My first diesel -how much water from exhaust?

[ARadcliffe]

Running an Irwin 10/4 with a YSE8 diesel. Bought it last year and have been working on it all spring bringing it up to snuff.

Being new to a diesel inboard, how much cooling water should I see coming out the exhaust?

I did have it gone thru by a mechanic after a stalling incident during an all-day transport run thru the oswego and erie canals. Although it runs smoother now (new fuel pump, replaced some fuel lines) it definitely isn't flowing as much water as it was before. The engine seems to be running a bit hot - but I don't have a good basis for comparison to know how hot it should be running.

Not sure if the water is vaporizing in the exhaust. Exhaust is light grey to white. It's not dry, but it's not much more than a trickle - I was expecting at least healthy spurts...

Thanks!

 

[Ross]

It rather sounds like a worn impellor. My little 10 horse Volvo will empty a five gallon bucket in 2 or 3 minutes at a fast idle.

 

[ARadcliffe]

Ross- thanks for the calibration on the amount, that is exactly what I was hoping to find out.

It's definitely not doing that kind of flow.

But I think it was before the mechanic looked at it.

Could be weeds in my intake, too - going to check that first, then start to go thru the loop...

 

[higgs]

Replace the impeller. It is not hard or expensive and it eliminates the most obvious source of the problem. If the old impeller is missing vanes, then you need to work down the system to make sure a stuck vane is not impeding flow.

 

[Ted]

My first diesel - how much water from exhaust?

If the impeller checks out okay, try looking at your exhaust elbow. I'm not familiar with your engine but most diesels are similar. Check to make sure that the area near where the cooling water enters the exhaust elbow is not obstructed. The volume of water that Ross mentioned sounds about right. Don't expect a steady, full flow of water coming out of your exhaust.

 

[Ross]

Re: My first diesel - how much water from exhaust?

The water discharge from the exhaust comes in slugs. the muffler fills and the pressure blows a slug of water out and I get a few dribbles and another slug. Perhaps one second apart.

 

[okawbow]

My YSE8 will empty a bucket at between 1-2 gallons per minute. The top of the engine will be very warm to the touch, but not too hot to lay my hand on for a couple of second. It will run all day at that temperature.

 

[Don12364]

Unscientific but gurgle, gurgle, splosh, splosh is about right - and no steam.

 

[Scott T-Bird]

This spring I had a weed clog ...

that I didn't look for until after I changed the impeller. The symptoms were the same as yours, with a diminished flow of water (my wife said it must have an old prostate gland) and greyish smoke. Maybe my experience is different than others but I have never had diminished flow from a failed impeller ... it either flows when the impeller is normal or there is absolutely no flow when the impeller fails. What puzzles me is that I have changed 4 or 5 impellers and there has not been an instance where I can see or feel anything wrong with the failed impeller. No missing vanes, and they feel equally flexible as a new impeller. I simply can't distinquish any difference between an impeller which has failed and a new one. I even saved a bad one once and tried using it the next time I needed a new one (which happened when I had the weed clog and thought I needed the new impeller). Nope, it didn't work even though it seemed no different than a new one.

Sorry for the long story, check your intake hose for weeds first ... I found weeds just in front of the glass filter bowl that is mounted ahead of the water pump on my boat.

 

[FastOlson]

Along the path of trouble shooting exhaust quandaries in a boat from the late 70's / early 80's...
it's not uncommon for the exhaust hose itself to start to fail after decades of heat and use.

What I have seen is a piece of the inner liner loosen up and form a sort of aneurysm. This can change the flow, the sound, or even totally block most of the exhaust and water from getting thru in an extreme case.

Somewhere on your preventative maintenance list on any boat at the third decade should be a new exhaust system.

As to why a new impeller works better, I'm not sure, but have also observed the increased flow when a new one is put in... and the one I took out has all the vanes and "looks fine" to me.

Best,
L

 

[RichH]

All Yanmar engines use an "oberdorfer" type raw water pump system. Each engine has a SPECIFIC requirement/specification for the raw water flow vs. specific rpm.
Call a Yanmar dealer (Mack Boring in NJ , Torreson Marine in MI are major "master' Yanmar distributors) and get correct advice of this value.

Take this value, get a bucket of known volume, get a stopwatch etc., run the engine until warm (T'stat fully open) at the spec. rpm and measure how long it takes to fill, etc. the bucket while collecting the 'output'. Then compare the actual output value with the specified. DONT GUESS if you have any reason to believe that the flow is somehow 'diminished'. Remember that the flow will NOT be continuous as there is sometimes 'lag' of flow in the water lift muffler .... so you will have to measure over a 'long' period of time to get the 'average'.

BTW - most 'standard' oberdorfer-type vanes raw water pumps will deliver approx. 3 gallons per minute at ~2000 rpm.

 

[ARadcliffe]

What everyone was describing is what I had on my ride down to where it stalled. Glug - glug-sploosh and all that, and the heat of the engine was just like owkowbow said.

So I know that what I saw yesterday was definitely not enough water, and was running too hot. It was steady-state at a higher temp and not getting worse, but was too hot.

Thanks everyone - this is really helping.

So I went to Ess-kay yards here in Brewerton and got a new impeller on the way out to the boat. (Thanks Higgs and others - sounded like the plan no matter what the deal or the problem, cheap and easy job for cheap insurance!)

Got there, with the plan to check the flow from the thru-hull back up to the engine.

While I was unscrewing the double clamps attaching the hose to the thru-hull fitting, I looked and realized that the hose from that fitting up to the strainer looked collapsed. I replaced it when I put on a new strainer, and the bend between the thruhull and the strainer must be too much. It was fine for awhile, but must have softened at some point and collapsed, limiting the flow.

So I did the check anyhow, opened the thruhull and watched the water flow nicely out of it and into the bilge. Minimal if any weeds.

Tomorrow's plan is to put a 90 degree elbow in the middle of the intake hose and take the bend out of the hose - but I am questioning the type of hose I am using. Seems like automotive radiator hose should have been fine - it should be under more heat in that application than any cooling water intake should ever be. Perhaps I exceeded the bend radius, and I won't make that mistake again - but is there is a special type of hose I should be using here? You can bet I'll call ess-kay where I got the impeller (as the proprietor knows I am new to diesel and is taking good care of me - took me back and showed me on a diesel generator how to backflush the cooling water system in case there were any impeller parts or debris that got loose) and ask them the question as well!

Then once that's installed I'll run it with the currently installed impeller, check the flow vs. specs per Rich H and see if we're up to specification. (Am an engineer,so I like that I can measure this and know it's all good or needs replaced - in God we trust, all others bring data!)

Any deviation and it's out of there for the new one. If it's perfect then I'll have me a spare. Also have previous owner's email - and he's a good egg - and will ask if it was replaced in his tenure with the boat.

Again, thanks to everyone for the help, it's greatly appreciated.

Perhaps the next question I post will have to do with actually have to do with a time when the engine is off and the wind is blowing...

Best,
Andy R
Irwin 10/4 - slightly overcooked...

 

[Ross]

I used heater hose for my water lines intake. They are rather thick and difficult to pinch shut but all of my bends are large radius.

 

[Cayennita]

Back in 1995, while motoring into Norman Island in the Bahamas, my Yanmar engine overheated and shutdown. I unfurled the genoa and made a safe passage through the reef and dropped the hook. 1st thing I did was look at the impeller. Nothing wrong. The whole system checked ok.
Don't ask how, but the shaft key was gone. I know it was there when the impeller was changed while motoring down the ICW. Happen to have a spare and all was fine after that. Another time the impeller looked good, but the rubber had separated from the shaft. Then another time was the collapsed exhaust hose. Never mind the times with weeds and jelly fish sucked into the line and strainer.

 

[ARadcliffe]

Got it fixed - put a reinforced hose instead of a plain heater hose on it and got gallons of flow.

The hose has a spiral wound wire embedded in the rubber, so even when coiled up twice as tightly as it sits installed the boat it stays wide open.

Once it was installed, tested it by idling the diesel a half hour and it stayed nice and cool. Big, big difference. Am considering myself lucky I didn't end up with a big lump of molten Yanmar.

Will be doing that gallons/rpm test in the next day or so to see if the new impeller needs to go in or is now a ready spare.

Thanks again to everyone who chimed in with information and advice, it is greatly appreciated.

A

 

[Deleted member 78819]

Fresh water cooling system...

My Yanmar has a fresh water cooling system and a heat exchanger between the fresh water system and the system pulling water through the impeller. Even if you are moving enough wather through the impeller you will run hot if your fresh water side is low on coolant. I don't know if you have a fresh water system but, if you do, be sure and check that as well.

 

[shorty]

like this

my 3GMF 21 hp should have a shot like this every 2-3 seconds at idle