TOPIC: To mix or not to mix.

Happy New year Boat nuts, er, enthusiasts. Every since I was a kid, racing mini hydros and mixing oil n fuel for the ol Mercury Mark models I used to have, I never gave it a second thought. Pre-mix is a part of life. But now I have an 88 Mercury 90 hp 3 cyl with oil injection . Its not one of the ill-fated AutoBlend systems or the real late system with the plastic gear thats prone to failure. Mercury calls this one Advanced oil injection. Ive heard n read that the system is bullet proof and works really well and is dependable. But for the life of me I just cant bring my self to fill the tank with straight gas and start the 90 up,much less take it for a ride on straight gas. Its an 88 Ive only had it for less than a year so its been running for what 27 years with oil injection and no damage. I checked it when I got it and there was straight gas in the tank,I checked the oil injection to make sure it worked and it did just fine. I made a 50:1 batch and took it out to the river for the first time Id ran it and it didnt seem to smoke too much.Im too old to change. I cant run it with with straight gas, I just can t.It seems -- just wrong.Im thinking this season on mixing real light oil ratio 70:1 or the like.And let the pump do its thing. Anyone else have this same problem?

I would go ahead and use it with the system in place. You've confirmed that it is working, so why change it?

Oil systems had their issues, but they were quickly remedied. Unfortunately, they are blamed for many issues for which they are not at fault. This leads to many folks condemning them and contributes to the myth that they don't work well.

I'm with you, not much trust in oil injection systems. If you decide to use it, adding a splash of oil to the gas will give you peace of mind, and maybe prevent meltdown if the oil pump fails at speed. 100:1 mix is not too heavy and will get you to the dock if you take it slow. A bass fishing friend does this, and keeps a quart bottle of oil on board to add if doodoo happens. He loves oil injection, but doesn't trust it fully.

Many years ago I got a Yamaha Blaster on a trade. It was a very nice RACING quad for the time. It had it's engine built as far as boring and stuff allowed. Why had it been rebuilt? The auto oil system failed I was told. So I mixed it myself and had a ball with that thing. It had my fat ass up to 70 mph before I chickened out. I do not know other than once being run low on oil I was going to see to it that it did not happen again. After all the quad was a bare-bones very light quad. What made value was in fact that it had a racing engine with aftermarket racing carb, ignition and innards. I remember riding it and came across a family riding. The younger boy was looking over the quad and blurted out. "Man for an old man you ride a cool quad." We all broke out laughing.

Robert, it's that santa claus beard.

Just seal off, disable any the VRO, and add oil to the gas. Worked fine that way decades, and to me its a answer for a question never asked. Just a different way to do the same damn thing. They DO work, but if ya want to go back old school? Do it. Peace of mind way better than a "worry".

I had an RD350 Yamaha with chambers. It was a screamer, in more wats than one. It had injection but I mixed about 70:1 in the gas and picked up over a 1/10th in the quarter and didn't hear the pistons slapping as bad And I LOVED the smell of all that smoke.

Yeah its just a personal problem.Cant get past it. Ill mix it 70:1 and should be okay, I wont worry then. But for what its worth Ive heard, read n been told the advanced injection is bullet proof and they do work well for years and years. I guess so, mines an 88 and still going strong. Like I said its a personal problem I have to learn to deal with these new fangled modern cornvienences. Happy New Year to you all and drive/be safe tonite see you next year fbrfrm65

If you just cant trust the oil injection, disconnect it and run straight mixed gas.

Adding excess oil to a working oil injection system, IMO, has no up side. Excess oil fouling plugs, carbon loaded cylinders, higher viscosity oil thru the jets, more oil by volume in a given amount of combined fuel and oil reduces the amount of fuel which could lean out the motor, if nothing else that reduces efficiency of the burned fuel.

If/when the injection system fails, at anything above a no wake idle, is 70:1 sufficient to adequately protect motor?

Point well taken, but (and this a crucial but)if I disconnect it, the pump will be running dry and after a while it,well that cant be good. If I sell the motor some day and new owner wants it as the god KEIKHAEFER meant it to be then I need to leave it alone.Yes, I think 70:1 will work with some care. I seldom run for long times at WOT. Im more a half, three quarters throttle cruiser ,see the sights ya know. 70:1 isnt that far from 50:1 either.I race with my buddies once in a while but mostly my motors have a pretty easy life. This just occured to me. I mix up a batch of 70:1 Then the pump delivers 50:1 fuel mix to the top carb thats already getting 70:1 fuel. Do s that make it 20:1 after all said n done? Thats way to heavy a mix and yeah, then we are talkin fouled plugs, carbon and all that at 20:1.Confusing aint it? I need to buck up clench my teeth fill up with straight and let the chips fall where they may. But I just cant do itArrrrrggghhh. So how many of you all run with oil injection.? How many? Please chime Y or N using it. fbrfrm65

I have always had older motors that need premix until my dad bought a new pontoon boat in '89 with that same 90 hp motor only a year newer. We have put a lot of hours on it using the injection with no problems. There is an alarm that sounds when the tank starts getting low. We always keep a jug of oil in the boat, but the alarm gives you plenty of time to safely get back. In a pinch, if the pump quits working we can always dump some oil in the tank to get back as long as you shut it down in time.
Bill