Exhaust fumes

[Pha8]

After 5-7min of the engines running (Blowers turned on) exhaust fumes enter the aft cabin making the co2 detector and the fume detector in the helm go off? All the exhaust/blower hoses seem tight on their fittings unless I am missing something? Any ideas?


EDIT: Their are 2 switches for the blowers.
1 on the helm station
1 on the DC Main panel

Both have to be turned on??
Thought both switches would control all blowers?? Odd

[bud37]

Is this something that has just started ?

Not sure what is setting the engine room fume detector off.....be careful here as they ( the detectors ) look for explosives like gasoline fumes so again be very sure you do not have a fuel leak from engine fuel systems or fuel tanks although very high levels of CO are flammable. Check all your exhaust hoses all the way to the hull outlets for muskrat damage, you maybe would have water in the bilge from any leak like that though IMO.

As for the CO.....with the blowers and the engines running you are evacuating a lot of air from the engine room so you maybe getting a loop going that pulls exhaust back in thru the aft from outside with certain wind directions. Again be very careful here as CO can be a silent killer.

Check your engine room vents to be sure the inlet vents are clear and letting in fresh make up air.

It is good you are taking this serious.......good luck and be careful.

[Pha8]

Hey thanks Bud37

The boat is new to me. When I transported the boat 5hrs to its new home, both alarms were going off the whole time. I just replaced both impellers and ran each engine after replacing the impellers and both times, both alarms went off. No smell of gas, but I could smell exhaust fumes in the aft cabin. Blowers going and engine bay floor (Salon floor> 1 panel) open.

[km1125]

You might want to do a really good inspection of all your exhaust hose and mufflers (if any) to see if there's a compromise somewhere. If you're leaking exhaust right into the engine compartment or bilge, it will set off fume sensors and CO2 sensors.

And you can try to run one engine at a time to see if the issue is related only to that engine.

[waybomb]

How old are the sensors? Should be an expiration date on it somewhere. They only last so long.

[sbb2112]

Not sure of the layout of your boat but mine has a tag at the bottom of the windows that says they must be closed when engines are running. The CO2 alarms go off very soon after the windows are opened. It is the loop effect on mine as mentioned above.

[Rocketman]

You need to also make sure your salon floor hatch is closed. Not sure why you would want that open (if I am interpreting what you are saying correctly).
CO monitors are only good for about 10 years.
Check where your exhaust port is at relative to your blower input. I have seen where they are too close to each other and the intake pulls exhaust right back in.
If so, you may need to reverse that one (most boats have multiple blowers) to make it blow out instead of in. You are just trying to ventilate the compartment. One blowing in and one blowing out is sufficient to vent.