Upset century

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red42hj
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Re: Upset century

Postby red42hj » Fri Sep 01, 2017 8:56 am

Thanks for all your reply gents; no the piston ring grooves were not coked up.
Its all assembled and ready to go, just waiting for a new spring for the points to arrive.( I damaged the last one on removal).
I read somewhere that 2 cv points could be adapted. I that true?
Red.

headdownarseup
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Re: Upset century

Postby headdownarseup » Fri Sep 01, 2017 8:20 pm

Going back slightly here to an earlier question, with most of these seagulls they generally respond quite well to a good deep cleaning especially if they've been sat for several years in a shed or garage. That is to say whip its head off and clean the passage ways within, clean the gearboxes out of messy gloop, clean and regap the points etc. etc. Most of the time this is pretty much all they need unless there's something more terminally wrong with them.
Corrosion will take its toll on most parts made from steel or iron. Aluminium parts will dissolve a little bit slower. Treat and protect both as you see fit.

As for the internal parts being worn out to the extent they are no longer serviceable, well to my mind 9 times out of 10 it's unlikely as there's usually more than enough oil in the fuel mixture to keep all the moving parts well lubricated. For most of the earlier engines a 10:1 fuel mix has plenty of oil in it to keep everything almost saturated with oil, so maybe a heavily worn cylinder might never happen. Piston rings can wear though if the proper fuel mix isn't followed. Similar things with the slightly later engines from 78 onwards. 25:1 fuel mix still has plenty of oil in the mix to keep all the moving parts well lubricated, although by this stage in seagull history certain modifications have already taken place to allow for a less smokey fuel mix to be used. Trouble starts when some older (pre 78) engines get converted to a leaner mix. Oil is vital for several reasons with older seagulls as not only does it provide the lubrication but also to some extent maintain an effective seal around the crankshaft bushes. With less oil content in the fuel mix, and plenty of hard running, chances are that bushes start to wear quickly, rings can start to wear out, and probably before that all happens the dear little engine will give you all the warning signs well before that anyway.(poor or difficult starting, loss of power etc. etc.)

Decoking in seagulls isn't usually necessary, all the manuals will tell you the same. BUT, to those folks that do work on these little gems from time to time i wonder how many of you have noticed that some engines have a much heavier layer of carbon deposits around the piston and inside the cylinder head.
To date i've come across a couple of well used gulls that have been really badly coked up on the piston crown and around the ring grooves, not to mention the thick carbonised crud inside the exhaust tube. Is this something to do with modern fuels or is it more to do with the quality of the oil used in the mix? If i were to analyze this further i'd say there's a combination of many things that cause this. Fuel quality will certainly have a lasting effect. Oil quality (not necessarily quantity) in my opinion has a lasting effect, as does the way in which you use your outboard. And then there's the M word. MAINTENANCE. Without a maintenance regime any engine will fall foul to the gremlins now and again.


If you know what you're doing you can alter (slightly) the ignition timing. Adjusting the points gap either bigger or smaller will do this, as will repositioning the baseplate but this is a more difficult proposition and probably best left alone. CDI's are different again and more complex.
Not sure if citroen 2cv ignition springs are interchangeable with seagull ones, but it might be worth a try i suppose. (i've got a box full of old seagull points boxes with springs in them, you should have asked me for one and i would have given you one for free :roll: )

Depending on which carb you have fitted to your century, Amal 46n 2jet carbs don't really have any inbuilt adjustment in them other than changing the jets, unlike the Villiers which you can alter the needle height and to some degree the fuel . Some of the later type Amal carbs are a better choice if its adjustability you're after.
I've mentioned in the past how to "read your spark plug" for some warning signs. Wet and oily doesn't always indicate what you think it might!
Clean carbs and fuel lines etc. is always a good starting point, as is the ignition system. If both of these are in the best shape you can get them, the rest is down to some experimenting with different 2 stroke oils from different manufacturers.
Oil has come a long way in the last 20 or so years, as has the fuel that we burn. (who can remember 2 star and 4 star petrol 8) before unleaded became the norm)
All of my flock (i'm embarrassed to say nearly 30 of the bloody things now :oops: ) are happy with a modern good quality semi synthetic 2 stroke oil, NEVER do i use a cheap and nasty oil like some of the older type mineral oils, but ALWAYS at the correct mixture for whichever engine i'm using. More often than not it'll be an old 102 (and they're not as smokey as you think either, especially at 10:1)The only trouble (if you can call it that) that i get with my seagulls is with fuel leaks, and that's generally from a lack of use as the gaskets and seals dry out :roll: Apart from that they run strongly and reliably all day like that provided you give them some TLC once in a while.

Hope this helps

Jon

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Charles uk
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Re: Upset century

Postby Charles uk » Fri Sep 01, 2017 10:18 pm

Jon have you looked into the lubrication requirements of your plain bearing Seagulls?

These powerheads were designed to run a 30 weight engine oil fuel oil mix with a fairly high viscosity oil, modern semi & fully synthetic 2-stroke lubricants have a lower viscosity as their principal use is for a modern fully jewelled powerhead that has very few, if any plain bearings.

All of the pre 25:1 Seagulls had the same bearing clearances from 1931 up to the 25:1 era, so running a modern oil might not be the best treatment for a Seagull that's getting close to it's pension age!
Make it idiot proof and someone will make a better idiot.

headdownarseup
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Re: Upset century

Postby headdownarseup » Sat Sep 02, 2017 4:17 pm

I agree with what you're saying Chas concerning bearing clearances and so on. (but not entirely)
My faith lies with modern oils these days. Having had a fair bit of hands on experience myself with a lot of different engine types old and new there is some benefit to using modern oils over older mineral types. As always, use caution.

Older mineral type oils are pretty much the minimum that we can expect in terms of lubricating qualities, and being that most seagulls as you say were designed around this methodology it stands to reason that most folks like to stick with what they know. I fully accept that. Not knocking that in any way.
Whichever oil someone is using, it still gets diluted into petrol the same way no matter how thick or thin the oil's viscosity is to begin with. What happens to the oil once it's dropped out of the fuel/air (inside the crankcase) depends on its ability to adhere to moving parts and to deal with greater temperature changes and pressures etc. and this i strongly believe is where modern oils are better than mineral types. All of the oils i use in my gulls EXCEED all of the minimum specifications that a mineral oil would have, e.g. API TC JASO FB API-TD and anything else there might be with other brands of oils ,and in this respect i consider that to be a good thing rather than a bad thing. When all is said and done, TCW 2 , 3 or better is the accepted minimum when it comes to oil specs in a seagull. Right or wrong?

What i was trying to put across with modern 2stroke oils is that they're (in my opinion) a better choice despite being a slightly thinner viscosity (in layman's terms you'd hardly tell the difference quite honestly) generally have far less ash deposits which can lead to a heavy build-up of carbon around some sensitive parts inside an engine, don't produce the levels of smoke that you'd expect with older mineral oils ,and perhaps this is why we've seen a lot of folks wanting to convert older pre 78 engines to 25:1 because they're worried about how much smoke their old seagull is coughing up each time they go out on the water. Forget about anything to do with racing here Charles, a lot of us mere mortals use our seagulls for more mundane purposes that don't involve going flat out all the time. If somebody's engine is badly worn out to begin with ,then none of what i'm saying here is going to make a blind bit of difference either way. My point with modern oils is PRESERVATION rather than CORRECTNESS. But then again i take a lot of my engines apart fairly regularly anyway. Most other folks wouldn't, so how would they see what's going on inside their own engine unless they strip 'em apart once in a while.

Using semi-synthetic oil hasn't done any of my flock any harm at all. Quite the opposite in fact. It's actually kept them in very good overall condition all things considered.

Everyone is entitled to their own opinion of certain things and i'm not knocking that. I have my own opinions and thoughts, others will have theirs.
Each to their own.


Jon

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Charles uk
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Re: Upset century

Postby Charles uk » Sat Sep 02, 2017 6:18 pm

Jon if you had an Aston Martin DB5 in mint condition, would you run it on the oil you would use in a 2 year old Honda Jazz, NO YOU WOULDN'T !

The same rules apply with your Seagull!

As for your Seagulls not having a problem, how many of yours run for more than 10 hours a year, semi & fully synthetic 2-stroke oils are designed for modern engines that have NO or very few plain bearings (ball race mains with needle little & big ends).

If your going to recommend the use of a modern lubricant you also have to add a warning that it might not be the best lubricant for a tired 50 year old Seagull & could possibly shorten it's life expectancy!
Make it idiot proof and someone will make a better idiot.

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Re: Upset century

Postby headdownarseup » Sun Sep 03, 2017 12:18 am

As i said before, this is and has always been my choice when it comes to oils. It's not everybody's choice i fully understand that. And as always if anyone is not sure, stick with what you know best.

As for db5's, if i was lucky enough to own one then yes i would DEFINITELY use a modern oil. Do you know why i'd use a modern oil compared to an older mineral type?

I'll tell you shall i!

Modern oils by definition have additives in them, which by and large go a very long way to preventing and controlling wear and tear in the first place. They have shear stabilisers blended into them which helps the oil cling to moving parts better than older mineral oils. Mineral oils in very simple terms are generally a base oil refined from the raw stuff that's pumped out of the ground and cleaned up a bit. Don't get me wrong, it's good but there is better stuff out there to choose from that can help an older engine survive for longer without the need for an expensive rebuild. Old Astons or vintage seagulls, i see nothing wrong in using a modern form of lubrication. If anything quite the opposite.
Technology and research has moved on from the old days and old thinking and a lot of you older guys are not too keen to change to the modern way of thinking just yet. I understand that. Far be it from me to pressurise anyone into thinking that my way is the best way. Go and do your own research and make up your own mind over this.

A typical semi-synthetic oil is a blend of ingredients often found in older mineral type oils but with some special additives to improve its lubricity and general service life. That and some careful blending to achieve the different grades or thicknesses for hot and cold temperatures.

A typical fully synthetic is far removed from any base oil from which the blended semi-synth types are formulated. In some cases these oils far exceed the original manufacturers recommendations when it comes to specifications. In a lot of cases they'll comfortably match or better still out-perform many older oils.

So, the bigger question here is how good is a modern oil compared to an older oil. Well for my money the modern type wins every time, even if it is an old and highly prized db5 or a vintage seagull with slack crank bushes and dubious compression values. I shall still use a semi-synthetic oil in all of my seagulls thanks all the same.


You can stick to what you know Charles, i have no problem with that.
I'm going to stick with what i know and what i've seen with my own eyes.


My apologies to red42hj for hijacking his post with this.
Sorry dude.



Jon

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Re: Upset century

Postby Charles uk » Sun Sep 03, 2017 12:41 am

Jon doesn't the Aston use 50 grade oil & the Honda 5W30, with that in the Aston you'd have very low oil pressure, no matter how many sexy additives.
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Hugz
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Re: Upset century

Postby Hugz » Sun Sep 03, 2017 2:15 am

This old bugger uses penrite synthetic oil in his 90's Saab turbo as mineral oil tends to clog up the oil intake filter causing low oil pressure and motor grenading. Which is totally irrelevant to the Seagull discussion.

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Charles uk
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Re: Upset century

Postby Charles uk » Sun Sep 03, 2017 8:46 am

The point of these posts Hugo are that it might be better/safer to follow the OE manufacturers recommendations rather than the new improved hype of an oil that was designed for a very different job spec!
Make it idiot proof and someone will make a better idiot.

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Re: Upset century

Postby Keith.P » Sun Sep 03, 2017 10:14 am

I saw a post not long ago on facetube , someone asking what oil and mix to use on his old motor, most use modern TC-W3 type oils, I said use the manufactures recommended fuel mix, but a lot of people were saying as modern oils are so good you can use 25:1 rather than say 16:1, someone piped up that he uses 25:1 on all has 20's and 30's motor.
I myself only use 10:1 oil mix, what ever make of oil I use its always 10:1.
The wartime recommendation was M160 oil which was the military version of straight 30, so it seems.

red42hj
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Re: Upset century

Postby red42hj » Sun Sep 03, 2017 10:59 am

I'm glad to be able to say that my engine is now running! Unfortunately, I can't tell what the problem was because I did a number of things to it. I do suspect the spring though as the end of it that does the least movement was rusty;( leading to me breaking it on removal.) All that remains now is a proper test on the boat,and an inspection of the spark plug after.
Interesting thread on the oil issue. I have converted it to 25:1 a year ago and it ran fine, but I might still put it back to 10:1 next season since the amount of oil I bought was not a lot by the end of the season. I use a good grade of marine 2 stroke oil now. I had originally used 2t I had left over from motorbikes. I didn't realise at the time that the marine grade ran cooler. The exhaust note changed immediately. Thanks to all input; until the next problem.............Red.

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Re: Upset century

Postby pat777 » Sun Sep 03, 2017 11:15 am

Charles uk wrote:These powerheads were designed to run a 30 weight engine oil fuel oil mix

All of the pre 25:1 Seagulls had the same bearing clearances from 1931 up to the 25:1 era,


So just for clarity for newbies, when you say a "30 weight engine oil", Is that SAE 30 that you are referring to.

sae 30.jpg
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Charles uk
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Re: Upset century

Postby Charles uk » Sun Sep 03, 2017 11:55 am

Yes something very similar to SAE 30 but with less modern additives, there are several Kiwi Seagull racers who swear by a SAE 30 2-stroke mix & their results seem to prove their point!

It would be fascinating for all, if someone with suitable measuring equipment (GPS & Digital rev counter) would run a series of semi-scientific performance tests to see if the Kiwi's claims are valid, & to see if the smoke issue is accurate or an old wives tale.

A sort of before & after scenario on a 50 plus year old Seagull.
Make it idiot proof and someone will make a better idiot.

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Re: Upset century

Postby headdownarseup » Sun Sep 03, 2017 11:59 am

I'm starting another thread on this so we don't hijack this guys posting any more.

Follow me

Jon

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Re: Upset century

Postby pat777 » Sun Sep 03, 2017 12:29 pm

Jon I can't find your new thread. If you can post a link to it please.

Thanks Charles,
Yes something very similar to SAE 30 but with less modern additives


So if not SAE 30, do you know a brand name of the 30 weight oil that I could look up please?


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