mercury oil injection

**whipper** · 03-27-2015, 10:54 PM

Originally Posted by Dave Strong

The other thing people don't understand you idle for 10-15min the VST s full of 90-80 :1 oil mix. Hammer it after idling and your running on idle oil mix till the VST refills.

Dave

Thats a very good point most people never talk about.

**tlwjkw** · 03-27-2015, 11:38 PM

mixture actually starts richen tha instant ya get on tha gas and float drops so its justa a few seconds at a very lean spot.....not enough ta hurt a healthy motor.

**David - WI** · 03-28-2015, 02:39 PM

There really isn't even a "lean" spot. The oil "ratio" isn't what really matters, it's the "amount" of oil in the crankcase at any given moment that matters.

With pre-mix, the amount of oil in the crankcase builds up at low rpm and it gets depleted at high rpm; so the changing ratios of the oil injection system are really just maintaining what you could call the "oil level" in the crankcase.

What is this oil migration time? The oil migration time is the time it takes the oil that is mixed in your gas to go from your carburetor through the crankcase and out the exhaust port. The lower the rpm (revolutions per minute) range of your engine, the longer some of the oil remains in your engine and the less oil you will need in your gas mixture. The size of your engine, the velocity (speed of the air) through your engine and the amount of sustained full throttle usage required for your application determines the oil migration time through your engine.

http://www.tlr-online.com/yahoo_site....61180056.html

In other words, the oil that's in the fuel isn't what's lubricating the engine, the residual oil left in the crankcase after the fuel evaporates is what lubricates the engine... the incoming fuel/oil mix just replenishes the oil supply in the crankcase as it evaporates. So, there's plenty of time for oil injection system to "catch up" when you go WOT.