100:1

[EASLOOP]

Yikes! I have acquired an older Suzuki 2.2 2 stoke o/b and I have been running it on 50:1 fuel mix. Today i dug up on the internet what may be sales blurb for that now discontinued motor but it says to use 100:1 mix. Can anyone confirm the correct mix? If it should be 100:1 could I have damaged the motor? I have noticed that if I open up the throttle under load the engine starts to falter, could this be becasue of a too oil rich mix?
All replies gratefully received.

 

[jerryat]

No damage at all, in fact you have been doing it a BIG favour!! I have NEVER run my 100:1 'eggwhisks' on 100:1 since a couple of outboard engineers told me years ago that they'll last a LOT longer if you use 50:1.

I'd stick with the higher oil content if it was my engine! /forums/images/graemlins/smile.gif

 

[Lakesailor]

100:1 is the ratio for all those Mariner/Suzuki/Mercury/Yamaha models.
They are made by Tohatsu, the biggest outboard manufacturer in the world. Doubtful it will have damaged it, but the plug won't be the cleanest around. Try a tank of 100:1 and a new plug..

 

[Cliveshep]

I bought a new Mariner 4 years ago, "run in on 50:1 and thereafter on 100:1" it said in the instructions. However, long before runnning-in was completed I was told to keep it on 50:1 by an engineer who said that too many came back with problems caused by insufficient lubrication. No running problems at all on even old (i.e. last year's) 50:1, so if yours is faltering I'd get the carb/jets all blown out and cleaned out as with such small jets even a globule of oil can cause them to choke up, lose power or mis-fire.

 

[graham]

If it runs ok on 50:1 I would keep it on that. Some outboards recommend 100:1 for leisure use but 50:1 for commercial use.

Spray a bit of Carb cleaner into the air inlet now and then if your worried about it gumming up,also allways run the ngine until the carb is empty after use.

 

[EASLOOP]

Thanks for all the input. I shall keep it at 50:1. That is also a big help to me as I also have a 15hp Mariner that runs on 50:1 so I can continue to use the large mariner fuel tank as a top up source for the Suzuki.
Thanks for tip on carb spray. i will do that.
Thanks again folks and good sailing.

 

[jerryat]

>> also allways run the ngine until the carb is empty after use. <<

Totally agree and it's something we always do. Our engine always starts first pull (50:1 ratio as I say in my post above) and runs beautifully. However, the problem EAsloop has may be caused by using the engine on lowish revs for too long each trip. We sometime find that if we're motoring gently for over 10-15 mins at a time, the engine will 'stutter' a bit on opening up the throttle.

Clearly, with the higher oil ratio, the plugs have oiled up a bit, but we find that a good blast of throttle for a couple of minutes is enough to burn it off, and the engine then runs at the higher revs very well indeed.

 

[Lakesailor]

That is born out by the Variable Ratio Oiling systems on the bigger OBs
My Johnson varied from 150:1 at tickover to 50:1 WOT. My little Tohatsu doesn't get much hammer and is mainly below half throttle in the moorings area. There is a known problem of the upper main bearing failing first (lack of oiling, due to gravity effects) on engines that work hard.

 

[lw395]

If in doubt, try a new plug is the golden rule of two strokes!
I generally find NGK plugs better than most.
I agree about 50:1, but I tend to aim for somewhere in between as its not always that precise!, particularly if your not mixing a full can.

 

[andy_wilson]

With modern bearings they are unlikely to suffer any damage from recieving 1/2 strength oil, but the power head and plug is likely to foul / carbon up if run too rich.

If it endures light to moderate load and revs. keep to 100:1.

If it is constantly used heavily at high load or rpm, 50:1 may be advised.

The misfire could be too rich an oil mix, poor breathing due to coke build up, or fouled spark plug - all caused by too much oil. It could be other things as well, uncluding gummed up carb., which could be part related, or also caused by not running it dry before storage, and hence the fuel evapourating leaving the heavier fractions behind.

Carb. cleaner might help.

 

[nyx2k]

i use 100-1 on my 9.9 yamaha when its doing lows revs on the canal and 50-1 when its used at near wot on the sea.

 

[PeteCooper]

I heard a story many many years ago of someone with a 2 stroke scooter. He drove like a man possessed, so to allow for this he added extra oil to the mixture. The engine then seized because effectively it was running on a weaker petrol/air mix which caused overheating.

 

[Kawasaki]

Pete Your dead right.
A few Moons back I was a Vespa and Lambretta dealer amongst other makes.
Repaired quite a few machines that had done just as Your story said.
Also as I have said before, 100/1 is ok with fully synthetic 2 stroke for modern outboards.

 

[pappaecho]

My Suzuki 2.2 manual says run-in at 50:1, then 100:1 except S Africa which is 50:1!!?????????????

 

[Avocet]

My Suzi manual says the same thing - I think they have a lot of alcohol (Ethanol?) in the fuel over there and this breaks down the 2 stroke oil so they use extra to compensate. I'm pretty certain mine also says 50:1 for "commercial" use. I tend to split the difference and give it about 75 to 1!

 

[Kawasaki]

Ethanol will "wash" the engine.
Too much ain't good.

 

[Chris_Robb]

I have a new Tohatsu 3.5 and that says 25:1 running in and 50:1 once run in - I am now confused!

 

[Lakesailor]

Maybe more recent ones are different. Most of the ones people have mentioned are not new.

 

[Scarron]

Of more importance is the quality of the oil;- it'll run best on 100:1 but use a premium fully synthetic oil. - If however you are a cheapskate and use any old cheapo oil, better to stick to 50:1 however expect it to oil up occasionally and have a shorter life.

Paul

 

[Kawasaki]

Trust Me.
Use a full synthetic pre mix oil at 100.
Scarron is right too.