Oiled gas question.
 

Okay, I don't know, so it's time to ask the guru's..

I have a 200hp 1991 Mercury engine. It runs sweet.. nothing wrong with it, and I'd like to keep it that way. A while back I installed an electronic oil injection pump conversion so that I don't have to worry about the plastic gear breaking and the engine not getting oil and blowing up.

http://www.go2marine.com/product/112...t-systems.html

My question is, would there be any problems if I added some oil to the gas anyways.... say a 100-1 mix ... I know it would run richer, and I might foul some plugs, but would it do any harm to the engine? I've never heard of a rich running engine wiping a cylinder, and that's the thing I fear most. Spark plugs are cheap......

I am no guru.
What has the better life expectancy, a plastic gear, or electric mix pump? I understand where you are coming from 100%.
To the question:
Ferman was just telling me about potential damaging effects of running too much oil. I do know that outboards to run hot with all the extra oil. It also dilutes the effective octane of the fuel your mixing the oil with. Taken to the extreme the motor could pre-detonate if the octane gets too low and wipe a piston. My theory has always been, why would the manufacturers recommend 25:1 on break-in if it was harmful to the equipment? Or was that the old way? I always pre-mixed slightly over-oiling on a 40:1. In an older carbed motor the most important thing is clean fuel and regular use. No amount of oil will do it any good if the main jet on one of those six carbs catches a bit of debris, or you stick a needle, game over..

carbon buildup is your enemy, excess oil will increase the amount of carbon in your engine, run ring free or carbon guard, decarb your engine regularly and try amsoil 100-1 synthetic to add to your gas for insurance

If your going to add oil to your fuel for insurance, why wouldn't you just pre-mix it and be done with the oil injection? It only takes a few seconds more time to mix it 50:1 than it does 100:1, then you don't have any worries about it being oiled properly.

These engines have a rep for breaking the plastic gear on the crankshaft that drives the VRO pump and then blowing up due to lack of oil. But the also have a great rep for being a strong, fast engine when they are working properly. And it seems that no one (including Mercury) has ever made a replacement metal gear. That's why this company came out with the electric driven oil pump. As to the reliability of the electric driven one, with only one season under it's belt, really, I don't know. It looks like a quality unit, and it seems to be working fine. Only time will tell.

If I went premix, there's always the possibility that I'd screw it up one day and not add the proper amount of oil, which is what I'm trying to avoid. Plus, I have a 4 stroke kicker engine that I was contemplating using. So I was thinking I wouldn't have to carry an external fuel tank for it. You're right, going premix is probably the best solution... Hell, I don't know, that's why I was asking here.

I use Amsoil in my cars and trucks. Costs more, but to my way of thinking it's well worth it. Good answer on the carbon build up. That's something I can understand. Thanks. Guess I'll run with straight gas, carry some 2 stroke oil for insurance, and pray for the best.

To everyone: THANK YOU ALL for the answers!! The reason I ask questions is to learn, and these forums are simply one of the best classrooms I know of. :beer:

My boat not having an oil reservoir, when I installed my 94 Evinrude two-stroke I removed the fuel/oil VRO pump and replaced it with a fuel only pump, capping off the oil inlet to the engine but leaving all of those hoses in place. I premix 50:1. It smokes a lot and I hear the phrase Better Smoke than Broke a lot.

I wonder, since I very rarely run wide open... do I really need 50:1? Isn't that pretty much WOT ratio? Shouldn't I be able to mix 40:1 and be fine and result in less carbon build-up? Doesn't the VRO pump somewhere around 150:1 at idle and 50:1 wide open? What would be the worst case scenario if you were mixed at 40:1 and ran WOT for, say, 5 minutes?

40:1 is richer on oil than 50:1. The VRO is designed to oil around 40-50:1 at WOT(depending on the size of the engine, larger engines pull more fuel and thus the pump richens up the oiling more), and drops down to about 75-100:1 at idle. I've rejetted several engines now to run on pre-mix, and if you run GOOD quality oil they don't smoke bad at all running 50:1 premix. MERCURY QUIKSILVER oil has been the WORST oil I have used as far as smoke goes, and PENNSOIL blend has been the best to keep the smoke down. i'm not a PENNSOIL fan myself, except for 2 stroke oil. In which case I use it in EVERYTHING. Every boat I work on, have owned, and any 2 stroke engine I have or worked on right down to lawn equipment gets it.

Yeah I guess I meant 60:1, lol. Sounds like the recc is to use the pen soil and stick with 50:1, though. Thanks

I expect that pump will last a while, but my neutered engine will NEVER have a low oil issue. Mixing 50 to 1 is as easy as it gets. just as easy as filling 2 tanks. Only trouble I have is pulling a shrimp trawl, after a couple hours it will carbon up, just a short run clears things up though.

Never heard that about quicksilver oil, I use it or Castrol, any opinions on Castrol 2 stroke oil?

In my more than 40+ years of boating I've mixed thousands of gallons of premix, everything from 20 - 1 for my British Seagulls to 50 - 1 for my neutered 225 Johnson, and I'm not even going to count the endless chainsaws, snow blowers, string trimmers, etc., etc. One of the BEST gadgets I ever bought was a premix plastic bottle from Walmart (http://www.walmart.com/ip/Shoreline-...ottle/17128586) that shows you how much oil to mix for whatever amount of gas you want to use. Less than $5 and I never make a mistake on the proper ratio. I know that premixed gas will never give me a low oil issue.
BUT
There's a reason that manufacturers put VRO pumps on outboards. They cost money to make and install, and for whatever the reason, they are there for a reason. That being said, I have my own reasons for desiring to not premix if possible and if it's safe for my engine(s). My main engine is a 2 stroke, but my kicker is a 4 stroke. I'd like to run them both from the same tank so I don't have to carry extra gas cans. What's good for me might not be good for others.