1999 or 98 Yanmar 36 HP, Model no. 3JH2E has bluish white exhaust

Apr 30, 2016
48
Hunter 376 Port of Los Angeles
My Yanmar 1999 or 98 Diesel, model no. 3JH2E, 36 HP, 3 cylinder has bluish white exhaust. The hour meter reads 373 hours. (so it saids for a 20 year old Yanmar). Engine does look clean. No leaks and no major residue.

The engines starts up with no problems. And runs good. All though I’m a newbie with diesels and boats. I bought my 1999 Hunter 376 sailboat two years ago.

1) Understand maybe diesel fuel less than 45 cetane can be a source of bluish white exhaust.
2) I did accidental top my oil level above the full dip stick line about a 1/2 inch. Maybe that’s a source.
3) I added maybe more than 2 OZ. of Starbrite “Star Tron” Enzyme diesel treatment to my 30 gallon tank. Maybe that’s a source. ( I only filled the tank twice about 10 gallons each time in 2 years since owning the boat).

I don’t remember seeing bluish white exhaust before I did items 1,2,3 above. I only been out on the water 5 times in 2 years since owning the boat.

Now I believe it’s bluish white exhaust. I will check it again to make sure it’s not just white exhaust.

Is there any other reason why white or bluish white exhaust is caused?

Thanks all,
FriscoRon
 
Feb 20, 2011
7,990
Island Packet 35 Tucson, AZ/San Carlos, MX
2) I did accidental top my oil level above the full dip stick line about a 1/2 inch. Maybe that’s a source.
Most definitely a source. If anything, slightly less than full on the dipstick is preferable to too much.
 
Apr 30, 2016
48
Hunter 376 Port of Los Angeles
I changed my oil and oil filter. And oil level is just below high mark line on the stick.. However I'm still getting what I believe is white smoke from exhaust when I ref the rpm up to 1500.

Also I noticed I'm getting a slight oil sheen on the water near the exhaust. I will have to determine if it's diesel or oil.

Appears I may have another problem. Or Maybe it's part of the same problem. My raw water hose outlet keeps popping off my heat exchanger. This is also happened when I was out in the water 2 weeks ago. I replaced with new Stainless Steel hose clamps. But it keeps popping off.

I'm wondering if the exhaust mixing elbow is clogged. I heard you have to clean them. Even though I'm a newbie. It appears the raw water exhaust is spitting out the back of the boat on higher rpm's.

Can this be back pressure from a clogged mixing elbow causing hose to pop off the heat exchanger outlet. And how do I test for clogged mixing elbow? Appears the elbow is threaded on a rusty 1 1/2"- 2" nipple before it connects to the flex exhaust pipe. LOL.

Attached is pictures of my heat exchanger hose, mixing elbow, and my 1998 371 hour Yanmar 3JH2E engine.

I will also post video of white exhaust and oil sheen behind the boat tomorrow when the sun is out.
Attached Thumbnails
 

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Feb 23, 2018
52
Hunter 356 Marseille
For less than $250 change your exhaust elbow. I do this with every sail boat I've bought. The exhaust bluish white can often be water vapour... your elbow and heat exchanger needs a bit of looking after. My mecanic takes the heat exchangeur and cleans it with electrons in a special liquid bath. A new joint and a few hours of labour... it's well worth it especially if you don't use the boat that often :)
 
Apr 30, 2016
48
Hunter 376 Port of Los Angeles
Thanks Secret sail,
Maybe a new elbow would better along with cleaning the heat exchanger. What's the "new joint" your talking about?
 
Jan 12, 2016
268
Hunter 410 Ladysmith, BC
One other thing to look at is your operating temperature. On our boat we have the same issue. Fuel injectors pulled and cleaned didn't solve it. However our thermostat was stuck open and the engine would never fully warm up causing the issue.
 
Apr 30, 2016
48
Hunter 376 Port of Los Angeles
Hmmm.... I will check out the thermostat. I do have idiot lights for Temperature. The only time the idiot and alarm went off was when heat exchanger outlet hose keeps popping off. Which I believe is do to back pressure from clogged exhaust mixer elbow. I will find out as I begin removing elbow. Where is that Thermostat on a Yanmar 3JH2E anyways. I guess I will trace that down too.
 
May 8, 2017
43
Hunter Legend 35.5 Lake Balaton
Hi,
I have the same Yanmar and reading your reply I noticed I had the same problem: the engine run at low temperature and does not warm up. So the thermostat stuck open, too much water cools the glycol and engine can not warm up. Question: does anybody know how to get it unstuck?
 
Apr 30, 2016
48
Hunter 376 Port of Los Angeles
I have taken off my mixer elbow, exhaust manifold. Looks like elbow is definitely clogged. Looks like I'm getting my parts from https://hdimarine.net/ out of Washington state. A fellow sailboat owner member told me about this site. Thanks Charles. :)
 
May 8, 2017
43
Hunter Legend 35.5 Lake Balaton
Hi,
The thermostat on mine is where the cooling water enters the engine block. It sits right there.