Premix vs Oil Injection

[rustyscrew]

I recently purchased a boat with an old 1978 Mercury 1400. It requires a 50:1 mix of oil. I am wondering if anyone had thoughts on whether I can install an aftermarket oil mixer that will pull from a resevoir of oil and mix it before the engine. I understand that pre-mixing at 50:1 accomodates the higher end performance, but that much of the time only 100:1 is needed.<br /><br />Any thoughts on this?<br />Any recommendations on some good units?<br /><br />thanks<br />jared

 

[JB]

Re: Premix vs Oil Injection

No way would I consider adding oil injection to an engine that was designed to use premix, Jared.<br /><br />Adding oil injection to a later model engine on which it was an option originally would be a different matter.

 

[WillyBWright]

Re: Premix vs Oil Injection

There are no reliable add-ons. Merc offered AutoBlend, but parts are hard to find and expensive if you can. Also prone to failure. 50:1 is required for proper lubricatrion at higher RPMs. 100:1 is adequate for those that idle around all the time ... like kickers. I'm afraid you're stuck premixing at 50:1 ... like me.

 

[rustyscrew]

Re: Premix vs Oil Injection

Thanks for the rapid response. Sounds like I am going to be pre-mixing. Oh well, figured it was worth a shot.<br /><br />cheers.

 

[JC1933]

Re: Premix vs Oil Injection

Hi Rustyscrew <br /><br /> You might check into OMC Accumix R they seem to work very well, and should work on Merc. they are still available through Bombardier. Have a nice day.

 

[WillyBWright]

Re: Premix vs Oil Injection

Years ago those were only for twins and no more than 50Hp. They may have upgraded them, I dunno. If so, that would be my choice.

 

[rustyscrew]

Re: Premix vs Oil Injection

I'll let you know what I find out about accumix. I am going to try and get the boat in the water for next week.<br /><br />thanks

 

[marinemech1]

Re: Premix vs Oil Injection

keep mixing 50:1 why complicate an easy system only part the can screw up is the nut behind the wheel

 

[dajohnson53]

Re: Premix vs Oil Injection

Originally posted by marinemech1:<br /> keep mixing 50:1 why complicate an easy system only part the can screw up is the nut behind the wheel

I'm wondering - statistically - which is more reliable, the human mixing 50:1 or current versions of the major manufacturers' 2 stroke oiling systems. Probably doesn't have anything to do with this particular issue - but in general.

 

[crazy charlie]

Re: Premix vs Oil Injection

I have 100% trust in ME.Thats why I eliminated the oil injection on my 150 Ocean Pro.

 

[rodbolt]

Re: Premix vs Oil Injection

funny you ask<br /> in the almost 30 years I have been playing at this I have actually seen more motor failures caused by oiling or lack of, in premix motors. the nylon gear and the first 2 years of omc VRO. we wont disscuss economixer.<br />for tiny mites premix is ok, trying to mix oil consistantly 150+ gallons at a time is awkward.<br /> when I rebuilt my 112spl last week I added the OMS kit to it. I hate mixing the twin builtin 18 gallon tanks.

 

[dajohnson53]

Re: Premix vs Oil Injection

Having done a lot of premixing in both portable and built in tanks, I have come to the conclusion that premixing isn't as fail safe as everyone makes it out to be. Thats why I made the comment / question of whether statistically speaking, premix really is more reliable than tried and true, modern, premix systems. I know it seems to be "conventional wisdom" that premixing is fool proof and safer, but I kind of doubt it.

 

[JB]

Re: Premix vs Oil Injection

Injection systems are insurance against human error (except forgetting to keep the oil tank filled). Most of them use less oil than premix without endangering the engine.<br /><br />Premix is insurance against failure of the injection system.<br /><br />Take your pick.

 

[Solittle]

Re: Premix vs Oil Injection

1 gallon of tcw3 to 50 gallons of 87 octane is hard to screw up.

 

[dajohnson53]

Re: Premix vs Oil Injection

Yea tough to screw up in theory. But it happens, and especially when you're dealing with built in tanks, partially filled - and you don't know how much fuel they will take until you're done pumping.... and with normal distractions on hand. I don't think I ever screw up, but I have indeed probably doubled the oil a couple of times because I wasn't absolutely sure I'd added oil. I'm just saying that even though you may think it's hard to screw up, any time a human is involved, mistakes will happen, period. I am still curious about the reliability of human vs. the machine. Just a theoretical question, mind you, because I really don't believe either is significantly prone to error or failure.

 

[Solittle]

Re: Premix vs Oil Injection

D. This question is like a coin and has two sides. Yes we will screw up and either forget the oil or double it. On the other side a hose will break, a pump will fail or an alarm will crap out. As for me I have more confidence in what I will do than the machinery. <br /><br />Technology come into play also. If I were able to afford a new engine I would not pre-mix. However all of the engines that I have owned have been relative old timers (like me I guess). My two fairly well maintained 110s are salt water engines and 19 yeard old.

 

[dajohnson53]

Re: Premix vs Oil Injection

Indeed. I have the same vintage engines as you - old, reliable, well cared for, premixed. But I'm the type of guy who disproves any "fool proof" system.

 

[rustyscrew]

Re: Premix vs Oil Injection

Thanks for all the feedback. In the end, just to keep it cheap I am sticking with pre-mix. The best benefit that I could see of oil injection would be if it could make the mixture leaner at low rpms so I wasn't blowing a blue cloud in the harbor!

 

[dajohnson53]

Re: Premix vs Oil Injection

Originally posted by rustyscrew:<br /> ...if it could make the mixture leaner at low rpms so I wasn't blowing a blue cloud in the harbor!

That's another interesting issue rustyscrew. I have a large main engine and a small kicker - both very old. I have two built in tanks and pre-mix at 50:1, and run both engines off them (I figure with dual tanks and a water filter, I have the redundancy I need for a reliable fuel supply). I've often thought: "why not keep a small tank of 75:1 or 100:1 to run the kicker when I'm trolling?" My thinking is that the leaner mixture wouldn't hurt the kicker when trolling, and might be less smelly and smoky. I never run the kicker at beyond trolling speed - but if I did (for instance if the main failed and I had to get back to shore, I could easily hook up to the built in tanks with 50:1. Just another thing to have on hand laying round the back of the boat though.

 

[rustyscrew]

Re: Premix vs Oil Injection

I also have 2 tanks and I thought about that idea of using 1 for 50:1 and the other for 100:1 but I figure its a recipe for disaster- due to my own forgetfulness. However, that is a good idea to just bring an auxillary can of 75:1 for the trolling kicker. I just spent the weekend trolling for salmon and breathing fumes!