Smokey old outboard

[IanPoole2]

I have managed to get an old 2 stroke outboard going after it had been left standing for over 2 years. 2HP Mariner. Whilst it runs I'm getting loads of white exhaust fumes, is this too much oil in the mix, I thought that was blackish smoke, not enough oil, I thought that was blueish smoke and a run away engine, or some other problem? It seems to run fine, I ran it for over 30mins in fresh water.

<hr width=100% size=1>

 

[WayneS]

That will be your 2-stroke oil burning. Suggest you check your mix. Most of these engines should run on a 50:1 or 100:1 mix but check with a dealer.

On my engine I take the lack of white smoke to mean that I forgot to add oil..... Fact of life unfortunatly.

Cheers

Wayne

<hr width=100% size=1>

 

[IanPoole2]

Thanks Wayne,

Looks like I've over cooked the oil.

Whats the best colour for the smoke then?

Ian

<hr width=100% size=1>

 

[WayneS]

You are always going to get some white smoke, cos that's 2-strokes for you. It's just the quantity of smoke.... A big smoke cloud could be too much oil in the mix, no smoke means not enough.

Usually you should be able to see a small amount hanging around the engine while motoring (with engine at operating temp, when cold you will get more).

However, do not adjust your mix according to the amount of smoke as that is very subjective. Find out what the correct mix should be and stick to it (Even if that means it is very smokey)

Also, make sure that you use Outboard 2-stroke oil, not motor-cycle. There is a good reason for this but I don't know what it is.

Cheers

Wayne


<hr width=100% size=1>

 

[tcm]

Re: and

agree with wayne. Good thing bout 2strokes is there ain't a lot to adjust. No valves anyway. I bet the ratio of oil to fuel should be between 50 -1 to around 100 to 1. You will get a good idea of how it's going by looking at the spark plug (hint -always have a spare spark plug and if any probs, puta new one in as first resort). After some running, the spark plug should ideally be the colour of a rich tea biscuit. A bit oilier will not do significant damage, but any lighter and there's not enough oil which is obviously very bad. I also bet that the gap on your spark plug is too big, hence not a fat enuf spark, hence unburnt fuel (white) instead of half burnt oil (blue) but I'm not an expert.

<hr width=100% size=1>

 

[jhr]

I put 50-1 in my old 2hp Mariner - can't remember who told me those proportions but I think it was a Mariner dealer - and it runs fine, tho' there'll always be a bit of smoke, as other say.

<hr width=100% size=1>

 

[martinb]

Unburned fuel would show up as black smoke, excessive oil would show as blue smoke and water would lead to white smoke, however blue can look white.

First thing to do is throw away the fuel and mix some more with the correct ratio. Excessive oil will not only lead to oiling up of the engine and excessive smoke but will lower the octane rating of the fuel and could lead to detonation under load. Insufficient oil will cure your smoking problem for good - not to be advised!

Martin

<hr width=100% size=1>

 

[yoda]

If you haven't already then drain the tank and fuel line, clean through with new fuel and also clean out the bowl on the carb as water and sediment tend to collect there. 50:1 is the right ratio for the fuel mix.

Yoda

<hr width=100% size=1>

 

[oldharry]

Excesive smoke from a 2 stroke can often be a symptom of worn and leaking crankcase seals - never quite worked out why - and new seals are not always easy to fit. Additional symptoms will be poor starting, irregular idling, and stalling at low speed. Trouble is, these symptoms can be due to carburation, oil mix, use of wrong oil, and other mechanical problems (worn bearings, piston faults, reed valve or ring troubles etc) too! So not too easy to diagnose, and not something to make a 'snap' diagnosis over - you can end up spending lots of time and money fixing the wrong bit, only to find the original symptom is still there!

Twin cylinder outboards are often prone to oiling and faults on the lower cylinder only - particularly if they have been left, as the crank centre seal fails allowing all the oil to drop into the lower half!

'Orrible things 2 strokes once they start misbehaving..... as anyone who has worked on the old Stuart Turner inboards will tell you.

<hr width=100% size=1>