Sea flush

[Capt’nKarl]

Greeting fellow TugNuts,
I seem to be having a decrease in water flow from the outside engine exhaust. Although the engine temperature alarm has not sounded I’m concerned about build up in the heat exchanger causing this low flow. The impeller and water pump belt are new and seem to be working fine. The heat exchanger has never been removed or “flushed”. I’ve seen several YouTube videos where the exchanger has been cleaned without removing it from the engine by running Sea Flush through the system and letting it sit for 4 hours. Doesn’t anyone have any experience using this stuff and if so does it work? Any information would be appreciated.
Karl

 

[Newf]

Hi Karl,,I had not flushed my heat exchanger, not being aware of the need to do so and ended up with some very real problems that I'm now trying to deal with. Read my previous post on heat exchanger inspection and look at the pictures in my album. I did not see a flow restriction with mine but found an issue when I pulled off the end cover on the heat exchanger.

How many hours do you have on your engine? I'm not a mechanic but If you are seeing a flow restriction I would not just rely on the flush. I would take the end cap off and make sure there is nothing else going on with your exchanger. PS..if you do this, suggest you have new o-rings on hand. Feel free to PM me if you want to discuss further or email me at marcelis@telus.net.

 

[captstu]

Check your exhaust elbow where the salt water exits the heat exchanger and enters the exhaust flow. These sometimes clog and must be checked every 500 hours or so.

 

[Newf]

Good Point Captstu. I did not have any buildup in my exhaust elbow at 1460hrs (Volvo-Penta D1-30) but everyone's engine and operating conditions would be different so he may have build-up issues as you noted. Have you ever pulled the heat exchanger core on your engine or have a recommended hours where you would do this? I cannot find anything in manuals for this service and didn't get any feedback on this in a previous post. My manual only noted a flush at 500 hours. Tks..

 

[Capt’nKarl]

Thanks for the responses. This is my 5 am wake up from a dream of my boat overheating reply so be kind to me. I have a 2009 boat. The engine is a Yanmar 3YM30 with about 500 hrs. We use the boat in salt water but I store the boat on a trailer and always flush the engine with fresh water after each outing. I’ve never pulled the exhaust elbow to visually inspect it and as I stated the engine is not overheating but there has definitely been a decrease in the amount of water “burping” out of the exhaust port. Yesterday as I was running the engine at 3000 rpm while cool water was flowing into the water intake hose I also observed what appeared to be steam coming from the exhaust. Using a laser temperature device the outside temperature at the exhaust elbow stayed around 150 degrees F. Otherwise the engine runs like a champ. There is some rusting on the external exhaust elbow but no water leakage. The antifreeze solution is 5 years old but looks like new. Maybe I’m just being paranoid but I know there has been a visable change and just have a feeling there is not enough water being discharged. I don’t think the Sea Flush would hurt anything so that’s my plan for today. I’ll let you know if there is any difference in the discharge after using this product. Good morning all.
Cheers,
Karl

 

[Rwnorton]

I have a 2016 Volvo D3 so things may be different. But I learned the following recently the hard way. After a soft, slow grounding in mud my engine temperature was rising rapidly..On the D3 the first thing salt water passes through after the strainer is the transmission cooler which is about the most accessible thing on the engine. We removed the intake and output houses and flushed and the problem was cured. Happiness is knowing that crud gets trapped first in an easy to fix location. And while this may not be your problem, it’s really easy to check.

 

[captstu]

Yanmar small Engine exhaust elbow raw water injection ports are known to clog at 500 hours or so for f run at low rpm. Remove the raw water hose and probe the elbow with a plastic straw.

Inexpensive to clean or replace.


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796

 

[Kaisardog]

the heater exchanger on these yan mars have a multitude of very narrow tubes. if even ONE of the small tubes gets clogged you will see an increase in the operating temperature . (monitoring average operating temps in a daily log is always a good idea...) pulling the heat exchanger to clean these tubes (with a narrow file) is easy and may solve the problem. if the overheat is a 'sudden' thing, it's more likely to be a clogged tube than a clogged exhaust elbow ( I've seen and rx 'd both over the past 35 years on my yan mars. ) the ht ex tubes can become clogged from a small piece of zebra mussel shell or a bit of rubber from the raw water impeller vane. these are then propelled thru the raw water system and get stuck in one of the ht ex tubes. Procedure: Plan to order a set of ht ex gaskets from your yan mar dealer. the gaskets are uniquely shaped and will easily be damaged when you remove the ht ex 2 end caps. (in an emergency you can try re using the gaskets and sealing with 'form-a-gasket' sealant from the auto parts store...) when you remove the end caps, you will have access to the 'core' of the ht exchanger. use a flashlight and see if you can see a blockage in any tube. if so, clean it. when you are replacing the end caps, be sure to tighten the retaining bolts in a pattern of 1 and 3 then 2 and 4, ( not 1 2 3 4 which will cause a torque on the cap that may prevent a good seal and result in a water leak. ) you may also wish to check boat diesel.com which has an index to each engine and various maintenance procedures. my boat diesel.com subscription allows me internet access to the service manuals and parts manuals for my yan 3JH 4 E , and is an invaluable resource. (i also carry the 'paper' manuals ordered from my yan dealer... which have saved me $1000' s in yard maintenance bills and allowed me and my engines to be pretty much self sufficient on the water. ) 🙂

fair winds, calm seas...

 

[Newf]

Have you checked/replaced your pump impeller. Missing or partially missing impeller vanes will reduce the amount of flow. Broken vanes can also make it's way through the system resulting in partial blockages. The Volvo Penta D1-30 calls for impeller inspection at 500 hrs but I've had to replace mine at 400 hrs intervals due to cracked vanes. Yanmars may not have this issue.

 

[Jim and Jackie]

I had two Yanmars on my last boat a 3GM30 and a 3YM30. Thirty years ago I took a diesel course, the mechanic who taught the course recommended replacing the raw water impeller every year and replacing the mixing elbow every five years. His rational was, for the impeller it was cheap insurance and for the elbow they were clog roughly every five years. Whether it was good or bad advice I never had a problem with a failed impeller or clogged mixing elbow.

Last year, when I bought our 2010 R 29, I had them pull and clean the heat exchanger, replace the impeller and the engine belt. They said the heat exchange did need to be cleaned even though there were less that 500 hours on the engine. They recommended that the impeller be replace every 2 years.

A lesson learned. Last year I had asked the yard to replace the impeller and filters on the generator (it only had 80 hrs). They kept putting it off and we ended up taking off on vacation and having it cut short when the impeller self destructed. I didn’t do it myself cause I just ain’t as young and flexible as I used to be.

Jim Demerest
2010 29 Chessie