engine burns oil now.

Old Fart · **Joined:** Fri Jul 23, 2010 12:08 pm **Posts:** 28

Hi all

I have a 2007 H190 with a merc 4.3 mpi with 170 hours on it, I bought it in 2010 with 50 hours on it. My first summer I did about 55 hours on mineral oil and never added any all summer and I check all fluids before we go boating, its a ritual for me. Last November when I got it winterized I asked the shop to replaced the oil with 100% Merc Synthetic. This summer I have added close to 2 liters of Synthetic oil to it and not sure why. I don't smell oil fumes in the exhaust, I don't see oil stains in the boat hull but I realise its going somewhere. Its probably burning it I just can't tell. Now what is the problem? Should I not use Synthetic oil?

Walt · **Posted:** Sun Oct 02, 2011 11:57 am

I find I have to add about 1 qt of oil after a few runs following an oil change. Not consuming oil by any means, just filling the filter, etc. I also make sure I have the boat parked in the same place, same angle, etc since that could cause variation.

Places to check... oil line on the stern; burn oil in the prop hub; anything in the bilge (try a wash out); breather line/air cleaner; vacuum hoses.

230 Mike · **Posted:** Sun Oct 02, 2011 12:42 pm

Do you smell it if you run on muffs? It does seem like it must be burning it, but on a 170 hour engine, that sure isn't right. Of course a car dealer would tell you its perfectly normal. In any case, the synthetic should not be the problem, but you could switch back and see what it does.

wkearney99 · **Posted:** Thu Oct 06, 2011 8:40 am

Another thing to consider is having the oil tested. That'll tell you if there's excessive wear or blow-by, among other things.

ric · **Posted:** Thu Oct 06, 2011 1:59 pm

Do you run the crap out of the boat? Full throttle everywhere?

Old Fart · **Joined:** Fri Jul 23, 2010 12:08 pm **Posts:** 28

No I don't run the crap out of it... lol 90% of the time I run at 3000 rpm, 30 mph or 4000 rpm, 40 mph, its very rare I go to red line it does happen but only short 5 to 10 minute bursts.

I have checked everything you said Walt and I can't see any evidence. I will get it winterized next week and I will ask them to test the oil and to check into this problem, I will post back with details.

Thank you all for your replies

wkearney99 · **Posted:** Mon Oct 10, 2011 7:56 am

5 to 10 MINUTES? ABOVE the red line? You do realize that's BAD for the engine, right? The point of the red line indicator is to tell you where NOT to run the engine beyond.

LouC · **Posted:** Mon Oct 10, 2011 11:32 am

You could try switching back to the conventional oil, and do some diagnostics. For one, when you do a cold start, have someone standing at the rear of the boat to see if you get a puff of smoke when starting the engine from cold (valve seals or guides). You can do a compression test but before that look at the spark plugs, see if they look oil fouled. If so you have found the cause, now you have to find the specific reason (leaky valve seals are not uncommon on Chevy small block engines). But I'd try going back to the conventional oil first and keep an eye on it, if you can get an oil analysis on the oil in it now.

And BTW, I never have run the engine at the redline, only at the max rpm listed for the engine, and only then for a second to make sure it reaches the specified rpm, to make sure the prop is right for the boat.
My engine is the same but 24 years old, I will run it up to 4000 rpm once in a while, but most of the time I am cruising at 75% of the redline (5000 rpm) which works out to about 3500-3800 rpms, that is what gives you long engine life. These are not high rpm engines like Yamaha 4 strokes, or 2 stroke outboards that don't have a valve train.

Paul I. · **Posted:** Mon Oct 10, 2011 1:38 pm

I agree with both Bill & Lou!! You should never go above the red line, after all, thats way its there. Myself, I almost never go beyond 4000RPMs. I mainly stay around 3000 to 3500RPM, why push it so hard.

What is the wight of the synthetic oil that you are using?? I use Amsoil or Mobil 1 for years, with no problem at all.

Walt · **Posted:** Mon Oct 10, 2011 1:59 pm

Don't sweat too much about running hard.... I'll run WOT/5200 RPM for about 10-15 min to "blow out the gunk". I've even tested the rev limiter once or twice (yup, 5400, it works!)! That means driving fast, making the woman happy, me happy, my passengers scared, and showing off for anyone watching along the river bank. I run Mobile 1 Synthetic (10W-30), change once per season late in the summer and still looks like liquid gold when I do after about 40 hrs per season. I also did the same on my last boat which was a 1992 Merc 4.3LX. No problems there either.

Just get to the root cause on the oil consumption. I'm not saying running hard is good or bad, just that it may not be a contributing factor. I'd start with LouC's suggestion.... compression check and spark plug inspection. Another thing you can do is pull the breather line and check it for oil/residue. That could suggest valve seals.

Good luck!

Old Fart · **Joined:** Fri Jul 23, 2010 12:08 pm **Posts:** 28

Well i can't go beyond red line but damn close, its stops just above 4700rpm and its red line is 4800 rpm and thats with a 1/4 tank, no wind and mirror water. It never beeps so I guess the rev limiter doesn't engage, Its the right prop for the boat I guess.

I thought they were built stronger then auto engines because they need to run constantly at high revs compared to cars that just shift gears to bring down the rpm's. I realise running it at WOT for extremly long periods of time can't be good but they should be able to take it for 5 to 10 minutes every 15 to 20 hours of just crusing at 3000-3500 rpm.

wkearney99 · **Posted:** Tue Oct 11, 2011 4:27 pm

It's reckless, at best, to think this 'clears out' anything.

It's one thing to run the revs up on an engine for a very brief interval (like less than 10 seconds). But if you maintain excessively high RPMs you put an extreme amount of stress on the various rotating parts of the engines. All that mass flinging around puts a lot of load on connecting rods, piston rings, bearing, etc. That and you run great risk of a causing a valvetrain-related misfire, potentially leading to nastiness like a piston slapping a valve and things going very, VERY wrong. As in, a blown engine and serious pain in the wallet.

To say nothing of any risks that develop because you've gotten yourself stranded with a dead engine.

So why bother? If you need more speed then buy the right engine to produce it. Overtaxing an undersized engine is just stupid. But then people make bad choices all the time. Just don't expect to get support for it.

There's really no polite way to put it, running an engine at or past redline for any duration is a just plain bad plan.

Technologic80 · **Posted:** Sun Nov 27, 2011 10:34 am

Are you entirely sure its burning the oil?

Id be more pressed to take a look at the engine oil cooler. Mebets that you have a pin leak and under WOT or high performance runs, its going out the exhaust....

You know and I know the smell of burnt engine oil. If you were indeed burning that much, you'd be smelling it due to the station wagon effect.

ric · **Posted:** Sun Nov 27, 2011 1:09 pm

These are antique design chevy engines. They are NOT designed to cruise above 4000rpms for any duration at a time. If your cruise (3-3500) is not fast enough, get a different prop.

If you insist driving everywhere at 4500rpms, be prepared to buy a new engine. When you do get a new engine, have one built by a performance shop with forged crank, forged rods, ARP rod bolts, forged pistons, dual valve springs, gear driven cam gears (not chain) and titanium retainers at a minimum. It will help survive that kind of abuse much longer then the crap that comes stock.

298VISTA2000 · **Posted:** Sun Nov 27, 2011 4:18 pm

Does anyone know if the 298 Vistas have a red-line? I don't think I have ever noticed one and don't see one in the picture below. I will slam the hammers down to get on plane and then will also run her for 5 or 10 minutes at full throttle every now and then to clean her out. However, most of the time I am cruising around 1800 - 2000 RPMs.

www.iFourWinns.com

engine burns oil now.

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