Slight exhaust smell

[simdim]

Folks,
Now since we had re-raked the mast our e29 sails sweet ( thanks to everyone on this forum for the help), but Admiral had noticed that there is exhaust smell in the cabin and port lazareth.
PO had retrofitted Yanmar 2gm20 and from what I can see all ventilation hoses are a mess - there are holes and kinks int exhaust vent hose and kinks in the intake. Also exhaust blower is not firmly attached to the engine compartment. Should I start from installing new vent hoses and inline blower like this one http://www.defender.com/product.jsp?path=-1|6880|46775|732133&id=714108&cartId=1027884 and hard wire it to the ignition or should I start looking for the exhaust leaks?
With exhaust leaks - unlike the car where it is all easily accessible - how one goes about looking for leaks on a boat exhaust system?

Cheers,

 

[Guy Stevens]

Fix the leaks.

There are generally a few places that it can leak. The easiest place to start is to look for water leaking.... If there is no water leaking then it is before the injection nipple on the exhaust, if there is water leaking then look for where it is leaking.

QED.

Oh and by the way, an exhaust leak can kill you all very fast, faster than you would guess. Also CO exposure is cumulative so this weekends adds to next weekends.... Depending on your metabolism it can take up to 3 weeks to eliminate the co buildup in your system.

Guy

 

[simdim]

Guy,
Let me get it straight - irrelevant of the condition of vent hoses there should be zero exhaust smell aboard. Since there are no water leaks that I can see - I should start at manifold and follow it to the riser.

Cheers,

 

[Maine Sail]

It's likely

Crankcase ventilation. Most engines have a hose running from the valve cover to the air intake to re-circulate these odors from inside the crankcase..


P.S. Diesel exhaust produces considerably less CO than a gas engines exhaust and death from diesel CO poising are rare, very, very rare.

Diesel exhaust has a neat "built in" feature for safety in that it produces sulphur dioxide that can cause nausea. You will get very sick to your stomach long before the CO has affected you. This nausea is not life threatening and can in fact be life saving.

 

[u079721]

Second the crankcase ventilation

I second the suggestion about crankcase ventilation. The Universal on our E38 really filled the cabin with an exhaust-like odor when underway that really used to get to my wife. But that odor completely went away when I ran a hose from the crankcase vent to the air intake.

I have read that this might not be a good idea, becasue of the slight negative pressure that case be formed on the crankcase with this set up. But the result was so positive that I would never change it back

 

[simdim]

Folks, I looked over yanmar manual - the closest thing i can find that what matches the description is a "breather"?

Cheers,

 

[Guy Stevens]

My nose is more sensitive I guess

I don't think that the crankcase and the exhaust smell the same, but that could be what Simdim is smelling. I have a picky nose..... But if you look around the engine and don't see any leaks, don't feel any leaks, and have no water leaking, then it may be that you are smelling crankcase fumes.

If it is Crankcase venting, then the easy and correct way is indeed to get the crankcase fumes back into the intake and burn them through the engine.

Incomplete combustion of a fuel source causes CO, diesels are not immune. The ultra low sulfur that we are all forced to burn now produces less sulfur dioxide and a lot less smell. Bio diesel smells like french frys..... While it is rare to have a Diesel kill someone with CO, it is not unheard of.

Be careful with this.

The breather could be the crankcase vent.

Guy

 

[u079721]

That's it

Folks, I looked over yanmar manual - the closest thing i can find that what matches the description is a "breather"?

Cheers,

That's what they call the vent. On my 5432 (M40) model it was a right angle fitting on the port side of the engine with a rubber hose of about 12" or so attached leading down towards the oil pan under the engine. I drilled a hole in the side of the intake housing and installed a right angle fitting with a hose nipple, and ran a new length of hose from the "breather" vent to the air intake nipple fitting. My engine suffered from a bit of "blow by" oil coming out of the breather vent, and this oil then began leaking out of the bottom of the engine intake, but all it took was an occasional wipe down with a rag to clean the drips off.

 

[Martin King]

I'm going through this right now. I've got a Yanmar 3gm that while
it ran fine, seemed to put just enough fumes in the cabin to make
me sick whenever I went below. I replaced the entire exhaust from
the manifold up to an including the undersized through hull. Still had
fumes though. Next, I pulled the head off, had new valve guides
installed, shaved off a couple thousandths and reinstalled with
new gasket. Still had the fumes. After having 3 different diesel
mechanics look at it, I reluctantly concluded it was blow by, and
needed new rings. Nothing left to do except bite the bullet, and
do the rings. It's currently in pieces while the crankcase went
to a machine shop for boring. Yanmar makes oversized rings
for just such an occasion.

Martin

 

[simdim]

Fumes were not exhaust after all ....

Close examination of the problem yield the following results: there was a leak in the fuel return line and it was dripping diesel on the engine - hence nauseating fumes. So this is fixed ... however while snooping with inspection mirror I had discovered that there is reddish liquid dripping on the bottom of engine / transmission joint. It feels more like antifreeze then trans fluid. I am a bit at loss where that can come from unless the PO had not winterized properly and now I have much bigger problem to deal with...

Cheers,

 

[treilley]

If your AF is green then this is not it. Tranny fluid is red. That location indicates a bad input seal on your tranny. Check the level before you run the boat again.

 

[simdim]

Treilley,
Just looked into service manual - your explanation makes perfect sense! It also may be possible to take trans out without lifting out the engine.
This is our last weekend in the water - haul out Sunday ...
Do I need to get a special trans fluid or my normal "automotive" grade will do for the last cruse?

Cheers,

 

[treilley]

Most trannys use automotive type atf but check your manual to confirm. Sometimes it will say on the top of the unit too.

 

[simdim]

It is antifreeze ...

Further inspection of service and operation manuals for Yanmar 2GM20F revealed that trans uses the same oil as crankcase (mobile 20W-40) and the jug of antifreeze from PO revealed that it is indeed reddish in color. So I am back to the starting point in the hunt for a leak...

 

[Emerald]

I believe the heat exchanger on your 2GM20F is like the one on my 3GM30F. On the aft top of the heat exchanger is a little elbow that a hose attaches on to take the discharged sea water from the exchanger to the mixing elbow in the exhaust. I've had issues with the O-ring on this little elbow leaking and being the source of a mystery leak down the backside of the engine. It's a 40 cent part that can drive you nuts....

 

[simdim]

Ok guys, where would I be without this forum

Emerald,
Is am I looking at the right O-ring (see attached image)?

 

[Emerald]

The O-ring I am thinking of is #6 under the elbow which is #5. The one you have pointed at seals the end cap on the cooling/exchange tubes inside the exchanger body. It is worth also checking if it isn't #6. Note that the elbow actually pivots, and there is a set screw that holds it into the body - #7 looks like the set screw.

 

[simdim]

Problem resolved

Folks,
After I had service look at the engine and tell me that it is coolant that is escaping from the cap and there is too much coolant pressure that might indicate piston problem (read - we have no idea what is wrong but will spend a lot of time and charge a lot of money) I decided to take another look.
Ran diesel for 30 min waited for smell and reddish liquid in the bilge to built up and finally determined that it is diesel fuel... Followed all the supply and returned lines now with a mirror and sure enough - fuel pump is leaking from the gasket. I will try to re tighten the cover but from the experience diaphragm pumps do not respond to that procedure, so time to pull out another 1 boat unit of currency ($100) and get a new pump.

Cheers,

Simon

 

[Loren Beach]

Pump note

Simon, be sure that you have read the prior threads here on electric fuel pumps, if that's the leak you refer to. (Before you spend money on a new one.)
If it's the Universal/Westerbeke 12 volt pump (actually an un-labeled Facit pump) there is a gasket and filter inside the bottom screw-off cover.

Best,
Loren

 

[Martin King]

Loren,
I think he's referring to the cam driven lift pump on the engine.

Martin