Brand New Yanmar smoking and acting sluggish

[eostheseacat]

Just bought a boat, has a brand new (33 hours) yanmar 75 hp engine. It has been running great for two days although blowing some white smoke.
Today, it seems to be loosing power. Temps is perfect, oil pressure is perfect, but the rpm's are topping at 18. We have been running at 20 for about 7 hours straight. White smoke smells like diesel. Engine is peeing. No ticking sound, return water is not overly hot. Just does not seem to have any get up and go? What should I check or be looking for.

[Fishman_Tx]

"Engine is peeing."?

Sometimes called "wet stacking" when unburnt fuel in the talpipe/stack and lots of white smoke. But...

**First** Check the fuel for water contamination. Fuel water separator and filters. There is a water-finding paste you can get that you apply to a stick and dip the tank. If it changes colors, there is water in it. How high the color change goes up the stick is how deep the water is in the tank. IF it is contaminated, the tank will have to be pumped out and disposed of or run through a fuel polisher to remove the water. A yard may have the polisher, but don't bet on it. Then change out every fuel filter on the engine, re-prime and bleed the system if necessary...and off you go.

Other than that, it may be fuel control; too much diesel to the injectors. Make a call to a Yanmar certified shop and tell them what you got. If they are forthcoming with the info, then you can take it to the local repair knowing the possibilities or do the work yourself. Also, possibly a loose wire in the system or bad sensor.

Personally? I'm betting on water in the fuel!

JMHO

Fish

[sailorchic34]

At 33 hours, the engine is not broken in yet. Per yanmar, new engines should be operated at about 70% of max rpm from 10 hours to 50 hours. There is a guide in the engine owner manual on break in rpms. Generally you have to vary the rpm a bit every so often for the rings to set. You do not run at a constant rpm for 7 hours though.

If it's not ring/ cylinder scuffing, you might have picked up a bit of line on the prop.

[Fishman_Tx]

Wouldn't line in the wheel cause a noticeable vibration? Our Bristol wheel was fouled and shook pretty hard...

Just wonderin'...

[sailon46]

When my 4jh3 HTE did the white smoke it was vacuum created in the tank and fixed it with taking a kink out of the vent hose. When it did the same thing again two years later it was the secondary (on the engine) filter blocked.
Good luck
Ernie on the Mary jane

[Capt_Bruce]

Disclaimer: I normally don't add my two cents cause I don't know much, but I want to help if I can. :-)
Does it get progressively sluggish as you throttle up? The last time I had what seems to be a similar problem, it was a compression issue. The compression levers had been accidentally moved (they were located on top of the engine near oil cap). Albeit, it was a smaller Yanmar on a Hunter 280. I just moved them to the forward position and problem solved. I hope it is something that easy for you.

[zstine]

Both 2000 and 1800 are relatively low rpm for cruising, though I don't know the specifics of your engine and you didn't say where your throttle was at those rpm. But you make it sound like the max(?) rpm your engine will reach now is 1800. I'm guessing you got a new prop with the engine and perhaps the prop is over pitched preventing the engine from reaching optimum rev range. I think being over prop'd could cause smoke (darker color though) as the engine lugs with the high load, low rpm condition. Just a thought. What rpm will the engine get to with no-load, in neutral? Does the engine smoke at 1800rpm with no load or is that only when in gear? What is the specified max no-load and cruising rpm for this engine? You said it seems to be lacking power. Are you approaching hull speed at 2000 rpm? you say no noise.. no vibration either? "white smoke" could it be steam? Some engines seem to always have steam in the exhaust, while my water stays in liquid form as it exhausts. I'm not sure if steam is indicative of a problem or just the way some engines run.

[krafthaus]

A guy I know had a similar problem on his vessel. It turned out when the manufacturers drilled the holes for fittings in the fuel tank (plastic) they didn't clean out the little plastic bits and this almost completely plugged the fuel line. The pieces didn't even make it to the filters.

Same as you low revs & white smoke.

Good luck to you. 👍


Sent from my iPhone using Cruisers Sailing Forum

[jhulmer]

Sounds like a fuel supply problem to me. Put a vacuum gage between the Primary filter and the engine filter, if it reads more than 3 or 4 inches of mercury then you have a clogged filter or fuel hose.

Is the engine Turbocharged if so, check that the turbo is turning. they stick sometimes if not run often and cause a low power situation.

Also, check that your not using coolant, which could be bad, ie: blown head gasket. I doubt this based on your description.

hope this helps,

[Cheechako]

All good suggestions above. One note, was it good at first? Where are you located? Was the boat store for a long time while re-engining? In Florida the little bees clogged up my tank vents by building mud houses in them (in 3 months of storage) Based what little info we have my thoughts are:
-wrong prop
-fuel restriction

[boeing1]

sounds like fuel problem, a friend have same problem after re engine there boat. ran OK for a day of two that had power problems. what hp was that was in the boat before repowering

[anacapaisland42]

I had problems with a new gutless Jetta diesel.
On the advice of the local (best) diesel shop I ran a couple of tanks of STANADYNE thru it.
Cleared everything up on tank 2, better MPG, more guts,etc.
Bill

[01kiwijohn]

White smoke = unburned fuel. Check for injector not atomizing (Fuel injector shop job), way too cold engine temperature, stuck open compression release (it will be accompanied by miss-fire), or poor quality (perhaps incorrect) fuel. At those low hours it should be a warrantable issue, so check with a Yanmar dealer after verifying those external factors.

[dietervoegeli]

White smoke = lean mixture. Lack of Diesel. Filter clogged or burning of crankcase oil by increasing the oil level by using the engine at low speed for too long.
Aligning the piston rings also cause burning of the crankcase oil.
Black smoke = too rich mixture.

[Polar Opposite]

I'll offer something else to check: The engine/shaft alignment. Since you just swapped in a brandy-new engine, the alignment was disturbed and may not be right, causing the shaft to side-load the power train. You want this checked an re-checked to prevent very rapid wear of your cutlass bearing.