flboatmanbay
Recruit
- Joined
- Apr 15, 2023
- Messages
- 4
So I have a 5.0L Mercruiser 2005. It got a lot of use up to about 4 years ago and has been sitting ever since. I took the opportunity to do some much need maintenance. I replaced the exhaust manifolds and elbows, rebuilt the carb, rebuilt the trim cylinders, changed the oil, spark plugs, wires, fuel/water filter, fuel pump (was bad), and I think that's about it.
The challenge I'm having is that it's smoking still. It was smoking before (4-5 years ago) as well, worse when you first start it and gets better as it warms up but still smokes some. I did a compression test and 6 of the cylinders were around 190 psi and 2 of them were at 150 psi. Although I know it's not ideal to see a difference like that, it's still 150 psi which seems plenty high and doesn't make me think it's a head gasket. I've tried adjusting the fuel mixture screw on the carb after rebuilding but doesn't seem to make a difference. Doesn't seem like it does much of anything. I can bottom it out and have really no noticeable change in idle and out 6+ turns and still no change so I set it at about 1.5 turns from bottom as they recommend for a starting point. Anything else that might cause smoke? It smells a little rich.
The other thing I noticed that concerns me is that one exhaust elbow is very hot after running (right manifold in pic below) and the other one is cool as a cucumber (left manifold). It looks like I'm getting exhaust water off both sides of the outdrive and through the prop so it seems like it's getting water through both sides but I don't know if it's one side if it will still come out all 3 places. What could the issues be? Any input welcome. Thanks!
The challenge I'm having is that it's smoking still. It was smoking before (4-5 years ago) as well, worse when you first start it and gets better as it warms up but still smokes some. I did a compression test and 6 of the cylinders were around 190 psi and 2 of them were at 150 psi. Although I know it's not ideal to see a difference like that, it's still 150 psi which seems plenty high and doesn't make me think it's a head gasket. I've tried adjusting the fuel mixture screw on the carb after rebuilding but doesn't seem to make a difference. Doesn't seem like it does much of anything. I can bottom it out and have really no noticeable change in idle and out 6+ turns and still no change so I set it at about 1.5 turns from bottom as they recommend for a starting point. Anything else that might cause smoke? It smells a little rich.
The other thing I noticed that concerns me is that one exhaust elbow is very hot after running (right manifold in pic below) and the other one is cool as a cucumber (left manifold). It looks like I'm getting exhaust water off both sides of the outdrive and through the prop so it seems like it's getting water through both sides but I don't know if it's one side if it will still come out all 3 places. What could the issues be? Any input welcome. Thanks!
