oil/gas mix in the in line filter b4 the vro pump

hydra

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Joined
Oct 7, 2009
Messages
10
i have2000 200hp johnson and have had the check engine light on so i was checking the lines and as i was i noticed the gas and oil were mixed in the in line fuel filter.
i was wondering if this is a sign of a vro pump issue?check valve issue?
thanks
hydra
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,030
Re: oil/gas mix in the in line filter b4 the vro pump

Your motor should have a vapor pump, between the inline filter and the OMS pump. There should be no way for oil/gas to backup thru the vapor pump to the fuel line.

Are you sure there is no oil in the fuel tank? Did a PO mess with the OMS system?
 

kenmyfam

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Aug 10, 2006
Messages
14,385
Re: oil/gas mix in the in line filter b4 the vro pump

Agree, should not happen.
 

hydra

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Oct 7, 2009
Messages
10
Re: oil/gas mix in the in line filter b4 the vro pump

i have not heard the term OMS pump.i did have a repair to the primer pump. the cover cracked and we replaced the diaphram and cover.there is no oil in the tank ,the in line filter has clean gas when emptied and refilled.
what could fail and allow the mix the exit the system and enter the inline filter? could this type of issue cause the light to come on?
 

Chris1956

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Mar 25, 2004
Messages
27,030
Re: oil/gas mix in the in line filter b4 the vro pump

Oil Metering System (OMS) Pump is the proper term for the pump used to mix the gasoline and oil on your year 2000 motor. The Primer is downstream of the OMS pump, and should have no bearing on the problem.

The vapor pump pulls straight gasoline from the fuel tank and supplies it to the OMS pump for mixing. Since the vapor pump has a float and needle, there should be no way for the mixed fuel to exit the OMS pump thru the "gasoline in" fitting, and get past the vapor pump inlet needle.

Your issue is difficult to diagnose....
 

hydra

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Joined
Oct 7, 2009
Messages
10
Re: oil/gas mix in the in line filter b4 the vro pump

thanks for the reply. i have read some more on the subject,but i have not found an explanation for the fuel mix escaping. i will confirm this problem. are there check valves in place that could be clogged allowing mix out and causing it to run lean when operational?
hydra
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: oil/gas mix in the in line filter b4 the vro pump

There are check valves on the OMS pump. I am not sure how serviceable they are
 
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