111

seguir

111

kneedeep

I think that's about 24 ounces, 3 per hour, if I'm doing my math right. Both of my engines burn, I tracked it last year but haven't this year. One burns less than 2/ hour, the other burns more than 2/ hour. My merc mechanic contacted merc & was told that up to 3 ounces/hour is fine. I've read many posts on this subject & lots of people say they've had their engines for years & don't burn a drop. Many others, like me, do burn. I am concerned, but also under warranty for 2 more years. I do check the oil several times per weekend if I'm doing a lot of boating.

212rowboat

you should never burn oil... 

start simple, first... check your pcv valve... 

a pcv can hang and use the vent like a drinking straw... it should rattle when you shake it.. 

if it's not that, and there is no leak, the options narrow drastically, and get more expensive with each of the two remaining options... 

kneedeep

Uh oh. What are the 2 remaining options? I shouldn't trust merc who says up to 3 ounces/hour is fine?

Black_Diamond

3 oz per hour?  That's a lot!  I'll knock on wood as I say this, but in a normal season of about 40 hrs of use, and even trips of 3-4 hrs at a crack I burn nothing.

212rowboat

oil doesnt cross paths with air/fuel, and should never burn... 

valve seals... not a hard job, and not too pricey.. maybe $200 in parts and three hours effort.. you dont have to pull the engine.. quite a bit more effort than a $5 pcv valve, though.. 

the other is spent piston rings, slapping it in the cumbustion chamber, and burning it... now we're talking big bucks... 

if the pcv sticks, it is amazing how much it can suck up... that much in that little a period would lead me that direction, and i ain't trying to blow sunshine in your drawers, either. :-) 

212rowboat

if it isnt the pcv, do a compression test and cut to the chase... there is no sense replacing valve guides if the heads are coming off, anyway..

the pcv may or may not rattle.. if it is the culprit, evidenced by dripping oil, it could either be it OR rings still.. blown rings make crankcase pressures higher quick like and can push oil the same way..

kneedeep

when I got my boat at the beginning of last season, I looked up what wot should be & verified that I was reaching it. I'm not 100% sure, can't remember now, but I believe it is 5200rpm's for 09 Seacore 350's in a 340. I only run up to wot a few times a season & only for 30 seconds or so. I probably cruise 30-40% of the time slow & the rest at 3800-400rpm's. I change the oil twice a season & use merc 25 40. I'm away this weekend, but when I get home I'm going to check the Pcv. Thanks guys.

kneedeep

I usually store my boats at a yard that is close to my house but is not a merc dealer. I'm going to travel this fall to a merc certified yard that I trust & I'll have them do compression test, etc.

seguir

I will check the PVC Valve today....where can I find it?

seguir

Thanks....Going to check it now.

212rowboat

here is the thing about PCV's, too, that lots of folks look past:

they are so dang easy to manufacture, every low quality manufacturer on the planet spits them out- and they are inferior products that need replacement sooner than later... in that vane, it is mucho better to purchase a quality product instead of el cheapo...

go to a dealer to purchase this thing.. just about any dealer who sells/maintains v8's will work.. you'll likely not get the stiff arm if you go to a chevy dealer, as a Chevy Small Block (CSB) pcv is a CSB pcv no matter the application...

Michael T

Seguir, if you are burning 3 oz of oil per hour I think you have a problem. Knock on wood the only engine I have ever had that burned that amount of oil was the older version 502s and they were just oil burners right from the factory. I have never heard of 350s (and I've had a ton of them) burn 3oz mof oil in the time yours has - unless something else was in play. Easiest for YOU to do is to check your rpm range you can do that no cost. As Al said you should be right at the top of your WOT range. Second easiest and therefore cheapest thing for YOU to do is check your pcv valve, as said, it should at least make a clicking noise or small rattle. Easy/cheap to self test and replace. Third easiest/cheapest thing YOU can do is to remove, carefully, your spark plugs. A while back I posted a note on what to look for regarding colour and "damage" and drewactual posted some great pictures. If all of the above prove okay you can have a compresion test/leak down test done. That should be able to be done by a certified tech in 30 to 60 minutes tops. All of the above said, Al really hit a homer with his lugging comment.  How high an rpm do you run when you are displacement cruising (not on plane)? You can burn unusual amounts of oil if  you are running your rpms too high at displacement. I'm sure you have seen obvious examples of boaters lugging (flogging) their boats at displacement - bow way up, stern way down, rpms way up and a rooster tail/wave behind the boat. Those guys should just shoot their engine to put it out of its misery. I'm sure you don't do that but that's an obvious example of hard use of an engine(s) that will burn oil. Your on plane rpms seem okay -  3600  should be fine for your boat 3800 is okay with a bigger load of guests or gear. Remember - you have a single engine, which is more sensitive to loads and your EC 280  is a big boat for a 5.7 to push. I assume your 280 is a few years old. How old is the engine? You say that it only has about 65 hours on it and you put 40 of those on it? Why so few hours on the engine in a 280? Is the engine a rebuild? Did it sit for awhile at the dealers or someone's house? Let us know how things go. MT

212rowboat

yup... the spark plug won't lie, and you will see pretty quick what's been going on in that chamber by 'reading' it...



pay particular interest to oil fouled plugs... they will be gummy, and show a lot of oil has been burning- usually, though, these happen on the count of blown valve guides/seals.. again, that isn't a hard thing to replace, and requires only a couple tools you may or may not already have.... personally, I prefer a coupler and air compressor to do these..

high RPM's create higher pressures in the crankcase (duh).. :-) ... that will have its way with a weakish PCV, and cause siphoning to happen... 'floating' the valves at high RPM happens, in rare cases (rare on engines with rev limiters), which takes the burden off the valve spring, and in turn allows 'wiggle-walk' to take place on the valve guides/seals, which allows oil past..

the leak down test mentioned by Mr.T above, along with reading the plugs, will tell you about all you'll need to know.. the test consist of a dry compression test, and then oil introduced to the cylinder to see if the compression alters drastically (gets more compression).. you don't want that.. you don't want more than a 10% difference dry:wet... and then the leak down itself- which is basically watching the compression escape, which will show you if the valve seats are shot..

seguir

PCV valve looks ok...nice and clear and shakes.

212rowboat

you burned so much oil, so fast, that there is something going on in there beyond any doubt..

as Al and Mr. T said- high rpm's generate higher crankcase pressures- there is no way around that.. the RPM's would allow more oil to slip past a valve guide/seal than normal, and the added pressures could push oils up and into the intake...

pull your air-hat off and look for evidence of oil inside the intake itself.. it will be evidenced by a sheen, and readily identifiable as oil.. what this will tell you: it's your PCV, whether from a bad PCV or from excess blow-by (bad rings) will not be determined, but if it's NOT there, you may be able to lean more towards valve guides/seals..

212rowboat

here is what yours truly would do, if it were me in this situation:

I'd route the PCV drift into a catch can instead of in the path of the intake.. into a nice clean catch can.. I'd top off the oil, and go for a run of at least moderately high RPM's for at least fifteen or twenty minutes.. I'd then check the oil level and the contents of that catch can..

having vaporized oil in small quantity is no big deal..

having standing oil says that the pressure is exceeding the PCV's ability to flutter, so blame the PCV

having a considerable amount of oil splattered about as if it were sprayed in there under pressure, well... that can only be excessive blow-by pressures caused by weak rings.. ruh-roh, raggy...

having none, or very little: we're back to valve guides/seals..

seguir

Michael, We bought his boat last fall with 27 hours on it, it was used for one season and sat for a couple of years. When we first got it, it was overfilled with oil.  I removed about 2 to 3 liters from it. and did a number of runs with it.  There has been no oil burns till this weekend when we ran it for 9 hours, 4 hours then 5 hours to come home.  I check the oil before we left for home and it was down about 1/2 litre and when I check it again when we got home it was down a little bit less, but had to top it up again..  

When I am not on plane I am not that **** it, never above about 2800 RPM's.   On this trip I ran it at 3600 to 3800 RPM's with 5 people on board and the boat packed.   The lake had no waves both ways.  We used 420 liters of gas during the 9 hours run time. 

aero3113

What weight oil are you using?

seguir

25-40

Michael T

Seguir, The way you used the boat should not have, in my opinion, resulted in the amount of oil consumption you describe. Your rpms (3600-3800) should not be a problem at all. It may be a more simple explanation. Look at the pcv valve. Also, depending on your engine some valve stem seals dry-out/harden/become brittle and loose their ability to seal if they have not been run for extended periods of time - and - two years IS an extended period of time. IF this is the case it can result in higher oil burning numbers.Good Luck! let us know how it works out! MT

212rowboat

Michael T said:

Seguir, The way you used the boat should not have, in my opinion, resulted in the amount of oil consumption you describe. Your rpms (3600-3800) should not be a problem at all. It may be a more simple explanation. Look at the pcv valve. Also, depending on your engine some valve stem seals dry-out/harden/become brittle and loose their ability to seal if they have not been run for extended periods of time - and - two years IS an extended period of time. IF this is the case it can result in higher oil burning numbers.Good Luck! let us know how it works out! MT

+1

I'd tell you the first order of business is to pull the plugs and read them.. it will tell you a lot in a short period- for instance, if there is oil fouling across all eight, then it is almost certainly oil being inducted into the intake... if it is just one (or two) plugs, it is almost certainly blown valve guides/seals on that (those) particular cylinders.

edited to add:

a hundred times, at least, I shaken a pcv valve to determine if it was good or not, and it rattled- so I went looking elsewhere.. it is true that they hang up and won't rattle when they are bad, but that doesn't mean they aren't weak and not being held in suspension when the engine revs enough to create pressures... get a QUALITY one, my friend.. they are worth the extra couple bucks.... the drift/pipe/hose running to the intake manifold should be dang near dry.. if it has oil inside it, of amount enough to wet a q-tip, it is in the wrong...

seguir

I spoke to the dealer who sold me the boat.....He is telling me that during the first 100 hours it is normal to burn the amount of oil I did.   Is he telling me a line?

 

Drewactual....I was looking to see if I can pull the plugs...They are not easy to get to are they.  I will give it a shot to see if I can do that myself. 

212rowboat

he's not feeding you a line... new engines need to 'seat' the rings, wear in the bearings, and other such things that happen in a rotating assembly- this is why a lot of builders use break in grease/oil- when tolerances are tight, the parts in question don't 'float' on oil so much as 'flow' oil... flowing oil, sometimes makes it past rings and burns.. parts and pieces will 'marry' over time and use, and start to perform as intended, though, in short order.. its been my experience it doesn't take 100 hours, though... more like 40 or so... of course, the hotter the engine (195~205* auto; 160~175* marine) and the type of metals used in the bearings (aluminum or brass) will dictate how quickly and efficiently that happens... the metals used in engines have a (insert fancy metallurgical name here) coating that are used for a very specific and narrow temperature range- like maybe 30* range.. failure to use them in that range will cause excessive wear (and that is above OR below the intended range).. this is why bearings and valve seals fail, along with them drying out due to non-use..

yes.. plugs like to hide under risers and manifolds in these things, and require certain contortion skills to get at... :-(

edited to add, just for the heck of it:

the first oil change is uber important for this reason, if not alone: there are not only tiny shards of metal in that oil change, but also the remnants of this coating on hard parts I spoke of above... that stuff, if allowed to remain in an engine too long, will cause excessive wear wherever it is circulated... soft surfaces, such as valve guides/seals are especially exposed.. 

MarkB

I went through this exact issue last year on my 260 EC fitted with a MAG 350 5.7L. Brand new boat and engine. Ok engine had 5h on it from dealer tests.

Up to 30h of service there was no oil burn. Then oil burn started happening an getting worse.

I would go on a 2 hour boat ride and have to add 1/4 quart of oil. Longer trips was a full quart per leg. It was getting ridiculous. I couldn't see evidence of oil burn, no smoke, nothing.

I was told oil burn was normal, especially in he break in period. But something about traveling 100 km and needing to add a quart of oil didn't seem right to me!

This site (old Rinker Forum, same folk) encouraged me to investigate further. So I did.

We pulled plugs, all clean. We did a compression test and.... cylinder 3 didn't hold!!!

It near the end of last season so we hauled the boat to the dealer for more tests. They visually saw an oil sheen in the cooling water return. They confirmed cylinder 3 wasn't holding pressure.

Once we had that information Mercruiser was quick to to help. They agreed to replace the engine under warranty and were quick to make that happen.

This year is a totally different story. My fuel consumption is better, and no oil consumption. After my 20h service I put fully synthetic oil in the pan which I'm glad I did.

One thing I noticed is you burned a lot of gas for 200 km trip. At that rpm you should get about 0.75 to 0.8 km per litre. So you should have used around 300L of gas.

Everything you describe is close to what happened to me. I would do a compression test it is the only thing that found my problem last year. Mercruiser will want that done anyhow before they will make any move on warranty claim.

Michael T

Seguir, I'm with drewactual on the ring seating. The dealer and even Merc will probably say 100 hours+/- to seat. Maybe 40 but I'm thinking 20 to 25. IF the engine has been broken in properly the rings, in my opinion, should have achieved their "set" forever at about 25 hours ***Remember Merc itself says to do your first oil change at 20 hours - so they must expect the rings to have seated by that time!. Just to be sure I called an old friend who has been building engines since the 70's everything imagineable (auto and marine). He said "  We run every engine we build on the computerized dyno for 10 hours, then we retorque the deck and check all tolerances. We then run it for two more hours and give the owner our print-outs. If your rings (compression and oil control) haven't seated by 25 hours they never will or the engine was not broken in correctly. If an engine is burning oil out of spec at 100 hours it was either mishandled, there are either damaged parts or it needs a rebuild". My opinion to you is that I would NOT worry until you have performed a few of the (already mentioned) cheap and easy tests.* Thinking out loud I'm wondering if the engine was run with way too much oil by the previous owner. If so, that MAY have blown the valve stem seals. At high rpms way too much oil (like you told us about) can cause hydraulic lifters to collapse putting pressure on the whole valve train assembly and causing seals to blow. Try the cheap tests first. Fingers crossed for you! MT

 

212rowboat

+1 on markbellino above...


just because I'm bored, this may or may not be of use for future searches:

reasons oil escapes:

- you've got a leak....

- your pcv is sucking into your intake due to a failing valve stuck open... it generally happens at or just off of idle, where vacuum signal remains high (14+ inches of vac), and the valve doesn't seat closed... evidenced by a not rattling PCV when shaken, but not always.. may be evidenced by dripping oil from the hose connected to the intake when it's removed.. may be evidenced by oil present in intake manifold, as seen through the throttle body into the plenum area, or on blades of a carb..

replace the PCV valve with a quality one preferably from a dealer, not a discount parts store.

$10 and five minutes.

- you've a leaking valve guide/seal... generally happens with excessively dirty oil allowing deposits to settle on them, or worse: be squeezed between the mating surfaces and score the seal.. it can also happen to them as a result of 'drying out'.. it can be determined by pulling the plugs from each cylinder and seeing if there is any oil fouling on the plugs... if so, that cylinder is the one with valve guide/seal issues.

replace the valve guides.. pull the valve covers, pull the spark plug, use a compressor and coupler to hold the valve in place, pull the rockers, retainers, and springs, fish the guide out and slip a new one in its place, reverse the process.

eh... $100~150 in parts and pieces if you drain and replace oil, replace vc gaskets, replace plugs and maybe plug wires. takes likely three to four hours.

- your piston rings are worn, allowing blow-by from the compression process to positively charge the crankcase pushing oil not only past rings during the exhaust stroke, but through the ventilation ports into the intake... there is no quick fix for this.. a compression test will determine if it exists, both dry, then wet- there should be little difference between those two readings.. a leak down can be performed at the same time, to see if compression holds or seeps out due to a bad valve seat...

it's pull the engine time if this is the case... $xxxx.00 and days downtime.. pistons gotta come out of there, honing or boring has to happen, new rings or new pistons+rings introduced, ect.. it is such a process that I can't imagine why it would be done w/o a complete rebuild at the same time.

(note about compression tests: make certain your valve event timing is right- if you attempt to do a compression test with even 1 degree of valve opening (intake or exhaust), it won't compress, or it will leak down quickly.. make certain the engine is at top dead center on the compression stroke)..

Gentlemen, I hope your issues are simple.. valve guides aren't a big deal, and PCV's are dead simple... there is nothing comfortable about a rebuild, though.

seguir

Markbellino as well makes a interesting statement in my fuel consumption.   I used 420 litres of fuel for a 200 K run. (which he thinks I should have used 300 liters).    At 3600 RPM's My GPS told me I was traveling at  24 kilometers or 15 miles per hour.   I did however have 5 people on board with lots of coolers etc. The Lake was in perfect condition.  

I am waiting on my warranty papers and will have a compression test done.

MarkB

At that RPM, you should have been doing over 20 mph. Are you sure you were on plane?

That feul consumption is high for a MAG 350. At around 30 mph, I get 2 mpg consumption, or 0.85 km/L. At 22 mph, when I plane it is around 1.8 mpg or 0.75 km/L.  Over 30 mph it quickly goes to 1 mpg consumption.

Keep monitoring your oil level. Start a record and include date, average RPMs, peak RPM, run time, distance, water conditions, fuel level change (or % used), oil level (inches or cm on dipstick from top or bottom), oil added (mL), new dipstick level. This will provide data to prove or disprove theories, plus provide a trend to see if things get worse. Mine did.

Michael T

Seguir, you say you have a 5.7 that's 300 hp so I have been assuming that you have a 350 magnum, is that correct? As well, Mark asks a very important question - were you on plane at 15 miles per hour? I don't see how that boat with that load could possibly hold plane at 15 mph or 24kph. I don't see how you could be turning 3600 rpm and be at 15 mph?! My 2011 Rinker 226XL with a 350 magnum and B lll drive could barely hold plane at that speed with just me in it. If your boat was not on plane then the oil burn and gas consumption start to make sense. Something is "out of whack", in my opinion, when all of the stats are considered. MT

seguir

Now I am wondering if I was on plane.   When I start off I have the trim tabs down I bring the boat to 4400 RPM's then I bring it back down to 3600 RPM's.   I am feeling kind of stupid right now.  Could I have caused a hole crap of problems for myself?   At 3600 RPM's I was getting between 24 -25 kph.  How high of RPM's is ok to run on plane, Is it ok to run at 4000 RPM for a extended period of time?  Maybe I have to limit the number of guests I have along and/or luggage on board??

Yes it is a 350 magnum with a broval 3.   The prop is from the factory that came with the boat.