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Thread: Too much oil

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    Default Too much oil

    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.

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    Sabine River Gang Riverrat001's Avatar
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    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.
    Poor Boy Racing

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    Administrator Ron Hill's Avatar
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    Default PERSONALLY, I Don't Think You Can Use Too Much Oil

    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.

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    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

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    Team Member zul8tr's Avatar
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    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.
    " Three may keep a secret if two of them are dead" Ben Franklin
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    Administrator Aeroliner's Avatar
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    Default Never to much oil

    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

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    Quote Originally Posted by zul8tr View Post
    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.

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    Team Member zul8tr's Avatar
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    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.
    " Three may keep a secret if two of them are dead" Ben Franklin
    " ------- well Doctor what have we got a Republic or Monarchy? A Republic he replies if you can keep it"
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    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.

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    Default oil ratios

    Quote Originally Posted by Nason View Post
    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!!

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