Boat 2 stroke mixture

[joostan]

I was just wondering if anyone can help me with a little problem I have.

Can anyone let me know what the correct mixture ratio should be for a 1984 Johnsons Envinrude 35hp 2 stroke 2 cylinder engine as the person I bought it the person gave me a rough idea but not a ratio.

[mark]

50:1

[joostan]

Thanks Mark, I was told different so might explain the spluttering after a time and the ocasional cutout.
We checked the fuel flow, carb, fuel filter and they were all fine. Mixture was the the next thing to check.

[PaulGH]

Yup as mentioned 50:1 mix for Johnsons
(to save the maths it's 20ml oil to 1litre petrol, I only say that because I know someone who was mixing 50ml oil to 1litre petrol thinking 50 to 1 was 50ml lol).

[steve.]

Get a mixing jug from the boat shop. It will show you how much oil to add the the amount of petrol youve put in your tank. Should only cost a couple of quid.

[Alfie]

Same question for 48hp Mariner. Have been using 100-1, is that correct?

[PaulGH]

Same question for 48hp Mariner. Have been using 100-1, is that correct?

I think you're going a bit tight on the oil mate, most engines these days are 50 to 1 mix.
A quick search on Mariner 50hp oil mix on google suggests 50:1 aswell.

As a side note don't use cheap supermarket 2 stroke oil always use propa marine 2 stroke (any TCW3, brand names are irrelevant). I'm probably preaching to the converted but.....

[joostan]

.... As a side note don't use cheap supermarket 2 stroke oil always use propa marine 2 stroke (any TCW3, brand names are irrelevant). I'm probably preaching to the converted but.....

I understand that there is a difference with the marine 2 stroke oil but can someone please let me know what that is?

[mark]

I understand that there is a difference with the marine 2 stroke oil but can someone please let me know what that is?

TCW3 is the stuff. Normal 2 strokes are designed for bikes, lawn mowers etc, which have very hot exhausts so any unburnt oil will get burnt in the exhaust

outboard motors have a cold exhaust due to being in the water and having cold water running up the inside of them so normal 2 stroke oil will build up in the exhaust, cause it to gum up

TCW3 is designed to burn at much much lower temperatures so any unburnt oil doesn't stick in the exhaust

Last 2 stroke premix I had, I used a glass jar. think it had pesto sauce in it originally, 100ml.

so 1 jar full of oil was 100ml which would get thrown in one 5 litre can of petrol or 5 jars in one 25 litre fuel tank, made premixing a doddle

[joostan]

Thanks Mark

[King Ling]

Same question for 48hp Mariner. Have been using 100-1, is that correct?

100/1 is correct for mariner/yamaha 50/1 for johnson/evinrude

[christighe]

Just read your query on 2 stroke mix and found an old manual for johnson/evinrudes. Engines upto 1974 used a mix ratio of 24/1, the recommended ratio for yours is 32/1 but with modern 2 stroke oil you could get away with 50/1. Personally if I was you though I would use 32/1, it may smoke a bit more but you can be sure it is getting the right lubrication and it will keep the temperature down. Try running at 32/1 and then 50/1 to see if it makes much difference.

[joostan]

Just read your query on 2 stroke mix and found an old manual for johnson/evinrudes. Engines upto 1974 used a mix ratio of 24/1, the recommended ratio for yours is 32/1 but with modern 2 stroke oil you could get away with 50/1. Personally if I was you though I would use 32/1, it may smoke a bit more but you can be sure it is getting the right lubrication and it will keep the temperature down. Try running at 32/1 and then 50/1 to see if it makes much difference.

Thanks mate [note to self to get a manual]

...TCW3 is designed to burn at much much lower temperatures so any unburnt oil doesn't stick in the exhaust

So I used normal 2 stroke last time out cause I was ill advised, would that then possible cause the engine to run fine for about 45 mins then start to cough, splutter and eventually cut out but will start again with no problem??