Fuel Mix - Mariner 5HP

Re: Fuel Mix -Measuring??

Ian maybe I am wrong but I think you meant to say 10cc oil in 1 Litre of petrol makes100/1.


I think you should put 50cc into 5litres to make 100/1
 
Re: Fuel Mix -Measuring??

Yes I'm wrong.

10cc for one litre makes 100:1 as you say so. 200cc for 50:1 in a litre of petrol . Just used to looking at the graduations on the oil bottle.
 
Re: Fuel Mix -Measuring??

1 litre = 1000 cc

so at 100/1 = 1000 / 100 = 10cc to 1 litre

so you are correct - he's wrong ....

now I used to have real trouble .... had a seagull at 15/1 and a Mariner at 100/1 ...... the number of times i forgot which can was which !! So I stopped adding till I needed it .... that failed the practical test as well !!!! So back to mix and store. The seagull has since been sold off !!

Nigel ...
Bilge Keelers get up further ! I only came - cos they said there was FREE Guinness !
 
Bit of a thread revival but it would be convenient for me to run my Mariner 5hp 2T on 50:1 which is required for all the other 2T engines in my life.

I've used 100:1 to date for fear of plug oiling and poor starting, but I've never seen evidence of either on this engine so perhaps I'm over thinking it.

FWIW I had the engine apart this winter and there was plenty of oil around the crank/crank case etc.

Manual says use 100:1 for leisure, 50:1 commercial.

I think I can guess the response but does anyone think I'd regret running 50:1 henceforth?
 
Mark-1 said:
I think I can guess the response but does anyone think I'd regret running 50:1 henceforth?
Click to expand...

Don't think so.
I've been using Aspen 2 stroke fuel (50:1 mixture) on my outboard (Mariner 2.5) for over 20 years.
I prefer the Aspen to a DIY mixture. The main reason being that the fuel never seems to go 'off' even when I haven't used the outboard for a couple of months. Never, ever have I had a clogged fuel line.

Aspen 2 | Aspen 4 | Premixed Petrol | Aspen Fuel
 
Koeketiene said:
Don't think so.
I've been using Aspen 2 stroke fuel (50:1 mixture) on my outboard (Mariner 2.5) for over 20 years.
I prefer the Aspen to a DIY mixture. The main reason being that the fuel never seems to go 'off' even when I haven't used the outboard for a couple of months. Never, ever have I had a clogged fuel line.

Aspen 2 | Aspen 4 | Premixed Petrol | Aspen Fuel
Click to expand...

So that's a vote for 50:1. Love the idea of Aspen, but (touch wood) I've yet to suffer from any fueling problems with my collection of infrequently used small engines so I can't currently justify the cost. (That could change!)
 
I use a measuring bottle with the oil added to bring it up to the mark. I have always been happier with a mix nearer 33 to 1. The plugs don't oil up at that and no more appreciable smoke.
 
Mark-1 said:
Bit of a thread revival but it would be convenient for me to run my Mariner 5hp 2T on 50:1 which is required for all the other 2T engines in my life.

I've used 100:1 to date for fear of plug oiling and poor starting, but I've never seen evidence of either on this engine so perhaps I'm over thinking it.

FWIW I had the engine apart this winter and there was plenty of oil around the crank/crank case etc.

Manual says use 100:1 for leisure, 50:1 commercial.

I think I can guess the response but does anyone think I'd regret running 50:1 henceforth?
Click to expand...
I've never had problems with 50:1 in various outboards spec'd at 100:1.
I always use NGK plugs.
I don't do a lot of idling or slow running.
I'm moderately careful about turning off the fuel tap a few tens of metres short of the slipway.
I use decent oil.

When I had a big premix engine, a 40HP twin, I was more careful, as it spent more time running at low speed.

I tend to run the strimmer at 33:1 though, those engines are very crude inside.
 
TernVI said:
I use decent oil.
Click to expand...

Wise. Currently I'm not - I use Oregon Semi-Synth Chainsaw oil because I accidently bought several bottles instead of one on Amazon. Based on zero evidence I suspect that is not optimized for marine use and a significant part of its design brief is not damaging forests. As soon as that runs out I'll be switching to first class quality oil.
 
Mark-1 said:
Bit of a thread revival but it would be convenient for me to run my Mariner 5hp 2T on 50:1 which is required for all the other 2T engines in my life.

I've used 100:1 to date for fear of plug oiling and poor starting, but I've never seen evidence of either on this engine so perhaps I'm over thinking it.

FWIW I had the engine apart this winter and there was plenty of oil around the crank/crank case etc.

Manual says use 100:1 for leisure, 50:1 commercial.

I think I can guess the response but does anyone think I'd regret running 50:1 henceforth?
Click to expand...
50 :1 will be suitable and would be preferred to 100:1 by many owners.

Use a TCW-3 certified 2 stroke outboard oil. Quicksilver is a brand widely available.
Garden machinery engines are air cooled and run much hotter than a water cooled outboard engine. The oil is consequently a higher viscosity grade.

Spark plugs have been mentioned . . . . . . Use the plug type , and gap, recommended in your user manual. . . . . NGK BPR7HS-10, I think ,which are supplied ready gapped at 1.0mm
 
VicS said:
50 :1 will be suitable and would be preferred to 100:1 by many owners.

Use a TCW-3 certified 2 stroke outboard oil. Quicksilver is a brand widely available.
Garden machinery engines are air cooled and run much hotter than a water cooled outboard engine. The oil is consequently a higher viscosity grade.
Click to expand...

Many thanks, I didn't know that, I'll make the switch.

VicS said:
Spark plugs have been mentioned . . . . . . Use the plug type , and gap, recommended in your user manual. . . . . NGK BPR7HS-10, I think ,which are supplied ready gapped at 1.0mm
Click to expand...

Yeah, I use the right plug, carry spares and change them frequently. (Years of cleaning up plugs in my youth made me finally realize it's just not worth it - £5 every couple of months gives a start on the first pull for zero effort. Wire brush, less so.)
 
RichardS said:
Your engine will basically run on any oil at 50:1. In the good old days we just chucked whatever we had to hand into our premix tanks. The oil viscosity doesn't matter because any viscosity divided by 50 is the viscosity of petrol. (y)

Richard
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Well no, because the oil ultimately ends up (more or less) neat in the crankcase keeping it all nicely lubed.

(But I agree with your main point - it will run on anything, including used engine oil I've drained out of my car sump. I also suspect that oil is so good now 100:1 today is as good as 50:1 was 40 years ago - I just feel like giving it the best chance possible.)
 
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Regarding 50:1 starting, my 4 HP Mercury requires several pulls (like 7) to start after, say 1 month of not being used (I always run carb empty by disconnecting fuel line first). After few minutes of running, it starts on the first pull. Could many pulls to start be related to the mixture?

PS. From my non-expert understanding, using any oil might make the plug dirty as it could be less combustive.
 
Mark-1 said:
Well no, because the oil ultimately ends up (more or less) neat in the crankcase keeping it all nicely lubed.

(But I agree it will run on anything, including engine oil I've drained out of my car sump. I just feel like giving it the best chance possible.)
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The engine components are continually being washed down by the petrol / oil mixture when the engine is running. Any engine oil is going to be within the same general range. Modern two stroke oils are thin so, unless you can find some very specialised 0W-0 oil, anything is going to be equal or better in viscosity terms. :)

Richard
 
I've been advised by marine engineers to use a mix of 50:1 even if the manual says 100:1. There reasoning is that most two stroke engines are now quite elderly and the 50:1 ratio increases lubrication and hence engine wear.
 
RichardS said:
The engine components are continually being washed down by the petrol / oil mixture when the engine is running. Any engine oil is going to be within the same general range. Modern two stroke oils are thin so, unless you can find some very specialised 0W-0 oil, anything is going to be equal or better in viscosity terms. :)

Richard
Click to expand...

Last time I split the crank of a 2T engine (this winter) to change the main bearings there's was plenty of lovely lubricating oil about left behind to do its job. There was no petrol.

From that I conclude petrol vaporises out of the crank leaving oil behind on the crank/bearings etc, which is desirable. That's not to say that mixture provides no lubrication. There must also be some 'washing' otherwise the crank would fill with oil over time.

So there is neat oil in the crankcase and that all explains why the top bearings tend to go first - the neat oil runs to the bottom when the engine is off.
 
One weekend, I filled up the outboard from the can and puttered out to the boat and back - maybe 10 minutes each way. The motor didn't sound quite like normal, but gave no problem. When I got home, neighbour popped around and said 'I borrowed your can to put in my car as it was in the red but when I got to the garage, I refilled it, hope that's OK?' 'Did you put any two stroke oil in?' ' No'
 
Mark-1 said:
Last time I split the crank of a 2T engine (this winter) to change the main bearings there's was plenty of lovely lubricating oil about left behind to do its job. There was no petrol.

From that I conclude petrol vaporises out of the crank leaving oil behind on the crank/bearings etc, which is desirable. That's not to say that mixture provides no lubrication. There must also be some 'washing' otherwise the crank would fill with oil over time.

So there is neat oil in the crankcase and that all explains why the top bearings tend to go first - the neat oil runs to the bottom when the engine is off.
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I don't disagree ..... but, as I said, almost any engine oil you use is going to be thicker than a modern two stroke oil so if viscosity were a prime consideration in the context of coating the internals then engine oil is probably going to be the better bet.

Richard
 
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