1994 Mercury oil injection?
 

I just bought a 1994 Mercury 150. Is the oil in the reservoir tank injected directly into the engine? So that if I run the engine off of a 6 gallon tank I don't have to pre-mix? Thanks.

The oil in the tank under the cowling gravity flows to the oil pump. If you just bought it, i'd confirm the po didn't disconnect anything to bypass the oil injection. Just to make sure, i'd premix your pony tank at 50-1. Shouldn't hurt it to double oil it.

Edit: you didn't say if it was carbed or fuel injected

phatdaddy, Thanks for the input. The oil injection system is still operational,so I should be okay to just have gas in the 6 gallon tank it sounds like. You catchin any Spanish?

Different companies use different systems. On your engine the oil is mixed with the gas just before it goes into the carbs. Set up an aux tank with 50 to 1 mix. Look on the port side of the engine, you'll see the oil pump . look for the hose coming out of the pump that "t"s with the gas line near the bottom port side. Disconnect the oil hose from the "t" and put it into a small container. Start your engine running on the premix, and observe the hose you just disconnected. If your engine VRO is working properly you'll see about 6 drops of oil (or more) per minute while your engine is idling around 1000 rpm. No oil drip = bad.

Until you know it works, run it on pre mix. That system was very problematic to say the least. Many a Merc has died because of thst system and all the problems it had. And many times the alarm won't even go off when its messing up.

Caught one last week while trolling for grouper. Not really targeting them right now, trying to find a pompano. Been a real slow fishing fall so far. It finally cooled down.

How bout over your way?

Mine gave up that stupid nylon drive gear right in the Long Beach harbor over a dozen years ago. Had it neutered the next week & it's still running strong.

I'm still using my oil injection 1988 150 mercury No problems maybe I should keep my mouth shut I did have some issues one issue was there's a valve on the engine I think it's a check valve it would load up with oil and could not start the engine I changed the two valves Problem solved I would like to bypass it for safety reasons but I keep putting it off It runs fines What you can also do which I have done is while the engine is running loosen the cap on the oil tank that's on the engine and you should push out any air in there and then the oil should start to overflow Then you know it's working, the tank on the engine should be full

That only tells you if the crankcase check valve is good and pressurizing the supply tank. The actual oil injection pump can still fail, no alarm sound, and bye bye engine. Mercury actually used a good system, but cheaped out on the 2.0/2.5l engines and used that nylon clamshell drive gear. Suzuki, yamaha, and the bigger Mercs all used a bronze crank gear, and they were very reliable systems.

I was warned about that drive gear when I bought the boat. Pretty much ignored the guy, wouldn't you know it, he was in the boat when the gear gave out!