25:1 Fuel Mix?

[skipper20]

Hello, new guy here. I recently purchased a Silver engine #WSL 617JJ6. so from this engine identifier it was made in Sep., 1976. As such, It's rated for a 10:1 fuel mix. The seller, an independent outboard repair shop specializing in all brands, seemed to know a bit about Seagulls. He said it had not been converted to use a 25:1 mix but claimed that with today's improved 2 stroke outboard oils, it's no problem using 25:1. Is this true? If there's any doubt, I'll just dump the existing fuel from the tank and fill with a 10:1 mix. I don't really have the skills to disassemble the carb to confirm that it has a 25:1 jet (the seller insisted it didn't) so it seems easier to go back to 10:1 if there's a concensus among you Seagull specialists that 25:1 won't do the job. In my case, "job" means pushing a 500 lb. wood sailboat, when the wind dies down, sometimes in tidal currents as high as 6 knots. So, your comments will be sincerely appreciated. TIA,

Bill in Seattle

[Silver Surfer]

We had a little thread about this very subject fairly recently, and the general consensus seemed to be "Why take the chance?" It was designed to run on 10-1, so to run it on 25-1 without any modifications seems a bit risky. (to me) 'Outsiders' don't take into account the old school design, and the fact that the more oil on the bearing surfaces, the better. There are Seagulls out there that are getting close to the end of their life, but the oil being present in copious amounts keeps them chugging along. I have the opportunity to change one of my Seagulls to run on 25-1, but it isn't broke, so I have no intention of 'fixing' it.

[Keith.P]

The previous post is correct, you can change the jet on some later motors and use a 25:1 fuel mix, as seagull do sell the conversion jet.
Most of us on this site don't have seagulls that will run on 25:1 or are even able to be converted to use 25:1, plus we all would like them to last.
The motor has an Amal carb, Undo the banjo and you will see the two jets inside, One may look newer that the other, that's if you need to know what jet it is.
They are made to run at 10:1 so that's what I do, plus I'm not a tree hugger.

[headdownarseup]

Here's a simpler answer.

Anything made before 1978 should already be running on 10:1. In an ideal world, keep it that way.
There are plenty of accounts around that some of these older pre 78 engines have been successfully converted to run at 25:1 but you must first remember that at 25:1 there's a lot LESS oil in the fuel mix, something that older seagulls don't really like too much. Secondly with less oil in the mix there is potential to accelerate any wear on the more sensitive bits inside your engine. The rule of thumb here is to stick with 10:1 and forget about the fact they leave behind a smoky fog. It's normal and they all do it. Having more oil in the mix (10:1) has probably kept your dear old gull's engine going all these years fairly trouble free.

Anything made after 1978 wil have been FACTORY CONVERTED already, along with the small design change to the crank bushes which safely allows this lower oil content.

If smoke levels trouble you, (and let's face, these old gull engines do have a nasty smoking habit at times) try changing the brand of 2 stroke oil for something more modern, but for the sake of your gulls engine don't reduce the amount of oil in the mix without first seeking further advice from one of us.

This is a sensitive subject to me, and something i tried quite hard to explain on a previous posting.


Jon

[Collector Inspector]

I will concur with the above most +++++++

While a possible smoky 10:1 can be a bit challenging around other uninformed boaters on the water, it is something to adhere to if ya have that style of motor. Gull or not.

Some 10:1 motors do not smoke when operational temps have been achieved aye?

Some of us run lower oil based on experience and a keen ear and what an individual engine actually LIKES!

Mostly not that much of a difference to actually crow about. Slightly less smoke and leave the oil mess just acceptable but always present.

Experience level 101 starts at say 30 years using old engines on a transom and being able to be at one with each Old Dear at the time of HAVING SO MUCH FUN!.

Stay safe with what is recommended and your engine will live on probably longer than you (Routine maintenance and respect of course)

Enjoy.

BnC