefully the engine will read 5-6 inches of vacum. I'm getting a bad feeling about the VRO pump. Still need to find where the pulse limiter screws into the crankcase. Any ideas on that? It cannot be more than 6.25 in. from the bottom of the VRO pump because the parts book shows how long the attaching hose is.
 

d.boat

Chief Petty Officer
Joined
Sep 19, 2008
Messages
520
Re: 1988 Johnson 225 hp VRO Alarm

...Still need to find where the pulse limiter screws into the crankcase. Any ideas on that? It cannot be more than 6.25 in. from the bottom of the VRO pump because the parts book shows how long the attaching hose is.

I really don't know how similar your '88 225 is to my '90 200, but I'd bet "pretty darn" :)

OK, I've been thinking and the only way I think I can help is to trace the pulse tube from the VRO/OMS pump back to the pulse limiter. Look at every hose that is connected to your VRO/OMS pump. There will be 4:

Gas In
Oil In
Fuel (gas/oil) out
Pulse fitting.

Look at the diagram on this website http://continuouswave.com/whaler/reference/VRO.html

The first three should be dead obvious, and therefore the fourth one is the pulse inlet.... trace this to the pulse limiter which should be screwed into the crankcase (like mine) or maybe inline (I don't think V6's are inline).

As the article points out, the "old" pulse limiters have a black face, the new ones are obviously blue metalic color. I don't have a photo, but again, if you trace the hose from the pump fitting to where it ends - that will be the pulse limiter. If yours isn't blue, it should be changed. I had to change it on my '90, so if you haven't had that done, I'll bet you need a new pulse limiter. If you're lucky, that's the entire problem. Wouldn't that be great? (PM me; I have an extra, brand new blue pulse limiter that I'll mail you free just to get it out of the "box of stuff"!)

Hope that helps.
 

rose marie

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Jul 27, 2010
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Re: 1988 Johnson 225 hp VRO Alarm

I appreciate all that good info and the offer of the pulse however I have definitely narrowed it down to the VRO pump. Good old ethenol fuel has ruined the diaphrams within the pump. The new VRO pump comes with the new pulse which ordered seperately cots about $26.00. Hey 22 years of service out that pump isn't bad. Thank you for all the help and the recomended site. I printed out all of the sites info on the VRO pump.
 
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