evinrude too rich?

[clayfish]

I had to get a new (refurbished) lower unit for my 77 15hp evinrude and when testing yesterday I noticed something. I put it on the muffs and ran for a good 10 minutes then I wanted to see just how much water the pump would put out so I Put it in a trash can full of water and ran it a while. I put it in forward and reverse and everything went well. When I took it out of the water I noticed a good amount of brown almost frothy oil in and around the prop housing. It smelled pretty gassy. I also had alot of smoke while I was running it. Is the new unit already leaking? Is this just unburned oil and gas in the exhaust from running too rich? I'm just not sure. I didn't think to take a picture.

 

[clayfish]

I just drained the gear lube and water is not getting in to the case. i just don't understand why there would be so much burnt oil coming from the prop exhaust.

 

[bassboy1]

What fuel/oil mix are you running it at? It should be at 50:1.

In the tank, you spent most of the time idling as well, correct? If so, it is just unburned oil and carbon. That is just the nature of these older 2 strokes. The bigger motors that have VRO/OMS (Variable Ratio Oiler/Oil Mixing System) pumps will give the motor less oil when idling, but on motors you premix, the ratio is constant, and the motor compensates by spitting it out down there.

Here is a picture of some of the unburned oil exiting my 1988 Evinrude 4 deluxe once.

You should probably run some Seafoam through it. Sometimes increased smokiness, as well as the noticeable amounts of unburned oil are evident of carbon buildup in the engine. Seafoam helps burn away that carbon.

 

[clayfish]

I'm running 50:1 and most of it was spent idling. The oil looks very similar to that so I'm good. Thanks.