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Matt S
01-05-2008, 08:50 AM
Hi Guys,

I just wanted some advice. I have a 1995 150 hp V6 2 litre Black Max Mercury. The oil injection has been removed before my ownership and i have no problem mixing the fuel for it.

My question is what is the best ratio, i have been using 50:1 but find it very smokey. My sister has a fairly new 15hp yamaha that is 100:1

What are your thoughts?

Noelm
01-05-2008, 08:55 AM
almost any "old" mix your own, will smoke, it is just a simple fact of life, when you have a constant oil/fuel ratio, it needs to be at the max needed for the Engine, which is not what is always needed, so the Motor smokes, do you know why the oil system was removed? and are you sure about the 100:1 on the Yamaha?

Matt S
01-05-2008, 08:57 AM
Thanks for that. Yeah the yamaha has it stamped on the side where the fuel line goes in,100:1

Noelm
01-05-2008, 09:03 AM
hhmm at 100:1 I would be thinking only the best quality synthetic Oil should be used, elcheapo oil and you will risk a lean condition at WOT (I reckon anyway)

FNQCairns
01-05-2008, 09:43 AM
Yeah what Noelm said, 50:1 is where you must stay with any tcw3 rated oil, if you do choose to go with say XD100 you may get away with 100:1????, like to hear of someones 5 year experiment.

The thing is the more stress the engine is under the more oil that is needed in real time, so the 50:1 denotes enough oil at full throttle, when cruising it's too much oil and at idle way more than is needed.

Tcw3 is a real crap specification of oil, then new oils which are effectively ski mobile/motorbike and jetski oils do a truly great job in comparison.

Your call, you could always run xd at 75:1 and feel confident - at least I would.

Lastly dealers/mechanic/past owners do some silly things to outboards once they are out of warranty, you may? find no thermostats fitted, without these it will be a smoky noisy and vibrating beast relative to with them, just a thought. Of coarse generically other things can also make a smoky engine like too rich idle mixture, over propped/overcoked.



cheers fnq

thelump
01-05-2008, 01:59 PM
I had a yammy 3 cyl 40 that was 50:1 but the CV in that size ran @ 100:1. i CURRENTLY HAVE A 115 2 STROKE MINUS OIL INJECTION AND RUN IT AT 50:1. A bit smokey to start but clears up after that.

Clyde
01-05-2008, 08:29 PM
We had two late model Jonno 30's that were a bought a year apart, one was 50:1 and the other was 100:1. There were no warnings or mention of a requirement for different oil so we ran both on 50:1.

I'd stick with the 50:1, I'd rather change a few plugs at worst then risk a major repair.

Good luck,
Clyde

Bilopete
01-05-2008, 08:37 PM
I know my Evi 35hp is a 50:1 mix but not owning any other boats before is this the "standard" petrol:oil ratio for 2 stoke outboards?

cormorant
01-05-2008, 09:06 PM
Yeah what Noelm said, 50:1 is where you must stay with any tcw3 rated oil, if you do choose to go with say XD100 you may get away with 100:1????, like to hear of someones 5 year experiment.

The thing is the more stress the engine is under the more oil that is needed in real time, so the 50:1 denotes enough oil at full throttle, when cruising it's too much oil and at idle way more than is needed.

Tcw3 is a real crap specification of oil, then new oils which are effectively ski mobile/motorbike and jetski oils do a truly great job in comparison.

Your call, you could always run xd at 75:1 and feel confident - at least I would.

Lastly dealers/mechanic/past owners do some silly things to outboards once they are out of warranty, you may? find no thermostats fitted, without these it will be a smoky noisy and vibrating beast relative to with them, just a thought. Of coarse generically other things can also make a smoky engine like too rich idle mixture, over propped/overcoked.



cheers fnq


Eeeeeeek. Never use XD100 as a premix - never is what I have been told.
It was designed specifically as a airborne oil as no fuel goes through the crankcase on etec motors. It is not a sticky oil

XD50 can be used as a premix so I am told but I still not sure it is TWC111 rated. It has a lot of the ashless components and will stick a bit more to old tollerence bearing surfaces.

Never lean off oils just because you are using a better quality oil unless the manufacturer designed it that way. More % fuel runs through jets and motor isn't tuned for that. If you were running a motor at constant known revs and load you could adjust your mix a bit if you monitered your plugs and fuel quality very closely.

Yes on premix it will smoke. Use quality quicksilver or XD50 oil and it will smoke and smell less.

Investigate why the injection was removed- a lot of commercial AB boats, water Taxis , remote locations did it for reliability as they were running flat out all the time so mixed fuel accordingly. The rest were removed as the local 2 bob mechanics didn't have a clue how to set them up or maintain them. Search and see if there was a fundamental reason for it to be removed off your model and if not see about cost of reinstating it by someone who knows how to do it properly. There were bugs with some but most are known and solved and they stop your motor carbonning up or running rich or lean etc.

BM
01-05-2008, 10:20 PM
The usual reason for removing from a V6 Merc was due to stripping the fibre gear on the crank that drove the oil pump. Engine strip to fix so most would opt for premix.

Cheers

FNQCairns
02-05-2008, 08:21 AM
Eeeeeeek. Never use XD100 as a premix - neveris what I have been told.
It was designed specifically as a airborne oil as no fuel goes through the crankcase on etec motors. It is not a sticky oil

XD50 can be used as a premix so I am told but I still not sure it is TWC111 rated. It has a lot of the ashless components and will stick a bit more to old tollerence bearing surfaces.

Never lean off oils just because you are using a better quality oil unless the manufacturer designed it that way. More % fuel runs through jets and motor isn't tuned for that. If you were running a motor at constant known revs and load you could adjust your mix a bit if you monitered your plugs and fuel quality very closely.

Yes on premix it will smoke. Use quality quicksilver or XD50 oil and it will smoke and smell less.

Investigate why the injection was removed- a lot of commercial AB boats, water Taxis , remote locations did it for reliability as they were running flat out all the time so mixed fuel accordingly. The rest were removed as the local 2 bob mechanics didn't have a clue how to set them up or maintain them. Search and see if there was a fundamental reason for it to be removed off your model and if not see about cost of reinstating it by someone who knows how to do it properly. There were bugs with some but most are known and solved and they stop your motor carbonning up or running rich or lean etc.

Thanks you could be right, I looked into it a while ago for my personal use and it was claimed to be compatable as premix from memory but have since gone cold on it due to price so am not totally sure ATM.

Will look into it again to see if my option is still open, would be a huge waste of money if it were now closed:'(.

cheers fnq