Too much oil

[Nason]

Is it possible that too much oil will kill your rpms ?
I'm trying to set up a new built motor but the rpms are not coming around, the oil i'm using is R50 16 oz to 5 gallons gas. I tried this mixture on my stock motor and I lost about 300-400 rpms, on Mercury oil TCW3 16oz to 6 gallons gas it will turn 6100-6200 rpms.

[Riverrat001]

Try the klotz outboard techniplate instead of the r50. The r50 is for high rpm motors. The r50 has better corosion inhibitors for storing your motor though. At least that's what I've gathered from researching it.

[Ron Hill]

I have friends that their kids are still running 2 quarts of oil to five gallons of gas. And they are winning Championships.

As I undertand it, more oil LEANS the air to fuel mixture. Too much oil could be leaning your engine out.

I had a 402XS (33.3 cubes, One third of an in lines six), when I ran two quarts to five gallon it would run along and then load up, and actually blow "Smoke Rings" as I went down the straightaways. I had to run less oil to get it to run clean. What fixed this "OIL" problem was to run "Gapped" plugs, I had been running "Surface Gap" plugs.

Also, I was using PETROLEUM OIL, not synthetic. Petroleum oil does not burn. Synthetic oil burns.

[Powerabout]

Nason thats 40:1 and 47:1

rule of thumb is you should make more power right up till about 20:1
OMC and Merc recommended race engines to run at 25:1
you get better ring sealing hence more power and safety

I wonder what the relationship is between burning and leaving carbon deposits?

I wonder if you fuelled a diesel with 2 stroke oil, would it would run?
When the turbo oil line breaks and sprays a hot turbo we know what happens to oil....

If oil exited a e-tec it would never pass the EPA regs
flash point of tcw oils is about 212f . Makes cheaper handling?
L'm sure its hotter than that in your combustion chamber and there is already a fire

[zul8tr]

What engine do you have? What is it running on? What rpms are you wanting to get to? As "Powerboat" notes the mixes you are using are 40 and 47:1 which are not oil excessive.
Race engines that I have read about here, on Hydroracer, in PM's and elsewhere state as rich as 9:1 to about 40:1. As stated above more oil helps seal the rings for more power which is corroborated by tests down to about 18:1. Usually excessive oil also is to let parts live longer, and as has been stated oil is cheaper than parts. Higher rpm requires more oil.

[Aeroliner]

We run a number of classes in NBRA and have been running a 12 :1 mix for some time. Normally we run our Merc's at 8,300 to 8,600 RPM. Our standard setup uses the Mercury magneto and J-4-J Champion spark plugs. We have been using Castrol TCW-2 only because I had 100 gallons of it. We have not had any oiling issues doing this. One thing to remember that the more oil you add to the mixture the greater the BTU content will be pound. Like Sam said the mixture might require adjusting. We use needle valve carbs so we adjust to get best performance. Fixed jets might be in need of change if your setup that way.

Alan

[Nason]

What engine do you have? What is it running on? What rpms are you wanting to get to? As "Powerboat" notes the mixes you are using are 40 and 47:1 which are not oil excessive.
Race engines that I have read about here, on Hydroracer, in PM's and elsewhere state as rich as 9:1 to about 40:1. As stated above more oil helps seal the rings for more power which is corroborated by tests down to about 18:1. Usually excessive oil also is to let parts live longer, and as has been stated oil is cheaper than parts. Higher rpm requires more oil.

The motor is a merc 40 hp triple 59 ci that has been cut on. The boat is a 15 x 48 weld built, I would like to reach 7500 - 7800 rpms.. The motor is just broken in and I'm trying to fine tune it. From 0 to 6500 rpm its pretty quick but kinda slow getting to 7000 rpms.

[zul8tr]

So not a race boat, is weld built aluminum? A 15 x 48, is that ft x inches wide? Easy to reach 7500+ rpm just reduce pitch and diameter but no guarantee that it willl be the correct prop for the set up and you just have an over reved engine and poor speed. You need to sneek up on the correct prop for your setup for the rpm and speed target. For each prop try different heights and different prop shaft angles, record results of speed (gps ideal, water pickup next best) and rpm. Run in 2 directions. Check out in turns. Record oil ratio and fuel using. Try different oil ratio and see what happens. Does the carb have adjustable high speed? Speed usually increased with increased height and correct shaft angle, there is a limit for each prop for a specific hull and water conditions. You need to find that limit.

You can estimate prop slip knowing rpm, speed, gear ratio and pitch using:

http://continuouswave.com/cgi-bin/propcalc.pl

If you can get 5% or less you are doing excellent but, I expect you will get to the near 10% slip performance unless you have a very light hull that you can get a lot of it out of the water to reduce the water drag.

Repeat with a different prop

Tedious work no easy out here.

[BRzuki]

You need my little merc chopper in the classifieds Nason! Put a hub in it and 7500 shouldn't be any problem once the motor loosens up a little.

[champ20B]

Is it possible that too much oil will kill your rpms ?
I'm trying to set up a new built motor but the rpms are not coming around, the oil i'm using is R50 16 oz to 5 gallons gas. I tried this mixture on my stock motor and I lost about 300-400 rpms, on Mercury oil TCW3 16oz to 6 gallons gas it will turn 6100-6200 rpms.

I always use pennzoil 2-cycle. It is just a good oil from my experience.
I have a Champion 6NHR Hot-Rod outboard (20 cubic inch) and it requires an 8:1 ratio. Thats right, 8:1, and thats alot of oil. But one thing to consider though is that it uses 18mm plugs "the big kind". That probably makes a difference in regards to fouling. My 1939 Evinrude 16.2HP sportfour requires the same ratio (for high speed operation) and also runs 18mm plugs. They both run very strong though. With its optional 2 blade Stannus propeller, the old Evinrude 16.2HP four cylinder would outrun my Mark 25 Mercury by about 2-MPH! Thats pretty wild!!

[Fastjeff57]

Taken to the extreme--more oil than gas--one would end up with a low octane "fuel" that would cause severe pre-ignition. Going richer and richer approaches that condition, right?

Jeff

[Powerabout]

if we assume the oil doesn't add to combustion?

[champ20B]

Taken to the extreme--more oil than gas--one would end up with a low octane "fuel" that would cause severe pre-ignition. Going richer and richer approaches that condition, right?

Jeff

Thats a good question. I thought about that a long time ago myself. However, from my experience with various old outboards, I have never seen or heard of anything like this occur. I believe that this could happen if you go beyond a certain point. For example, one pint of oil in one gallon of gas is not going to affect its performance noticably, although that is 8:1... But if you mix it 4:1 or more, wierd stuff might start to take place. My brother and I have a 1997 model 35HP Johnson (3 Cylinder), on a 14ft center console boat. I removed the variable-ratio oil premix system and went to the old premix method a few years ago. We run it at 32:1 opposed to the 50:1 it requires. It runs absolutely perfect and has not had any fouling issues at all. Acceleration is very crisp and start-ups are immediate every time as we never had any trouble with it .

[Gene East]

I agree with Ron on oil mixture. I used to mix 2 qts. Mercury oil to 5 gal. of gas in my 20-H 50 years ago. Used plain old J-4-J plugs. Never had any fouling problems, certainly never burned any bearings, plus I won a race or two. Remember, most mechanics know more about the need to lubricate than anyone at the EPA. Never trust anyone from the government!

[Aeroliner]

In my old 20-H racing days the Mercury was run at 16:1 if I recall correctly. Back then we were running regular mineral oil and synthetics were only available quite some time later. If I remember correctly the oil was about 30 weight. Today in our racing program we run 10:1 in our C,D and E MOD Merc's using Castrol TCW-II which is a synthetic and also quite thin compared to the old Mercury oil. We also run magnetos on all our engines and champion J-4-J plugs without any issue of fouling. When looking at the fuel mixture I believe that the more oil used up to a point provides more power. This was found during our testing when we look at the GPS speed. The density of oil is greater then that of gasoline so in theory you get more BTU's per gallon with a heavier mix. When we look at octane rating we usually run 93 with no alcohol which is more then enough with the heavy oil mix to meet the compression requirements of our engines. For a time while the NBRA had a sponsor we were running fuels with alcohol in them with no issue also.

Alan

[omcstratos]

This is a little bit apples to oranges but anyway... When I was a lot younger, I had a 2 stroke weedeater type of motorized scooter. I messed around with that thing seeing what all it would do. I liked two stroke smoke and thought it would be cool if I ran it on straight 2 cycle oil. It smoked like crazy and had to keep the choke partially closed for it to idle. Other than the spark plug fouling pretty quickly and raw oil going through the exhaust, it seemed to run pretty well.

Also, before my time, one of our family's fishing motors was a mercury 10, I'd guess from the mid 50's. The motor was rated for 25:1 and I think that was because 2 cycle oil was really just a quart of motor oil. The oil doesn't mix as well with gas as tcw3 oils do so they had to up the ratio and that motor ran perfectly fine, Even outran our newer evinrude 18 later on.

Now after my rant, The main "thought" about mixing a heavy oil ratio would be lowering the octane rating in fuels right. Ok, then I would think that "back in the day outboard oil" mixed at 25:1 would lower the rating much more than tcw3 at 25:1 and those motors are still around.

[omcstratos]

This is a little bit apples to oranges but anyway... When I was a lot younger, I had a 2 stroke weedeater type of motorized scooter. I messed around with that thing seeing what all it would do. I liked two stroke smoke and thought it would be cool if I ran it on straight 2 cycle oil. It smoked like crazy and had to keep the choke partially closed for it to idle. Other than the spark plug fouling pretty quickly and raw oil going through the exhaust, it seemed to run pretty well.

Also, before my time, one of our family's fishing motors was a mercury 10, I'd guess from the mid 50's. The motor was rated for 25:1 and I think that was because 2 cycle oil was really just a quart of motor oil. The oil doesn't mix as well with gas as tcw3 oils do so they had to up the ratio and that motor ran perfectly fine, Even outran our newer evinrude 18 later on.

Now after my rant, The main "thought" about mixing a heavy oil ratio would be lowering the octane rating in fuels right. Ok, then I would think that "back in the day outboard oil" mixed at 25:1 would lower the rating much more than tcw3 at 25:1 and those motors are still around.

uhh, that might have been going off on a rabbit trail.

anyways, a lot of the production race motors are rated at 25:1 from the manufacturer. sst45, I think mercury 44xs, I think there was a study that from 50:1 it helps make more power as you increase to 18:1 due to sealing up the rings. More oil than that you begin to go backwards again.

[zul8tr]

uhh, that might have been going off on a rabbit trail.

anyways, a lot of the production race motors are rated at 25:1 from the manufacturer. sst45, I think mercury 44xs, I think there was a study that from 50:1 it helps make more power as you increase to 18:1 due to sealing up the rings. More oil than that you begin to go backwards again.

Lots of racers use more oil than 18:1 (like 8:1) and have fast running rigs. Right on the better sealing of the rings, and the bearings live longer at the higher revs.

[champ20B]

Thats a good question. I thought about that a long time ago myself. However, from my experience with various old outboards, I have never seen or heard of anything like this occur. I believe that this could happen if you go beyond a certain point. For example, one pint of oil in one gallon of gas is not going to affect its performance noticably, although that is 8:1... But if you mix it 4:1 or more, wierd stuff might start to take place. My brother and I have a 1997 model 35HP Johnson (3 Cylinder), on a 14ft center console boat. I removed the variable-ratio oil premix system and went to the old premix method a few years ago. We run it at 32:1 opposed to the 50:1 it requires. It runs absolutely perfect and has not had any fouling issues at all. Acceleration is very crisp and start-ups are immediate every time as we never had any trouble with it .

One thing I want to say about 2-cycle oil, is that you have to be mighty careful which oil you choose. I had a 3.5 Chrysler air cooled outboard (like a west bend type), that I ran 16:1 in. I used the ashless TCW3 junk. One day I was trolling in a bayou for speckled trout. Next thing, my bearings started squealing, then it siezed up. I also had a mishap, because of this, with my Evinrude 9.7 Lightfour. The rotary valve stopped sealing and it would not run right. It started spitting feul back out of the carburator. I mentioned this on another post, as to avoid the "clean type" oils. The way I tell a good oil from bad is simple. I smell it to see if it has a soapy/mothball type oder. If it does, I avoid it. If it has just a kerosene/oil odor, it 's probably good. Next I put a dab on the tip of my index finger and rub with pressure against my thumb. If I feel a slight bit of grip(traction) with a stop/go action of sliding my thumb and finger together, the oil has sorry lubricating quality. I avoid it. If there is only slippage with no traction, it is a good oil.