Fuel smell when A/C on

D

Dan Kozusko

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Joined
Oct 11, 2007
RO Number
28781
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108
I wonder if anyone has had this problem with a late 88-92 30foot Santego.When I run my A/c while docked, eventually it picks up the bilge and fuel smell. My unit sits under the forward berth in a compartment that is open to the front bilge. Other boats like mine have it in the salon under the bench and have no problems. The evaporator is not directly connected to the intake vent and is only close (5-6"). Should I duct it or try to move the unit? Any advice Kenny?
 
Fuel smell?

That spells gas vapors.

Perhaps you are referring to a hot machinery smell?

Possibly a blowby smell from engines/generators?

I can help you with those, but not the gas smell.

That needs to be handled at the source.

RWS
 
If you smell fuel, find the source IMMEDIATELY -before you have an explosion!!!
 
Ditto all above but if your return air path has access to the bilge it will pull vapors in and pass them to the cabin.. Fix the source of the odors, and duct up the return air path.
The priority should be resolution of the vapors at the source.
 
Are you sure it is gas vapors?
Our boat had a funny smell that we thought was engine room smell, only when the a/c was running.
I sealed off all bulkhead penetrations and places that I thought might leak any smell into the
cabin. Still, every time we ran the a/c, we got a strange smell. I later found a crack in the
head that let some nasty stuff get into the cabin bilge. I cleaned out the bilge area and changed
the head and all blackwater hoses and then cleaned the evaporator coil with coil cleaner and it
got a lot better. We finally figured out that the remaining smell was in the carpet from all the
time that the smell was in the boat. We removed the carpet and installed wood floors and now
the cabin smells good.
After 29 years of absorbing smells, cleaning the cabin bilge and changing the carpet made all the
difference in the world.
Check your cabin bilge area. Take the carpet out and see how that works.
 
I personally think it is just the engine compartment smell, but the better half maintains it smells like gas. I did have a shower drain come off the catch basin in the bilge and after cleaning, it was a lot better. I tried to check all the bulkhead seals, but a lot of them are hard to see. Still there are drain openings to channel water between the bulkheads. I never smell anything in the cabin without the air. Also, I can never distinguish fuel smell in the engine bilge.
 
Same with us. The smell wasn't quite what the engine compartment smelled like.
It only happened after running the a/c for a few hours.
Never when the a/c was not running.
 
Most (if not all) air conditioners are not ignition rated and do not belong in the engine room or anywhere they can be in contact with fumes, such as a bilge open to the engine room.

Unless this was a non-factory install, my guess is that there should not be a path for fumes to get into the air conditioner, unless something is very wrong.

Perhaps its a different smell?
 
We have a self contained unit mounted inside the cabin, there are no parts located within the engine compartment.
I know of a lot of a/c condenser units located in the engine compartments of gas powered boats, straight from the
factory. They are ignition protected as long as the controls are mounted in the cabin.
 
I assumed it was a factory installed unit but as I said, I have come across the same boat with a more isolated installation (under the salon couch). I have also seen photos with different return grill installations. If it was an original installation,I don't understand why the evaporator wasn't directly ducted to the grill. As it is it will draw air from the front bilge area. I just wondered if anyone else had come across this installation and if direct ducting cured it.
 
I believe ABYC standards recommends that AC return air be isolated from the bilge, unfortunately some builders (installers/DYIers) dont' do it.

you can either duct the return between the grille and the AC unit or, if the distance is short, build a box/enclosure using foam sheets and alum. tape. That works well and will let you ensure no bilge air comes in.

as to the engine smell, that's a little odd, air from the ER shoudl not be able to get in the forward bilge although since gas vapors are heaiver than air, they are less likely to migrate forward.
 
Had a similar situation a few years ago with a 34 C Silverton. factory installed AC under dinette bench seat, completely isolated from the bilge. After a cruise one day, came back to the marina and turned the AC on. Shortly, i smelled gas. When I went into the engine room, found fuel leaking from the stbd Holley carb. Imediately shut off the fuel lines and pulled the carb. A rebuild solved the problem, no problem since.
 
I will isolate the grill intake but the other thing that just came to me was that it was only the women who said it smelled like gas but the men all seemed to think it was something different... How odd? Perhaps another topic?
 
There is a Trojan International here in Lake Charles that has the whole a/c system in the
engine compartment. The owners and kids went out for a night and came in too late. The
fresh water barrier was closed for the night. So the owners wife and kids called someone
to come get them at the freshwater barrier boat launch. The owner anchored out for the
night to wait till morning to get thru the barrier.
The next day when he didn't show up, his wife called the barrier to see if the boat was
still there. They said yes, the boat was still anchored there. The owner wouldn't answer
his cell. The barrier employees took a boat out and the owner had the boat locked up and
didn't answer them. The owners wife told them to break into the forward hatch. When they
did, the owner was unresponsive, but breathing. They brought him to the launch and an
ambulance brought him to the hospital.
Long story short, his a/c was in the engine compartment. The blower was on, but the blower
duct was under water in the bilge and not sucking any air out of the engine room. The
generator exhaust was integrated into the stbd. engine exhaust. The stbd. exhaust manifold
had a small leak. The gen. exhaust filled the engine compartment with CO and the a/c sucked
some up and discharged it into the cabin.
The guy survived, but does have a few minor physical problems.
We looked at the boat, but backed out after he told us the problems he had with the boat.
 
My 10 Meter International has the compressor and sea water pump in the engine room.
Everything else is made into the bulkhead and the ducts run through the salon ceiling.
The exhaust is separate from the engines.
Perhaps this AC was an add on?

the better moral of that story is to maintain smoke and CO detectors in every cabin of the boat.

ANY BOAT, gas powered, diesel powered and with or without a genset.

RWS
 
His boat looks exactly like yours. But I don't know if it was an add on.
I saw his old manifold after it was changed out. The generator exhaust
goes into his stbd. manifold.
His exhaust outlets are several holes just after mid ship, on both sides.
I have only seen this type exhaust outlets on 2 Trojans in our area.

We have a small boat, but we have 2 CO detectors and 1 smoke detector
inside the cabin.
 
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