pre-mix ratio

[bigmotor]

just got a new rig with 2.4 efi's big horn style not the bottom feeders,
it's set up for pre mix,and I'm wondering what to mix it at .
50:1 ???????
Don't want to get it wrong!!!!!!!!!!!!!!!!!!!!

[capnzee]

If you are going to run it hard, I wouldn't even run pre-mix! You have no idea of the quality of oil in the pre-mix, they certainly won't mix the best oils such as Mercury, OMC, or Yamaha. 50:1 is the normal mixture recommended by most manufacturers today and should suffice for engines running at their rated RPM's (6000 or below). If you are going to run for long hours at WOT or near the 6000 or more RPM I would consider mixing the fuel:oil a little richer, edging towards 42:1. Capnzee

[bigmotor]

What I'm getting at is the motors are not oil injection,so I have to mix the gas/oil each time I fuel up.
Sounded like you where reffering to some thing else???
I would like to have the motors safe ,with out smoking out the whole lake .

[Stretch]

I think capnzee was talking about the goofball at the gas dock who might not be very good at math.

[MERCing]

Some older marinas used to have "Pre-mixed" pump gas. Haven't seen one in awhile but that may be what Capnzee was refering to.
On fishin' motors(running below 6000 rpm's) I used 50:1.
I pre-mix for my Super Mag and run it over 7000 rpm's sometimes and I mix it at 40:1.

[bigmotor]

Downriver area -Trenton- Running the boat on Lake Erie,Detroit river,and once in a while take a ride up to lake St.claire.
We take run's to "Put-in-Bay" every now and again.

[Hank W]

40 to 1 under 8000
32 to 1 over 8000

[Hack02]

Good advice from Hank W. My Merc manual says 32-1 for my 96 260. I've been running 36-1 for years with good results. Thats a good looking boat you 've got there.

[david laser86]

32/1 will smoke you out. I feel 40/1 is plenty oil for any lake motor 8000 rpm's and under.
Dave. :cool:

[Raceman]

I run full synthetic at 32:1 in all of my stuff and I've lost 2 powerheads in almost 30 years of running Merc V6's, one with somebody else's fuel & oil, and one when an oil injection pump failed, so you might say the track record is 100%. It IS TRUE that 32:1 smokes a little more, (but not enough to matter) and also that 40:1 may be adequate, BUT with no other downside I like the extra insurance. I wouldn't even consider 50:1 in that engine REGARDLESS of how hard you turn it.

Also............... I ALWAYS run Super Unleaded in my stuff and think you should with that engine also.

When Merc first introduced the V6 race engine in 1976 the recommended ratio was 18:1 and it was published in the catalogues. For MANY YEARS I ran 24:1 in even my stock engines, as did most of my friends................. "double oil" as we called it then, since the factory recommendation was 50:1. The early 1750's had some failures, but we never lost one. Only reason we came up on the ratio from the 24:1 is the belief that today's synthetics are a lot better.

[ken medendorp]

Also I beleive you have better rings seal with more oil you just have to richen you air to fuel mixture because with more oil the fuel dosen't flow thru the jet's or injector's as fast

[capnzee]

Sorry guys, when I hear the words PRE-MIX, I immediately think about the marina pumps that are set up to automatically pump a gas/oil mixture at a ratio of 50:1 or there-a-bouts. We actually have one of these dinosaurs at Frentress Lake in East Dubuque, Illinois. I have removed all of the oil pumps from my v-6's and have a 2002 60 hp Merc on a light aluminum flat with oil injection. I still mix oil with my gas in addition to the oil injection on that engine. As I understand the oil pump monitors oil to the engine at 50:1 only at WOT, at idle it is closer to 100:1. In my day, the day of the Hurricanes and Thunderbolts, powerheads were bullet proof, we mixed at 24:1. Going through the used marine engines in todays newspapers, I notice too high of a percentage of used engines advertising "NEW POWERHEAD/POWERHEAD OVERHAULED" etc. Whats wrong here--I say the factory oil injections systems SUCK! Capnzee

[pyro]

40:1 in your Bridgeports.

I mix my fishin' motor gas (Xri like yours) at 40:1 also.