Optimax excessive oil consumption. Plug pics included

[Mr. Demeanor]

I am only getting about 35:1 with my 2003 225 Opti (OT701465) running Premium Plus. I pulled some plugs and this is what they looked like. The prop was just labbed by Leading Edge and after 4 hours the hub is already black and sticky. The plugs were oil as eveident on the threads. They have about 50 hours on them and I run Merc Quick Clean religiously.
Searching for info I came across someone with a similar issue that was resolved by replacing the cylinder block check valve (#7 and part number 21 - 43278 1 on the "Cylinder Block and End Cap" schematic).
Does anyone have any experience with this checkvalve and could it cause this issue?

[Mr. Demeanor]

Doing a little digging on that part number I came up with this service bulletin stating the check valve has been redesigned.

http://www.marinepartsman.com/Mercur...1991/EN_15.PDF

[Pro300x24LD]

Hmmmmm my 300x appears to run oily by your standards....my prop is rather black as well....

[Mr. Demeanor]

I pulled my old checkvalve today and it seemed plugged up. Sticky would be a better description. I cleaned it with carb cleaner and will clean the hub and one plug. I will be out on he boat all weekend so hopefully I will see a difference.

[Mr. Demeanor]

Nothin? Well, I should know tomorrow if cleaning that sticky check valve did any good.

[Scream And Fly]

Has the engine been scanned with a DDT?

[Mr. Demeanor]

Has the engine been scanned with a DDT?

Yes and everything was good. No codes and sensors within factory limits (TPS etc.).
I ran 55 miles today and it appears to be burning less oil but I need to pull a plug and refill the tank to get a percentage.

I dont understand how this check valve would cause over oiling. If anything, I would think it would cause oil starvation as it supplies pressure to the resevoir.

[sosmerc]

Is this the checkvalve on the side of the block where the pressure hose to the boat mounted oil tank is hooked up?
If so, the check valve bleeds off pressure to the tank when you shut the engine off. If it gets plugged the boat mounted tank remains pressurized and will force oil to the engine while the engine is shut off...this might explain the oily plugs and perceived high oil usage.
to test: shut the engine off and wait about 5 minutes. Then, open up the cap on the boat mounted oil tank...if you hear the hiss of escaping pressure you have a plugged crankcase check valve.
How many hours are on your engine? Are you past the break-in period? (the engine will double oil for the first 120 minutes above 2500 rpm if the engine ECM sees the correct load conditions)
I reset the break-in during winterizing so that next season the engine will get extra oil...so my customers may or may not be aware of it, but they should be using a bit more oil than normal for awhile...but it's a good security blanket after a long winter season of storage.

[David L]

My 225 X smokes way too much after a 10 minute or so warm re-start. My X has this similar valve, I'll look at this evening.

[Mr. Demeanor]

SOSMerc, that is the valve. I pulled a plug today and it looked better. I only ran about 50 miles so I am going to run a full oil tank through and get an idea of useage and take another peak at the plugs.
Today I stopped by a marina that services mercs and looked at the prop hubs on a bunch of optis. They all looked horrible. Mine actually looks better than most of the others I saw.

[Pro300x24LD]

Mr. Demeanor, how much oil are you using?

I have a 70 gallon tank on the boat, and a 5 gallon oil tank. Seems I add about 2-3 gallons every time I fill the boat up, I usually put about 50-55 gallons in the boat.

Does that seem high or good?

[sosmerc]

Your consumption does indeed seem pretty high. If you ran exactly 55 gallons of gas at WOT you should use just a little over 1 gallon of oil...this is a 50:1 ratio. However, you may want to consult with a Merc Tech at High Performance because they may have the performance optimax engines programmed to use a bit more oil than the standard production motors. I wonder if there is any chance the engine ecm is stuck in break-in mode? (I have never heard of this happening).

[Pro300x24LD]

Your consumption does indeed seem pretty high. If you ran exactly 55 gallons of gas at WOT you should use just a little over 1 gallon of oil...this is a 50:1 ratio. However, you may want to consult with a Merc Tech at High Performance because they may have the performance optimax engines programmed to use a bit more oil than the standard production motors. I wonder if there is any chance the engine ecm is stuck in break-in mode? (I have never heard of this happening).

Well I do pretty much run at wide open the whole time I'm out.....

This was a very UN-Scientific measurement. Motor does not smoke at all....I will keep an eye on it from here on out and see if it seems abnormal.

[sosmerc]

One thing about Optimax motors: on some boat/engine combinations the engine is using less fuel (gph) at a fairly high throttle position but at the same time the oil pump is supplying oil for an "expected higher rate of flow...so in the end it makes it appear you are using way too much oil. This has been a fairly common observation with Optimax owners.

[Pro300x24LD]

I am not an optimax though being a 300x correct?

I guess I just jumped in here because my prop is usually pretty black as Mr. Demeanor observed and wondered if it was something to be concerned about.