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MacMan
26-01-07, 16:03
Hi all,

I've just brought a new outboard - a Mercury 3.5 Hp two stoke.

Reading the manual gives dire warnings of only using NMMA certified Mercury Tc-W3 2 Cycle oil at 25:1 for the first tank

Now how much of this is marketing and how much will any old oil do the job ?

In particular I am landlocked (Berkshire) and nowhere near a swindelery and wondered if there is something I can pick up at Halfords to do the job ?

Cheers

MacMan

Evadne
26-01-07, 16:09
I think you'll find any old 2-stroke oil will work. I don't know if "marine" 2c oils have anything special in them, tho' I think it would be gilding the lily if they did, but don't use "any old oil", especially if it's old sump oil!

Csail
26-01-07, 16:11
marketing i think. a 2 stroke is a 2 stroke. only my opinion though.

galadriel
26-01-07, 16:15
You might do well to find a shop selling garden machinery, chainsaws etc, they should help. Have a look and see what the spec is on the container.

Kawasaki
26-01-07, 16:19
Have a look at www.rockoil.co.uk (http://www.rockoil.co.uk)
No You don't need "Mercury" oil.
Yes make sure the spec is Tc-W3 2 cycle.
Brand does not matter.
Use the ratios the manual gives You.
Don't be tempted to put "A little more in" once You have run it in, in effect.
Too much oil can also give problems and damage believe it or not.

People might comment that they have used Lawnmower oil, etc and have experienced no probs. Don't be tempted to go down the route of any old 2 stroke oil will do.
Especially as You have a nice new one!
Rock oil, mentioned above are a "Brewer" of oil and produce for lots of well known brand names, so You can buy the same stuff without buying the brand name.
They will be able to tell You who stocks it near to You.
Got no commercial connection, just used their oils for various engines for Years.
Oh and make sure the tin says "Premix" not "injection"

nedmin
26-01-07, 16:20
because they are water cooled they tend to run a bit cooler so they probably have more additives to prevent "whiskering" of the plugs etc. but I cannot see any harm by using any good quality 2-stoke oil. I use 2 stroke motor bike oil and havent had any probs.

Lakesailor
26-01-07, 16:21
Oil for strokes is apparently formulated for running at cooler temperatures than that for air cooled and closed circuit cooling 2 strokes. So I am led to believe.
Can't think it would make a whole load of difference unless you ran it hard before warmed up.

Mirelle
26-01-07, 16:23
Unfortunately outboards are almost the only water cooled two strokes, so you may need to visit a swindlery!

Evadne
26-01-07, 16:24
Good point, I used to use the cheapest oil on my old 2-stroke bike (KH250) because the oil pump would throw so much oil into the mix that the expensive stuff (i.e. Rock oil) was a waste. It all dripped out through the exhaust, unburnt, anyway. With a new engine and a thinner mix, good oil is not such a bad idea.

Kawasaki
26-01-07, 17:10
That was cos the oil pump setting was incorrect!
The KH range was touchy ref carb/oil pump cable settings.
Uknowledgeable dealers of the day would uncrate a machine stick fuel and oil in and whisk em out the door.
If it fired up and went round the block without stalling. That was a Pre Delivery Inspection over.
Must have "tuned" dozens of the buggers back then.
Wrong settings, even wrong plugs.
Peeps who thought the bikes would go better with"softer" plugs.
Cos they were oiling up they'd stick the wrong grade in and have nice holes in the pistons instead!
Twas good fun!

Evadne
26-01-07, 17:14
/forums/images/graemlins/smile.gif Oh well, it's too late now. What I remember well was steaming off down the A3 trailing a haze of blue smoke, Volvo drivers coughiong and spluttering in in my wake. /forums/images/graemlins/smile.gif

Lakesailor
26-01-07, 17:19
Job well done!

macd
26-01-07, 17:23
"Unfortunately outboards are almost the only water cooled two strokes"

Where have you been for the past 20-odd years?

Kawasaki
26-01-07, 17:26
Volvo gets it's own back.
My Geen Un leaves most of the Marina coughing and spluttering in My wake! /forums/images/graemlins/grin.gif

TrueBlue
26-01-07, 18:06
I took the perceived wisdom of cooler running watercooled two strokes seriously and to date have only used Quicksilver stuff from a swindlery.

However, FWIW my local car accessory shop (not Halfords) stocked three grades of Comma oil, mineral,semi-synthetic, and fully synthetic. This last one may indeed be suitable for outboards. The packaging is silent on the subject. One litre was about 7 and 4 litres of the real McCoy was 16. So no real contest.

Even though you're landlocked what about the Inland Waterways, Midland Chandlers at Braunston, chandleries on rivers in your area?

VicS
26-01-07, 19:35
[ QUOTE ]
Oil for strokes is apparently formulated for running at cooler temperatures than that for air cooled and closed circuit cooling 2 strokes. So I am led to believe.

[/ QUOTE ] many years ago I did look at water cooled outboard oil and air cooled motor cyle oil in the lab. I cannot remember any figures now or the brands, but i found that the oil for the air cooled engines had a significantly higher viscosity. I belive not only does the have some direct bearing on the lubrication but will also may affect the fuel air ratios.

If it says an oil to a TC-W spec then that is what should be used

Kawasaki
26-01-07, 20:31
Your right again Vic, it will affect the the fuel air ratio. Which is important.
Ok Guys. Yes use any old oil. The motor Will run, presumably OK.
Long term however probs Will arrive.
Do You want--whiskering plugs, rings gumming up and sticking to the piston ?
Unreliable starting, smoke, noise ,smell. Lack of power etc etc.
Damage to the cylinder, I could go on.
For the amount of usage a little outboard gets the oil price is a none starter really.
Think about this. One small 2 stroke water cooled engine. Used in relatively small bursts. Different usage to Your Lawnmower, Moped, Motorcycle, Chain Saw,Leaf Blower,de dah de dah de dah.
Dormant for long periods, then is woken up and expected to perform.
The little buggers have a hard life in this respect.
So Manufacturers/Blenders do take note of this phenonemon, believe Me I've worked with them.
Could go on and on about this subject but will become boring and serious.
That will not do! /forums/images/graemlins/smile.gif
So stick the correct stuff in it Does make a difference. /forums/images/graemlins/wink.gif

silvertop
26-01-07, 21:19
I have a 3.5 Merc on my tender and use Halfords 2 Stroke oil, never had any problems.

VicMallows
26-01-07, 21:24
Please can you (or VicS) explain WHY type of oil (or indeed the petrol/oil ratio) has an effect on the fuel-air ratio?

Reason I ask is currently investigating a 2-stroke genny with starting difficulties and everything points to carbureter (and in particular slow running mixture jet has negligible effect). Previous fuel mix unknown, though have topped-up with new petrol/air-cooled 2T oil. (OK, should have drained all the old stuff out first!)

Vic (M)

Kawasaki
26-01-07, 23:03
If the mix is too oily or not oily enough.
This applies to premix two strokes only by the way.
The "balance" of air, oil ,fuel is upset.
Sorry triying to explain with My limited typing skills and "on air" vocabullary is difficult.
Especially after a wine or two!
I drink the stuff and She wines at Me!
Tiss a mixture thing again!
Starting prob.
The critical dose of oil won't initially create a starting prob.
"The slow running jet has negligable effect".
Don't know what genny You have. However, "slow running jet" Do you mean the srew You adjust to affect the tickover or the "pilot air srew" which usually affects the mixture up to about a quarter throttle?
If the eng has starting probs the settings for said pilot jet in most cases are--- Screw it in till it is "home" then unscrew for a turn and a half.
Thats the pilot jet sorted for now.
The tickover screw is normally adjusted by screwing "in" to increase tickover speed and screwing "out"to decrease.
What happens if too much oil is added to a pre mix two stroke is as follows.
There are 3 elements to consider.
Petrol air and oil. No air no explosion, no fuel no explosion, no lube no lubrication no go eng seizes.
Cos the 3 have to be in a balanced quantity too much of one will upset tother.
The basic Carb normally sorts this out.
Shove too much oil in and yer basic carb can't cope. What the carb does is"atomise" the correct fuel air oil mix into the combustion chamber by way of help from the piston and ports.
The correct air fuel is needed to make the bang. If too much oil is present it can weeken the fuel air mix. If the mix is too lean, combustion is parred and so is lube.
I could go on and on but believe Me it get's boring.
If You've got starting and slow running probs with a liitle 2 stroke be it a genny or whatever. Sometimes it points to a duff crancase seal on the timing side. Specially if the slow running adjustement seems to have no affect.
What happens is there is a loss of crancase pressure and no amount of fiddling with slow running settings will cure this. Air is sucked in through the duff seal and she won't idle or start too easily. Any amount of slow running jet adjustement is futile.
Has the eng stood for some time?
Always go back to basics.
Take the plug out. Check the spark.
Drain the carb/float bowl.
Check the tank can breathe.
If she don't fire after three pulls summats up!
Choke setting/throttle setting/fuel on etc etc.
Old fuel, especially with pre mix two strokes isn't nornmally the prob ref starting.
Consider this. A premix 2 stroke doesn't receive "pure petrol" it's by nature already contaminated by oil.
So they are not fussy high tuned gadgets that need 100% high octane supuer juice.
Especially at our level of outboards and gennys etc.
Clean fuel and oil Yes but not F1 technology. Water is a nuisance we don't want that in the float bowl.
So we need a good spark, at the right time some clean fuel(with a bit of oil in) some air to ignight and ther You go simps innit.
Type of oil has little affect on air oil ratio or petrol oil ratio. Amount does.
Soory not to be more clear but it is 23.00 hours!

VicMallows
27-01-07, 12:59
Kawasaki,

Well it gave you some late-night typing practice /forums/images/graemlins/grin.gif

I am fairly familiar with small 2 and 4 strokes .....it was just the specific comment concerning the oil altering the fuel/air ratio (to any significant degree) that I was querying-in case I was missing something obscure. Was talking about a difference of perhaps 25:1 rather than 50:1 (old 60s lawnmower used 16:1 .... and you bought it from a pump which mixed anything from 8:1 upwards /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif )

Anyway, seems in this case old fuel WAS the culprit. Also realised (as usual in the middle of the night ... didn't have any wine last night, only beer) that the reason the slow running mixture screw did not appear to have effect was because it's a governed engine, and NEVER normally runs slowly /forums/images/graemlins/frown.gif . Once slowed manually, the mixture screw works as I would expect.


Vic

27-01-07, 19:36
Marine 2 stroke is different from normal Halfords / Off shelf garage stuff. BUT I have used whatever 2 St oil I can get at time ... as most Petrol Stations have it on shelf. If you buy near marina / harbour - often the Petrol St. will have marine stuff as well as normal 2T ... further away only normal 2T ...

Problem for you - if anything goes wrong with it under warranty and the find "other" fuel in it ... ?? Warranty ??
All my O/boards are well past warranty days ... and I use any 2T I can get.

Now experts will shoot me down >....

VicS
28-01-07, 00:17
[ QUOTE ]
Now experts will shoot me down >....

[/ QUOTE ] I'm certainly not claiming to be an expert but I suggest that using a (slightly heavier) aircooled engine oil instead of using A TC-W spec oil in a water cooled engine will be less of a problem from the lubrication point of view than doing the opposite ie using a TC-W oil in an air cooled engine.

Quite how much effect it will have on the air fuel mix I am not so sure, despite the fact that I raised that point earlier, especially at the low percentage of oil used in modern outboards The logic is though that a more viscous oil in the mix will make the fuel more viscous and lead to a somewhat leaner mixture being produced by the carb. If both the high and low speed mixtures can be adjusted then adjustment of those will probably suffice. I forget now how much difference in viscosity I found between the two types of oil.

It is interesting to note that the instuction books for my Seagull outboards (1973 and 1974) just recommend a range of ordinary 2 stroke oils (Did the TC-W specs exist then ?) or if not available a non-detergent SAE 30 oil. I used a SAE 30 oil for a while because I had access to a supply. With a 10:1 mix did it smoke!

28-01-07, 12:32
[ QUOTE ]
[ QUOTE ]
Now experts will shoot me down >....

[/ QUOTE ] I'm certainly not claiming to be an expert but I suggest that using a (slightly heavier) aircooled engine oil instead of using A TC-W spec oil in a water cooled engine will be less of a problem from the lubrication point of view than doing the opposite ie using a TC-W oil in an air cooled engine.

Quite how much effect it will have on the air fuel mix I am not so sure, despite the fact that I raised that point earlier, especially at the low percentage of oil used in modern outboards The logic is though that a more viscous oil in the mix will make the fuel more viscous and lead to a somewhat leaner mixture being produced by the carb. If both the high and low speed mixtures can be adjusted then adjustment of those will probably suffice. I forget now how much difference in viscosity I found between the two types of oil.

It is interesting to note that the instuction books for my Seagull outboards (1973 and 1974) just recommend a range of ordinary 2 stroke oils (Did the TC-W specs exist then ?) or if not available a non-detergent SAE 30 oil. I used a SAE 30 oil for a while because I had access to a supply. With a 10:1 mix did it smoke!

[/ QUOTE ]

Funny thing is my Genny instructions specifically say do not use Marine Based 2T ..... so the air-cooled bit must have credence.

I may throw some OMC 2T and normal 2T at my lab - see what they come up with ... but won't be for a while - we are in move at moment and loads of work going through ...

jimbaerselman
28-01-07, 18:56
[ QUOTE ]
I have a 3.5 Merc on my tender and use Halfords 2 Stroke oil, never had any problems.

[/ QUOTE ] Yet.

Always buy any oil on specification - be it for a diesel engine, a petrol engine, or a water cooled two stroke or an air cooled 2 stroke. Brand is immaterial, though brandowners try to hide that fact.

The spec is usually hidden as an API number in small print (American Petroleum Institution - I think). Their web site produces wonderful lists of which specs supersede which others, and which are suitable equivalents . . .

andy_wilson
29-01-07, 10:17
Halfords sell oil for high temperature air cooled 2 stroke engines that 16 year olds buzz around on, as will the lawnmower / strimmer / chainsaw shop.

The good news is TCW-III is great for outboards, and Quicksilver (the stuff mercury / Mariner bring to market) is almost as good as OMC (Johnson / Evinrude).

It is designed for outboards which are over cooled, and is very low ash to prolong plug life, particularly if used at low speeds (by plug life I mean the duration between when clean-ups are required).

Use any old **** for the first concentrated tank full may lead to starting problems due to plug fouling, and unnecisarily coat the power head with excessive deposits.

If you got this far on the web, you could have a litre delivered to you tomorrow from one of the big mail order chandlers, ask the engine supplier to help, or have a drive to your local dealer:

http://www.walkeroutboards.co.uk/