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preservedkillick 09-14-2010 09:44 AM

Suddenly buring oil?
I just noticed that my Vetus has burned through nearly half a quart of oil this season ( ~60 hours ) when it burned none last year and I'm wondering why. Transom is extra sooty.

Possible reasons:

1. Temperature alarm sounded twice on the shakedown this spring due to low coolant level. Engine was shut off immediately, cooled for 15 minutes between. After this I changed the oil as a precaution. I don't have a temperature gauge. Vetus tech support tells me the alarm is at the very low end of the "high temp range" and are researching the actual temperature the alarm goes off at for me. It's not in my manual. Damage done? Head gasket? My oil looks fine, as does the coolant. Engine runs fine.

2. New prop this spring. Campbell Sailer prop. 12" diameter x 8" pitch. The prop appears to be right for the engine. I can reach hull speed at 3000rpm's (max). Too much pitch? The old prop was a large three bladed thing with unknown pitch.

3. Wrong engine oil? Last year I ran 10-40 which is what my manual calls for. This spring I put in 10-30 (NAPA was out of 10-40 in my favorite brand). I would not think that slightly thinner oil would make a difference.

Opinions from those more knowledgeable than I? Anything else? My next visit to the boat I'll change out the oil back to 10-40 and keep an eye on it. Wish I had a temperature gauge.

cardiacpaul 09-14-2010 12:17 PM

Smoking, if so, what color is it. Black mean fuel, blue/gray means engine oil. (water is white smoke)

1/2 a quart? thats not a lot really.
10-30, 10-40, shouldn't be noticeable difference.
3000rpm? thats a lot, isn't it?

Maine Sail 09-14-2010 01:25 PM

What is max rated RPM of the Vetus. You should be able to hit max rated RPM at wide open throttle with a clean bottom and prop. You'll ideally want to be within 100 RPM of max rated. If the engine is rated at 3600 RPM you are simply over pitched. If max rated is 3000 RPM then you are spot on.

preservedkillick 09-14-2010 01:39 PM

Hey Mainsail,

max is 3000 according to my manual. I think I'm ok on the prop. 6.2 knots is hull speed, which I hut at 3000 RPM.

I just got a call back from Vetus and the support guy could not find documentation on the temp that triggers the high temp alarm so he asked a tech there at vetus and was told 212 deg F! That's stinkin hot! Not much of a warning if that is true. I wonder if I damaged something with overheating. Head gasket? I can barely see smoke when running, not sure on color. My transom is extra sooty dark though, at the exhaust port.

Gene T 09-14-2010 01:49 PM

What is WOT for your engine. If WOT (wide open throttle) is 3000 then you need to run it at ~2600-2700. If you are running at WOT they you will burn oil and ruin your engine. You must be able to hit WOT in gear under full power, but you must not run there for more than a few minutes. If you can't then you are over propped.


preservedkillick 09-14-2010 02:25 PM

WOT is 3000 rpm's, max rpm's is 3000. I ran it up to max rpm's once this spring to test the new prop. I typically run at 2200 to 2400.

Gene T 09-14-2010 02:54 PM

Thanks for clearing that up. I agree with Paul that 1/2 quart is not a big deal. Soot on the transom could be a dirty injector.


preservedkillick 09-14-2010 03:22 PM

Yeah, if all I need to worry about is adding half a quart of oil every season I'm not concerned. I'm just looking for a reason. Specifically, did I damage a head gasket or worse with the over heat. I think leaking head gaskets are a bad thing with diesels, from what I've read.

When I think "oil burning" I think piston rings, unless the oil is making it to the coolant. The oil has no obvious signs of water. Black and thick.

When I look back at the exhaust, I barely see a little smoke of some sort, very light almost a fog. Certainly not dark. I thimk I see it more with polarized lenses. Trouble is, I don't know what "normal" is.

I'm not even positive the sooty transom is a new issue. Last year I had bare dry gelcoat. Didn't look great, but was relatively stain free. This year I have a coat of Collinite Fleetwax. Looks great, but with the warm days it softens and stains. I've also got black streaks under the deck skuppers.

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