4.3 OMC "making oil" Oil level keeps rising

Some of you may remember my previous question about what to do with a cracked block. I JB welded it and it seems to be working good. I'm confident that there is no water in the oil because it has not been milky either time that I drained it.

My current problem is that the oil level keeps rising. THe first time I noticed this, I bought a carb rebuild kit and rebuilt the carb. No change. Second try was the fuel pump. No change. Oil level keeps rising significantly.

I read through some of the articles about 4 stroke outboards "making oil". My engine gets up to 175 degrees or so regularly when I'm out boating but its inconsistant because of a lot fo stop and go.

One clue might be that the engine dies if I hammer the throttle down. Originally I thought that might be an advance problem with the dizzy but I've checked it out. The weights move freely and there is no rust or corosion inside it. My second thought was the the accelerator pump might not be working but that was eliminated as an issue during the carb rebuild. I've checked it since then and the pump is working fine. Possbily too good? At this point, I'm of the belief that its flooding out when I hammer down. That could cause fuel in the oil right?

Incidently, I carefully set the float level when rebuilding the carb.

So, what are the causes of an inboard V6 "making oil" via fuel in the oil other than a fuel pump and the common things that would be taken care of with a carb rebuild?

I think the only thing that I read but haven't checked might be the choke.

I'm stumped!

Chass
ct

Re: 4.3 OMC "making oil" Oil level keeps rising

What does the oil you drain out look/smell like....................and how much of an increase in volume are we talking about??.................a pint, a quart..................more??

Re: 4.3 OMC "making oil" Oil level keeps rising

Maybe it just wants to do its part in this so-called "war on terror"?

If it's not milky, it's almost definitely gas (does it smell like gas?). Are you positive you've got a good diaphragm in the fuel pump? It's unlikely to get a bad pump as a replacement, but it's happened before!

Re: 4.3 OMC "making oil" Oil level keeps rising

The oil that I have drained doesn't smell particularly strong of gas. Thats what caused me to have concern that maybe it was taking on water somehow but every time I drain it, the oil is NOT milky. The first time it was quite black even though the oil on the dip stick looked like new oil. There clearly isn't any exchange in the dip stick tube. The second time it was a little dark but looked like the newer oil that it was.

The oil level has risen almost an inch on the dip stick since the last oil change. That makes me believe that it was about a quart plus over full. We spent two days on the lake but only ran it a few hours. I probably burned 20 gallons of fuel.

I highly doubt its the fuel pump for two reasons. 1) It exibits the same oil level rise as it did before the new fuel pump. 2) marine fuel pumps are supposed to pump the fuel through the hose outlet at ther base up into the carb if their main diaphram goes bad. Neither pump was doing this.

I just read something about a stuck choke causing this. I'll take a closer look at my choke next time I'm out. I did adjust it when I did the carb rebuild but the plastic cover is damaged and it could be operating improperly. It did work fine on a warm up with the muffs on.

Oil changes are hard enough as it is. It sucks to have to do an oil change every time I go boating!

I guess I've checked all the obvious things . . . I was hoping someone might know an obvious issue with the older OMC Cobra 4.3s and fuel delivery that I may have missed.

Chass
ct

Re: 4.3 OMC "making oil" Oil level keeps rising

Well, hopefully the choke fixes it for you. Generally a stuck choke valve will cause you to run rich, but not enough to get fuel in the oil.

Is the level rising during use (ie, while you run it, it gets higher)? Or is it doing it while it sits?

Re: 4.3 OMC "making oil" Oil level keeps rising

Do you actually measure the amount of oil that you are draining out each time? Are you putting back in the same amount that you drained out?