Unhooking Oil Injection On 200 Merc Carb

[DC Foor]

What is involved in unhooking the oil injection on my 99 200 Merc carb

[capnzee]

I am sure there will be many answers following this one, but I think you can just start adding oil to the gas at 50:1 or if you are going to turn over 6000 you may want to mix it at about 42:1. You can take the oil pump drive gear out and buy a seal/cover from Merc or you can make your own. Then you can take all of the hoses, tank, and associated paraphanelia off if you want. You can take the engine apart and remove the drive disc (for lack of a better name). I left the stuff on my engine in case I sold it and the guy wanted to go back to the oil pump system. I don't know if this is the right thing to do but I have not had a problem. I do mix the oil on the heavy side. OK guys, tell me I'm looking for trouble! Gone fish'n capnzee

[aalbert]

I have a FAQ at http://www.biggerhammer.net/mercury/ that I compiled from sifting through a lot of posts from screamandfly.com .... Here is the cliffnote version

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The mercury oil injection system is a popular item to remove, especially given its reputation for failure, and inability to deliver reliably after 6500 rpm.

Remove oil resevoir, oil pump, mag pickup, pump drive shaft, then install plug in shaft hole. Remove oil hose off bottom of vapor seperator, plug hose, remove fitting on starboard side of the block where oil tank pressure hose is coming from, plug hole with pipe fitting either 1/8 or 1/4., Remove oil alarm box, and i think that's all. the plug for the pump shaft hole you will have to get from dealer. (12)

Mercury part number for the plastic block off plate is 43453 and the O-ring for that kit is 32509. Jay Smith Racing Engines also has a billet kit for doing this.

Finally it is recommended by several sources, that you keep the old oil pump gear on the crankshaft, as it provides crankcase volume, and if removed will cause that cylinder to be lean.