ondarvr
Supreme Mariner
- Joined
- Apr 6, 2005
- Messages
- 11,527
Re: OMC 100:1 mix ratio retract to 50:1 question
[qoute russellmead10]
My general practice;
I run 40:1 to 50:1 for general use (more oil first tank of season or higher temp/heavier boat load)
75:1 if primarily trolling & low speed
100:1 if basically entirely trolling my skiff for endless hours (reduces plug fouling)
40:1 to 25:1 with extended Wot running, like 50-100mile endurance runs between 3/4-Wot except for fuel stops (also change to non-gapable high speed spark plugs (like common in many of my other small merc's)). Not sure how many 100's hours I've put on the Johnson 15, but it still starts every time and pumps out plenty of power.[/QUOTE]
Like already stated, this sounds like a lot of work for little or no gain.
1. What does running 40:1 in the first tank of the year do to help anything?
2. In forty+ years of boating I have never fouled a plug, so how is it going to be reduced by going to 100:1.
3. 25:1 to 40:1 for high RPM. Nobody recommends this for any stock OB even running at WOT, where do you get the idea this will help? (I'm talking engines recommended for 50:1)
4. When you fill the tank how do you know exactly how that entire tank will be used? You will possibly be trolling, cruising and running WOT all in the same day, do you switch tanks?
Did you know that your jetting changes with oil ratio, as you add more oil you will run leaner, less oil richer. So you should be changing the jets while you're at it.
The engineers that get paid to make sure these engines run correctly for many years have determined that 50:1 seems to be the best ratio to cover all types of uses. I'm sure many here have far more experience and knowledge on the subject though (sarcasm).
Yes oil infection ratios vary by RPM and throttle position, but you can't control any of this when using premix. It seems like a good way to outsmart yourself and while gaining nothing, risking a great deal.
[qoute russellmead10]
My general practice;
I run 40:1 to 50:1 for general use (more oil first tank of season or higher temp/heavier boat load)
75:1 if primarily trolling & low speed
100:1 if basically entirely trolling my skiff for endless hours (reduces plug fouling)
40:1 to 25:1 with extended Wot running, like 50-100mile endurance runs between 3/4-Wot except for fuel stops (also change to non-gapable high speed spark plugs (like common in many of my other small merc's)). Not sure how many 100's hours I've put on the Johnson 15, but it still starts every time and pumps out plenty of power.[/QUOTE]
Like already stated, this sounds like a lot of work for little or no gain.
1. What does running 40:1 in the first tank of the year do to help anything?
2. In forty+ years of boating I have never fouled a plug, so how is it going to be reduced by going to 100:1.
3. 25:1 to 40:1 for high RPM. Nobody recommends this for any stock OB even running at WOT, where do you get the idea this will help? (I'm talking engines recommended for 50:1)
4. When you fill the tank how do you know exactly how that entire tank will be used? You will possibly be trolling, cruising and running WOT all in the same day, do you switch tanks?
Did you know that your jetting changes with oil ratio, as you add more oil you will run leaner, less oil richer. So you should be changing the jets while you're at it.
The engineers that get paid to make sure these engines run correctly for many years have determined that 50:1 seems to be the best ratio to cover all types of uses. I'm sure many here have far more experience and knowledge on the subject though (sarcasm).
Yes oil infection ratios vary by RPM and throttle position, but you can't control any of this when using premix. It seems like a good way to outsmart yourself and while gaining nothing, risking a great deal.
