posted 04-08-2010 05:21 PM ET (US)            

I think you should start changing your oil more frequently - like twice a season.

I think you might want to talk to the Evinrude guys about a DFI 2-stroke that doesn't make oil, or the Mercury guys about an OptiMax DFI 2-stroke that doesn't make oil.

:)

posted 04-08-2010 06:32 PM ET (US)            

continuouswave.com/ubb/Forum3/HTML/016508.html

continuouswave.com/ubb/Forum4/HTML/004150.html

continuouswave.com/ubb/Forum8/HTML/001207.html

continuouswave.com/ubb/Forum4/HTML/005569.html

continuouswave.com/ubb/Forum4/HTML/001503.html

continuouswave.com/ubb/Forum4/HTML/005028.html

posted 04-08-2010 10:25 PM ET (US)            

--change the thermostats to a higher temperature to force the engine to run at a higher operating temperature at idle speeds;

--change the oil more often than the minimum recommended interval;

posted 04-08-2010 10:29 PM ET (US)            

I once had this problem on a Yamaha F150 that I followed break in on to the letter per the owners manual. I later found out that I should have broken it in to almost opposite to what the manual says. Anyway, the fix for it it was to run 12 gallons of fuel mixed with a shock treatment of Yamaha ring free decarbonizer, and I'll quote the dealer who told me to do this, to "run it like you hate it".

So I burned 12 gallons of new fuel mixed with the ring free at high rpm's, under load, stop to full throttle..over and over..repeatedly. It fixed the problem and it never "made" an ounce of oil after that in the 120 or so more hours I owned the engine.

posted 04-09-2010 02:36 AM ET (US)            

I have a Yamaha Marine Technical Guide for 2004, these provide information to techs of recent Technical Bulletins.
"If customers complain about their F115 "making oil," be sure to ask them how they run their engine. If they typically run are very low rpm for extended periods or in cold waters. chances are they experience an accelerated fuel dilution."
Their fix for 2002 and prior,
ECU
Oil level stick
Thermostat
Spark plugs
Their fix for 2003,
Oil level stick
Thermostat
Spark plugs
Thermostat and spark plugs were hotter ones from the F90. Oil level stick was from 2004 which reduced oil capacity to 4.5 qt from 4.8 qt.

posted 04-09-2010 11:50 PM ET (US)            

Number 9 clearly states the symptom and recommended service.

If the problem has returned with the services performed, what is the WOT RPM reading on your boat?

Do you operate the boat at low rpms for long periods of time?

posted 04-10-2010 02:04 AM ET (US)            

Another thing that can cause the "making oil" syndrome is overpropping of the engine, according to Yamaha.

posted 04-11-2010 02:11 PM ET (US)            

Many outboard start, run to a spot, troll at low speeds and generally don't get alot of continuous upper rpm run time.

Also consider our outboards run in enviroments of colder coolant, lake or ocean water that circulates to the head vs a hot radiator in a car.

Even hotter plugs or thermostates may not help if head temps are not up long enough to burn off these contaminants in the oil

Just a thought

posted 04-11-2010 11:14 PM ET (US)            

quote:

---

One potential cause not mentioned here, though it is mentioned in at least one of the other discussions that Tom referenced, is the fuel pump diaphragm. A split diaphragm will leak fuel into the crankcase, and seems to me the most likely cause if you're seeing a large increase in oil level.

---

This was the problem a couple years ago with my 2004 Mercury 90-HP FourStroke. Replaced the fuel pump and I haven't noticed a problem with the oil level since.

posted 04-12-2010 04:08 PM ET (US)            

In my daughter's '91 Volvo 240 I was surprised to see just how dramatic the water contamination can be. The engine has over 150K on it, runs perfectly and during the year I drove the car 22 miles each way to work it didn't lose or gain any measurable oil between its 5K interval oil changes. The oil remained amazing clean too. This is not unusual for Volvo's 2.3 liter engine. Obviously the engine was "broken in" properly and very healthy.

posted 04-16-2010 09:59 PM ET (US)            

When engine speed is increased above about 2,500-RPM, in most engines there is a mechanism in the cooling system which very rapidly increases the flow of cooling water, and it is typical that the operating temperature of the engine will actually decrease at higher engine speeds as compared to idle or low speed operation.

posted 05-01-2010 12:26 AM ET (US)            

Most cars use a closed cooling system with an air-cooled radiator. The cooling capacity of the radiator is significantly affected by the vehicle speed, with the cooling increasing with increased vehicle speed. This is a great arrangement, because typically the need for more cooling increases with vehicle speed. The more air that blows on the radiator, the more cooling it provides. In this way the cooling system is dynamic. Its ability to cool the engine increases just as the engine power load increases, producing more heat. If the radiator is properly sized, the engine temperature can be nicely controlled by the action of a thermostatic valve that controls the amount of cooling water diverted to the radiator.

posted 05-01-2010 07:26 AM ET (US)            

I doubt the oil in a 4-stroke outboard's oil pan will ever get to 210 F.

posted 05-04-2010 11:55 PM ET (US)            

He stated the "making oil syndrome" is caused by toooo much idle and low load boating allowing uncombusted fuel to leak into the crankcase. We had this problem when I was in the Army, with duece and halves idling for days at a time just to keep the driver warm.

He advices boaters to forget the trimming and make the engine work/develop heat for a period of time. Getting the oil "hot" causes the gas to "burn" off. Makes since to me. Too many 3 year old boats with less than 100 hours. Operator just too concerned with "babying" their baby.