Mercury outboard oil consumption question

[Neptune1]

I have a 90HP Mercury 2 stroke with oil injection which I bought new in Jan 07. I understand that the oil consumption should be between 50:1 and 100:1 depending on throttle and load. I have recently tested mine and am surprised to find over 3 tanks of gas (25 litres each) the oil consumption was approx 42:1 and 37:1. Most of my running is at roughly 70% full throttle which I rarely exceed. Can anyone please explain this or let me know if this is in fact excessive. The motor seems to run well however can be hard to start from cold and is a little smokey when restarted after say a 30 minute break.

 

[Don S]

Re: Mercury outboard oil consumption question

Have you checked to see if the linkage for the oil pump is adjusted properly? Is the engine EFI? What's the Merc serial number?

 

[Texasmark]

Re: Mercury outboard oil consumption question

I have an '02 90 2 cycle carbureted, and the manual for it says 80-1 at idle and 50-1 at WOT. Have no idea how they move from one to the other. Probably a gradual progression.

Mark

 

[j_martin]

Re: Mercury outboard oil consumption question

There's a linkage on the oil pump driven by the throttle. There is a calibration/setup procedure and adjustment for that linkage.

 

[hkeiner]

Re: Mercury outboard oil consumption question

The link and sync procedures for you motor will describe how to adjust the oil pump linkage properly. The attached pic from a Mercury shop manual is an example of this. Your pump may or may not be the same as shown in the pic, but it at least gives you an idea of what you should look for in your shop manual.

 

[Neptune1]

Re: Mercury outboard oil consumption question

The serial number is 1B239984 and I don't think it is EFI. One dealer I spoke to here in New Zealand seemed to think that this oil pump is not adjustable. Does that sound right? Thanks for your help!

 

[j_martin]

Re: Mercury outboard oil consumption question

The serial number is 1B239984 and I don't think it is EFI. One dealer I spoke to here in New Zealand seemed to think that this oil pump is not adjustable. Does that sound right? Thanks for your help!

Mercury parts express is down, so I can't tell from your serial number exactly what the model is.

You should have gotten some paper work with it. It should have a model number that, combined with the serial number, can lead to the exact motor in the parts world.

There may or may not be a mechanical adjustment. It could be controlled by an engine management computer. In that case, there is usually a run in period when it runs extra oil, and also rich in mixture. If you never put the hammer down, that period could be infinity.

Given some more information, I may be able to help.

John

 

[j_martin]

Re: Mercury outboard oil consumption question

I went looking. It looks like a 2007 Mercury 2 cycle engine would be an Optimax DFI (Direct Fuel Injection) engine. Here's a clip from the FAQ page at Mercury Marine.

Break-in is important to insure correct engine performance and life. Follow the procedure listed in the Operation, Maintenance and Warranty Manual. Generally, for the first two hours we recommend avoiding extended periods of idle or wide-open throttle, or holding the engine at one speed for extended periods of time. New two-stroke engines require additional oil during break-in; OptiMax engines use programming inside the computer to increase the oil mixture during the specified break-in period.

Disregard all the mechanical linkage advice I and others have proffered. We all belong to a past era of honkin' carb motas because we can still outsmart the beasts on occasion.

Hope it helps
John

 

[Neptune1]

Re: Mercury outboard oil consumption question

Thanks for your help John.

I found the model number 90 ELPTO and it is not an Optimax. Do you know if this model has the manual adjustment? Is the oil consumption I have recorded excessive or should I not worry about it?

Regards
Andrew

 

[j_martin]

Re: Mercury outboard oil consumption question

Looked up the 90 HP 3 cyl, carb model on mercruiserparts.com. The oil pump is different than the V6, and doesn't seem to have the VRO linkage the V6 does. VRO linkage is a rod between the throttle linkage and the oil pump that is adjustable.

There may, however, be an adjustment. You'd have to look in the factory service manual for this engine.

If it's not a carb engine, I can't find a parts list for it. ELPTO means "<E>lectric start, <L>ong shaft, <P>ower <T>rim, <O>il injected. Fuel delivery is not addressed.

The mercruiserparts parts system is much more limited than mercurypartsexpress was. I hope they come back with a site at least as usable as it was. Mercury sequentially assigns serial numbers. The next number could be anything from a rowboat motor to a V6. The Mercury parts system has a cross reference built in to get directly to the parts list from the serial number.

That doesn't seem to be an 07 engine, more like 90's. It's an early serial number.

On oil consumption, It sounds a little high. Should be pretty close to 50:1 as you run it.

Hope it helps
John

 

[Mercace]

Re: Mercury outboard oil consumption question

If the motor is that new call Mercury and have them send you a new engine. I hear they do that alot due to the high number of factory defects they have. I know several people who received new outboards for similiar reasons.

 

[Texasmark]

Re: Mercury outboard oil consumption question

I have a 90 VRO 2 cycle naturally aspired. J and I have discussed this before. The VRO rate is 80:1 for idle and 50:1 for WOT with some mechanical variance between the two extremes as you move the throttle from one extreme to the other.

Usually engines require additional oil during the first 10 hrs of breakin or so. Double the oil (25:1) is usually the case and you can do that by adding 1 pt oil to 6 gallons of gas which, when added to your normal VRO would give you your breakin mix. When you finish your 10 hrs, if you have fuel left, don't worry about it or fill up with plain gas to dilute the remaining oil

In breaking in, not a lot of idle, and not a lot of WOT. Just a lot of variances between both extremities. Best to get out of the harbor, punch out to get on plane fast, cut back the throttle to just remain on plane...water making a nice Vee 3 -5 feet behind the boat....do that for 10 or so minutes, then a burst to WOT for a minute or two, then back off to half way between just on plane and WOT. Do that for 10 minutes, then cut to idle. Do that for 5 minutes and punch back onto plane and repeat the above. Simple as that.

Mark

 

[HSLucas]

Re: Mercury outboard oil consumption question

The link and sync procedures for you motor will describe how to adjust the oil pump linkage properly. The attached pic from a Mercury shop manual is an example of this. Your pump may or may not be the same as shown in the pic, but it at least gives you an idea of what you should look for in your shop manual.

I'm a dummy, please forgive me. I have an 85HP Mercury, do you have to put oil in somewhere, like a car engine, if so where? I thought that oil/gas was enough?

 

[HSLucas]

Re: Mercury outboard oil consumption question

Need to know correct gap for 850 Thunderbolt, Specs sheet says it is set, I purchased NGK plugs BR8HS, any help?

 

[sschefer]

Re: Mercury outboard oil consumption question

Thanks for your help John.

I found the model number 90 ELPTO and it is not an Optimax. Do you know if this model has the manual adjustment? Is the oil consumption I have recorded excessive or should I not worry about it?

Regards
Andrew

The oil consumption is probably about right on average. There are two marks on the oil pump. The second mark is rumoured to be the breakin mark... It's not. Make sure when the thottle is closed that the pointer on the pump lines up with the first mark. Most manuals show this in the link and sync procedure.

If that's not it, you may want to have a look at your fuel delivery system. If your fuel volume is down the pump doesn't know how to compensate for that and will deliver the same amount of oil no matter what. Permformance will be down but if it's been that way since you got it, you might not know the difference.

 

[Chris1956]

Re: Mercury outboard oil consumption question

HS, Merc 850s normally use gapless plugs, BUHW or BUHW-2. You might advise on the year or serial number so we can verify. Gapped plugs for those motors are not specified.

 

[j_martin]

Re: Mercury outboard oil consumption question

Need to know correct gap for 850 Thunderbolt, Specs sheet says it is set, I purchased NGK plugs BR8HS, any help?

Hey Newbee,
When you want to change the subject, it's the polite thing to start a new thread rather than drag up an old thread that isn't even on yer topic.

Please be a little organized so you don't waste the time of helpful folks all over the world.

Thanks
John