Engine query

MartinL86 · 28 October 2016, 05:43

Hi guys, just bought my first SIB an exel 365 with a mariner 15hp 2 stroke, I'm seeing alot of different opinions on correct fuel mix ratios, the guy I bought it off used 30:1 but this was only on freshwater, not sure if that changes with saltwater use, should I keep the same?

JimRib · 28 October 2016, 08:10

More info on the engine would be good, a picture of the info plate found on the saddle would be good or of the engine, as someone will be able to tell what it is. usually they are 50:1 saltwater or freshwater makes no difference to the oil mix

Fenlander · 28 October 2016, 08:17

Yep need more info but 30:1 is very likely far too much oil which will smoke and possibly give less than clean running.

50:1 as jimrib says is a failsafe mixture but some models were 100:1... as were the last 3 Mariner/Mercury 10/15hp 2-stroke OBs I've owned. In the manual they said for commercial operation use 50:1 for the 100:1 models so I ran a happy medium of 75:1.

uncle al · 28 October 2016, 13:45

I always used to advise customers 50/1

beerbelly · 28 October 2016, 17:42

my old mercury 15 2005 year ran much better on 50-1 , that's what was recommended

MartinL86 · 28 October 2016, 19:20

Cheers guys much appreciated! Looking to do the maiden voyage next weekend, can't wait!

jeffstevens763@g · 28 October 2016, 20:04

Never heard of 30-1 50-1&100-1 yep

beamishken · 28 October 2016, 22:18

Old seagulls were very rich 25-1 I think

Bucksribster · 28 October 2016, 22:59

Very old seagulls were 10:1. Really!

Limecc · 29 October 2016, 01:19

Higher the oil amount then the leaner the engine runs I understand because excess oil takes the place of fuel. I doubt this would cause any damage on a cool running marine engine but could be a problem on an air cooled motorcycle.

I wish the OP well on his maiden voyage, still little likelihood of trying mine yet because of a self build project. Very frustrating!

Wife has me scared now because of possible mouse damage over winter. The boat is still in it's cardboard box on the garage floor. How is it best stored to mitigate such an attack?

MartinL86 · 29 October 2016, 06:37

Well I'd looked into it and seen common ratios son was shocked when he said that, will go with 50:1!

beerbelly · 29 October 2016, 06:49

Quote:

Originally Posted by Limecc

Higher the oil amount then the leaner the engine runs I understand because excess oil takes the place of fuel. I doubt this would cause any damage on a cool running marine engine but could be a problem on an air cooled motorcycle.

I wish the OP well on his maiden voyage, still little likelihood of trying mine yet because of a self build project. Very frustrating!

Wife has me scared now because of possible mouse damage over winter. The boat is still in it's cardboard box on the garage floor. How is it best stored to mitigate such an attack?

store it in the house to keep away the mouse . hey I'm a poet and I didn't even know it

MartinL86 · 29 October 2016, 07:29

Hahaha that made me laugh! Surround with 150 baited mouse traps, watch your toes in the night!

Fenlander · 29 October 2016, 12:04

Get a cat! I don't like cats that much but daughter got one 7yrs ago and our garage went from mice infested to totally clear.

jeffstevens763@g · 29 October 2016, 13:45

Would the seagul 25-1 be before modern two stroke oils or was it because they were air cooled?

beamishken · 29 October 2016, 16:42

There's quite a few older 2 stroke engines run 25:1 stihl saws chainsaws etc some motocross bikes are 33:1 even with water cooling so don't think it's to do with aircooling just the level of protection required