Logo
FULL SITE MENU

Strong crankcase smell / how to clean engine room

S

Silver(ton)Surfer

New member
Hi,

Our new to us 1988 Silverton 40 Aft Cabin is equipped with twin, carbureted Crusader 350 engines.

After sitting for a while, it develops a strong crankcase smell in the cabin. What I mean by that is the typical smell that you get when you open the oil filler of a hot engine, which consists of blow-by and hot oil.
We believe that part of it is now actually coming from the carpet and the furniture as this issue has probably already been going on for some time.
When I’m sniffing around the engine room, everything seems pretty much dry and I struggle to locate any specific source for it. In fact, the only area where I am noticing the same small is at the flame arrestor, where the crank case vents end. I am also noticing a distinct gasoline smell in this area.

I guess some of it is normal for an old boat with carburated engines. Still, I have a few question, which I hope somebody will be able to answer:

- What is a good way to clean the eninge without polluting the environment? I am aware that there are dedicated cleaners but would you hose the engines down and can I avoid that the nasty water / oil / cleaner mix gets in the water?
- What about the strong odor that seems to originate for the carbs and the crankcase vents? Is this normal? Is there something I can do about it?
- When you get back to your boat after a few weeks, does it also have a very strong odor of hot oil / combustion byproducts in the cabin?

Oliver
 
If you have a strong odor , (engine, oil/gas), it would appear that you have a leak between the engine compartment and the living area. There should not be any engine smell entering the living area. Possibility that your engine room vents are blocked and engine odor is not leaving the boat. I'm sure you are aware that the "blowers" should be on when starting and when at idle, or very low power to ensure fumes are leaving the engine room. I have 4 outflow vents and two inflow vents on the deck of my vessel.

Either way.....the odor at the carb and flame arrester is normal, there is residual gas in the carb when you shut down. The crank case vents should be attached to the flame arrester so there could be a bit of a smell there too but not enough to permeate the living area.

I have twin 350s in a 1991 boat and the engine room is secure and all wires leaving the engine room have gaskets on the firewall.
 
willow said:
If you have a strong odor , (engine, oil/gas), it would appear that you have a leak between the engine compartment and the living area. There should not be any engine smell entering the living area. Possibility that your engine room vents are blocked and engine odor is not leaving the boat. I'm sure you are aware that the "blowers" should be on when starting and when at idle, or very low power to ensure fumes are leaving the engine room. I have 4 outflow vents and two inflow vents on the deck of my vessel.

Either way.....the odor at the carb and flame arrester is normal, there is residual gas in the carb when you shut down. The crank case vents should be attached to the flame arrester so there could be a bit of a smell there too but not enough to permeate the living area.

I have twin 350s in a 1991 boat and the engine room is secure and all wires leaving the engine room have gaskets on the firewall.
Click to expand...

That's an interesting thought I hadn't even considered yet. Frankly, the smell in the cabin is worse than in the engine room, after the boat has been sitting for a few days.

We turn the fans on a few minutes before we start the engine and leave them running until at least 20 minutes after we shut them down. The access hatches don't have any seals on them but they are wrapped in carpet and fit very snugly. I need to check if there are any other openings between the engine room and the cabin. From what I can tell, the engine room vents are open.

I spoke today with the boat yard, they will check out the issue. While I'm a car and engine guy, I don't have any big boat experience and therefore decided to bring in the pros.
 
Back
Top