How does disabling the oil injection on a 1989 mercury outboard affect the engine?

Question

How does the oil injection work on an 1989 mercury 200 hp? Does it change the amount of oil being injected with different rpm's?

Answer 1

Yes it increases the oil to fuel ratio as the rpms increase.  Without going to the books, the ratio at idle is approx 110:1, while at wot the ratio is around 50:1.  This significantly reduces the amount of emissions.  Theses oil pumps have been known to fail under severe conditions, so most performance boaters disable the pump and run mixed fuel at 50:1 to prevent the chance of catastrophic failure.

Answer 2

I'm not sure how it regulates how much oil is being injected, but if you disable it, then you will have to mix your oil and gas.

Answer 3

I'm surprised to learn that mercs had variable ratio oiling...I thought that was just OMC, and they abandoned VRO, what was it, early 90's in favor of the OMS (oil metering system)?

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