Question about CAT motor

[raythompson]

It isn't quite a "clear the room" odor, but it DEFINITELY smells like a fart, and not exhaust, which is what through us for a loop.

Maybe you have it backwards. Your farts smell like engine exhaust and you are the one that needs a "tune up" or a break from Taco Bell burritos.

[Duncan]

I want to know if any others with CAT motor owners have smelt this. I feel funny going to the dealer, and telling them my boat farts. ;-)

First, the funny thing, you almost never smell "exhaust" as you smelled before with other boats. It is EXCEPTIONALLY clean. If I rode all day at the back of the boat, I could get a bit nauseous from the CO. That is NOT an issue, and NO FAE. But there is this occasional fart. It isn't quite a "clear the room" odor, but it DEFINITELY smells like a fart, and not exhaust, which is what through us for a loop.

So either my boat has an issue, or other PCM CATs do this, I just have no idea. I may post on WW, see if others have seen this.

We have an '09 PCM 409 CAT with 210 hours. While I noticed a little burn in smell the first few 10 hours or so last season (not a sulfur smell), I have not noticed any smell associated with the boat or exhaust since.

Good luck figuring it out!

[ragboy]

@ray, it just could be.

@duncan, I thought it would burn off, but at like 70 hours now, except I did that quickly. I will give it a few more runs, see if it continues.

[22veguy]

Rag,

Do you think you might be getting a slosh of water up to the CAT everytime you slow down? And then getting some stinky steam coming out? Might be unique to you due to how low you are in the water.
Not sure how the whole CAT system works, or if there is water already mixed in with the exhaust, but it was just a thought.

[Duncan]

Rag,

Do you think you might be getting a slosh of water up to the CAT everytime you slow down? And then getting some stinky steam coming out? Might be unique to you due to how low you are in the water.
Not sure how the whole CAT system works, or if there is water already mixed in with the exhaust, but it was just a thought.

We pretty routinely bury our rub rail in the water and up to the vent ... and I have never noticed any smell associated with that config (PCM 409 CAT).

[ragboy]

We were out friday, didn't smell at all. I just realized, it happens when we surf regular, not goofy. Now let that bounce around the old noodle. The last time was when we had whitney's friend over, she was regular, and we smelled it, and then I posted up here. And the time with Bre, we had James and Chase on, and I smelled it. So, I think if I remember right, when goofy, the exhaust is under water. When regular, its ABOVE water. I guess I will have to weight regular again and test. I wish I had a FART-O-METER.

[zad0030]

Too funny! Indmar CAT does not do this.

Mine does.

Its a trait of the CAT....

[thtrog]

Mine does.

Its a trait of the CAT....

200+ hours and no such smell. Maybe ragboy is on to something...I do have down-turned exhaust tips.

[ragboy]

Mine does.

Its a trait of the CAT....

So Zad, you have that smell also? I also don't notice when riding normal, it must be that by design, that exhaust is under the water level, so it isn't an issue, but when wakesurfing regular, its out of the water.

[lohe]

usually sulfur smell coming from a cat is due to the fact it is working and from to rich of a fuel mixture.

[zad0030]

200+ hours and no such smell. Maybe ragboy is on to something...I do have down-turned exhaust tips.

That could help while underway.

So Zad, you have that smell also? I also don't notice when riding normal, it must be that by design, that exhaust is under the water level, so it isn't an issue, but when wakesurfing regular, its out of the water.

The only time I notice it if I'm on the platform while the engine is running or as I swim up to the platform. Never notice in the boat unless we just came off plane and the wind is blowing the right way?

[ragboy]

Yeah, like I said, I didn't notice at all this last outing.

[IDBoating]

So Zad, you have that smell also? I also don't notice when riding normal, it must be that by design, that exhaust is under the water level, so it isn't an issue, but when wakesurfing regular, its out of the water.

This is very remotely related, but: The Mercury engine in my previous boat was very specific in its installation manual that the mufflers could not be lower than a certain level compared to the waterline. They did not explain why, but I wonder if some exhaust systems are sensitive to the amount of water against which they must "push" or the exposure of some elements of the exhaust system to liquid (as opposed to vaporous) water.

I sure hope not, because my brand new 24Ve has that same EX-343 CAT engine....

[ragboy]

Well, other than that VERY occasional smell, it has been perfect. I wouldn't worry about it. And I will hit 100 hours on it soon, starting around the beginning of August.