Diesel smell in aft cabin

Andrew Dickson · May 31, 2013, 01:16:15 PM

I have a 2000 MKII. After running the engine for any length of time, there is a strong diesel smell in the aft-cabin. Are there any tricks to get it out of the boat quickly so the smell doesn't linger...or better yet...not have the smell linger at all and go out the exhaust?? The captain really doesn't like the diesel smell when she is in the galley so she closes the door.

Jim Hardesty · May 31, 2013, 02:20:53 PM

Is the smell diesel fuel? Or, is it a hot engine, hot oil smell? I'm quessing it's not diesel fuel. It may be the engine oil breather tube. It was on my 2001. There is a post here to add a filter to the line and plumb the breather tube to the air intake. It cured my engine smell. Till you get that installed, try running the engine vent fan.
A differnt fix. Get a longer breather tube (auto parts store) and run it into a beer can filled with airconditioner filter foam.
Try the google search (from the C34IA home page)
Jim

Ken Juul · May 31, 2013, 02:55:47 PM

If you think it is a fuel smell, check the lines and fittings under the head sink. Very easy for the smells to migrate from there to the aft cabin. May also want to pull the port wall of the aft cabin and make sure the tank, fill or vent lines aren't leaking.

If it is just the engine smell, running the blower when the engine is on and for a period after shutdown may help. Jim probably guessed right with the breather tube, very easy to reroute to the intake filter area. Then you just have to remember to clean the foam every so often. There are a couple fixes where you tap into the manifold and run the vent tube directly there, you can also put a fitting on the intake filter assembly and run the vent tube to it.

Mike and Joanne Stimmler · May 31, 2013, 03:14:56 PM

Is this a new or existing smell?
In addition to the above suggestions, you may want to check the exhaust hose that runs from under the bathroom sink to the aft of the boat.

Mike

Ron Hill · May 31, 2013, 03:17:51 PM

Cut a fuel diaper to fit - place it under the engine and check to see it you have a fuel leak!

Andrew Dickson · May 31, 2013, 03:31:27 PM

It is the hot engine smell...no leaks...but definitely a diesel finish. Thank you for the quick responses. I'll do some digging about your suggestions, Jim.

Stu Jackson · May 31, 2013, 07:28:30 PM

In addition to the earlier good advice, you should carefully check the connection between your exhaust riser and the flange on the engine.

Roc · June 03, 2013, 04:22:38 AM

If you've gone through all the checks to make sure nothing is leaking, it's probably the plastic fuel tank. I have the same situation. Pull the wood cover on the port side to expose the fuel tank. The odor permates right through the walls. Take a sniff and you'll see.

Indian Falls · June 04, 2013, 05:49:40 PM

Since you indicate that you only smell this when running, it says to me it's exhaust gasses or crankcase fumes.

Running your crankcase breather to filter media will remove oil vapor but not the smell of burned diesel blowback from the cylinders. I ran my breather hose to the air cleaner with 1/4" parker pushlok to a fitting I epoxied into the top of my air cleaner cover. No filter seems necessary to me.

The other thing is leaking exhaust manifold or cracked muffler fitting, loose hose clamp, or anywhere exhaust gas can leak out of
the exhaust system. I ran the engine with my muffler drain petcock open.. it sure does smell the place up.

2ndwish · August 21, 2013, 07:34:09 AM

Indian- Do you have a photo of the intake mod? Did you just drill a hole in the round filter cover?

Ron Hill · August 21, 2013, 01:23:10 PM

Andrew : How is tracking how the diesel leak coming?

It has been my experience that if it smells like diesel it is diesel. If the diesel smell persists it is a persistent leak because the diesel smell goes away over time from a one time leak/spill.
(unless the spill is into something like the foam of the sound proofing)

my thoughts

KINGAIR350 · August 21, 2013, 05:13:06 PM

Have you over filled your tank ? If it had vented out port vent on the stern , i would take a look there and take off/out the port wood and check out the line and the gasket to the fuel sender .
Good Luck !

Indian Falls · August 21, 2013, 06:13:49 PM

Hey 2nd Wish,

No pic required. I drilled a hole in the cover of the air strainer. I did use the proper drill size for the 3/8 npt fitting and I did thread the hole with an npt tap, even though only 1 thread gets cut in the cover. I then epoxied the fitting into the cover and connected my 1/4'' air line between the valve cover and the air strainer.
This is my opinion: it is a waste of money and time to add any filtering device to this line. As it has already been found by another member... a clogged element in this line caused a great deal of trouble. There is really no reason to put any thing in the line. Nobody on this site has ever said they found "significant" amounts of oil leaving the engine through this hose... I'd rather have the engine suck in all that stinky crankcase fume instead of smell it down below when motoring. You can put the end of this hose in all kinds of media to remove particulates and micro-droplets of oil... but nothing will change the smell of crankcase fumes. I don't miss it, and I've had it hooked up this way for 150 hours of run time. I have 1500 hours on my engine hour meter... so she's still young.