Special precautions running in new piston/ piston rings

[pat777]

We're currently putting back together a few gulls with new pistons and piston rings. Just wondering should we take any special precautions when running them in/ starting them for the first time after reassembly? Is it best to run them in a barrel of water on low revs for a certain time period to give the rings a chance to bed in?

Am I right in thinking that the seagulls when set up as per factory settings will need to be set to around 3/4 throttle to start them. Is there any point trying to start them at a lower throttle setting or will they just not fire up? Obviously the water flow won't be too good at the lower throttle setting so I guess the revs will have to be increased to take this into account. Any advice on the subject appreciated.

Cheers Pat

[chris]

I think according to the seagull people there are no running in procedures, just start it up and run it as for normal use.

[pat777]

Thanks chris, that's good to know. I just wasn't sure if I needed to take it easy with the outboard after rebuilding. Thanks for clearing it up for me. Full speed ahead captain!

Cheers Pat

[headdownarseup]

steady on PAT.

err on the side of caution here. use an oil rich fuel mixture for the first tank full of fuel. (8-1 or 10-1) or greater and use maybe 3/4 throttle setting. vary the throttle setting from just off idle (so the water flow isn't stopped) up to around 3/4 throttle. this should allow the rings to bed in well enough.
after the tank full of oil rich fuel has been used, then go back to your normal fuel mix. just like "running in" an old 2 stroke motor bike.

as always, the best place to "run in" your freshly built motor would be on the back of your boat, not the bin. (you need the motor under some sort of loading)
gently does it before you go flat out!

jon

[chris]

I thought most seagulls the normal fuel mix was 10/1 and they run quite happily at 3/4 throttle all day, Don't 2 stroke bikes run harder and hotter than a seagull so would need running in.

[headdownarseup]

chris
yes indeed, seagulls DO run quite happily at 10-1 fuel mix. BUT, pat hasn't said how old his motor is yet.
from memory, most seagulls made before 1967 (ish) SHOULD ALWAYS run on 10-1 fuel mix. (or even 8-1 on pre 1950 motors)
after 1967 25-1 fuel mix can be used.
BS from 1978 onwards encouraged all their motors to run 25-1.
the differences are in the crank bushes apparently. some longer and some shorter to cope with more or less oil content.
HOWEVER, there are lots of stories around that say loads of people have run old motors (pre 1967) for years with no trouble at all using 25-1 mix. depending on whether the motor is 40 or century, with villiers or amal carb.
villiers carb has a small needle jet adjuster on the throttle slide(turn the screw down to lean the mixture but no more than 2 turns down from flush with slide top)
amal carb needs a jet swapping.
later amal 416 runs quite well at 10-1 0r 25-1. i havn't tried it yet.

going back to "running in" a freshly re-built motor, i always err on the side of caution. better to have too much oil in the fuel for the first tank full. the worst it will do is foul up a plug and run a bit smokey.
i always carry some spares whenever i go out on the boat, spanners scewdrivers plugs etc. just in case!
once its "run in", then go back to the proper fuel mix dependant on the age of your motor.

hope this clears things up a bit?

jon

[headdownarseup]

bike engines.

yes they DO run a lot hotter, and as a result, have slightly different oil requirements to cope with greater temperatures and compression. (low compression on a seagull)
and yes they DO run harder and faster then the dear old seagull.
3000 rpm wot on a seagull (thereabouts)
bike engine, anything up to maybe 15-20,000rpm. (screeming) some ex-works gp 2 strokes from the 60's and 70's were regularly reaching these rev limits! sometimes even higher?
different kind of power all together.
think of a seagull as more of a tractor, not a high performance sports car!

jon

[pat777]

Thanks Jon, I'll run them in easy in that case. I guess there is no point taking a chance damaging anything. I'll either run them with the prop off or not in gear on the clutched models if I'm running them in the barrel.

Cheers Pat

[Stelios_Rjk]

In a manual I think I have read that it was suggested to run them hard in the beginning. Possibly to remove any imperfections on the bearings. But never over rev without the prop on. It will get to more rpm than suggested and that could to a nice bang!

[headdownarseup]

the best way, if you've only got a bin to use, is to vary the speed at which you run the motor for the first 30 mins. gently at first then increasing the revs SLOWLY.
try and vary the revs for the next 30 mins as mentioned earlier from just above idle (to keep the water flowing) up to around 1/2 throttle. don't over do it ESPECIALLY if you dont have a prop fitted. as STELIOS has said, you can quickly over rev the motor (because it's not under any load) and wreck all the hard work you've spent doing. what you can end up doing in this case is glaze the bore because its getting too hot. far better as mentioned, use lots of oil in the mix to help things a bit. remember that at a constant throttle setting there wont be a lot of oil present at low speeds (if using 25-1) until you "gun" the motor which then surges a rich mixture throughout the block and cases. which is why i said vary the speed gently at first then building up to 1/2 to 3/4 throttle but no more ESPECIALLY WITH NO PROP.
better to run in on the boat(if you can) instead of a bin. better loading on the motor to get the rings and bore to settle down if that makes sense? and a more constant waterflow. (quite restricted sometimes in a bin)
does that all make sense now!
gently at first then build up slowly.
spent a long time before with bike engines and minimotos. my little minimoto is 46cc and 11hp. (watercooled) pulls wheelies coming out of corners! tricky but fun to ride.
of course, seagulls are more "agricultural" shall we say, but the principals are pretty much the same. engine life can be directly related to the "break in period". do it well and the motor should last for years, do it badly and who knows how long it will last?

hope that clears things up for you!

jon

[pat777]

Thanks Stelios_Rjk and Jon for the further information on running in the outboards after changing the piston and rings. I guess it will be best to get the boat out on the water to run the outboards in properly. So once I get them started I'll decrease the revs for a bit, whilst keeping the water pumping and then vary the revs up and down but I won't go past 3/4 throttle until they are well run in. (Have to stick to the 4 mph speed limit on the canals in any case)

Thanks for the detailed replies,

Cheers Pat

[lakeviewlad]

Hello Pat,
What age are your motors? If ye run them on proper mixture avoiding full revs then they should be fine providing the cooling system is working ok. The British Seagull is hardly a Bristol Hercules....haha!
I'm near Upper Lough Erne,where are you? I have some interesting motors in my collection. Have you any rare motors? Brian.

[JERSEYMAN]

Occam's Razor states that by nature we over complicate things, Very True, we do, we are talking Seagull Outboards here, they were very cleverly designed to tolerate and endure an incredible amount of abuse, a few basics have to be followed for them to be reliable but nothing mentions that you should pussyfoot in the running in procedure, quite the opposite in fact.

Use common sense, you'll be alright, it's after all only a lowly tuned Seagull outboard.

I once had to come back against the tide with a silver century that stopped pumping water, it was running over 1/2 throttle for an hour with only steam coming out but it got me home, not many modern motors would handle that, respect.
Stripped and inspected showed that the water delivery pipe had blocked at the top where it meets the block and only letting very little water into the jacket, the internals showed very little signs of heating, wear or failure, these motors are far more rugged than we give them credit for, built in a different era.

[pat777]

Hi Brian

All my motors are on 10:1 mix. I have a couple of 102's, a couple of centuries and a forty plus. Most of them are bitsa motors, that have been played around with by previous and current owners switching around parts off different motors to make up a working motor. 102 AD 1953, 102 THC 1960's, LLS 1964 Century, WS 1977 Silver Century and GFP 1977 Forty Plus. They are all fairly rough looking motors, no fancy paint jobs, nor too many shiny parts, plenty of dents and scratches and oil leaks. So in answer to your question, nothing rare or exciting or worthy of note. The nearest body of flowing water to me is the river Barrow.

This is a picture of the first one I bought, you've probably seen it before in previous threads. It gives some indication of the quality of my motors. Ah sure as long as they work and get me where I want to go.

[pat777]

Occam's Razor states that by nature we over complicate things, Very True, we do, we are talking Seagull Outboards here, they were very cleverly designed to tolerate and endure an incredible amount of abuse, a few basics have to be followed for them to be reliable but nothing mentions that you should pussyfoot in the running in procedure, quite the opposite in fact.

Use common sense, you'll be alright, it's after all only a lowly tuned Seagull outboard.

I once had to come back against the tide with a silver century that stopped pumping water, it was running over 1/2 throttle for an hour with only steam coming out but it got me home, not many modern motors would handle that, respect.
Stripped and inspected showed that the water delivery pipe had blocked at the top where it meets the block and only letting very little water into the jacket, the internals showed very little signs of heating, wear or failure, these motors are far more rugged than we give them credit for, built in a different era.

I'm certainly guilty of over complicating things all right. It was the simplicity of the seagull outboard that attracted me to them in the first place, easy to work on and of course plenty of spare parts available, well most parts anyway. I love stories like that of the trusty seagull getting you home on a wing and a prayer. I'd be afraid of my life to run one of them for more than a minute without a clear flow of water coming from the telltale for fear of the motor seizing up, I guess it just goes to show the abuse they can withstand. Most of my motors have the appearance of being well used and abused by previous owners. Hopefully the little bit of tender love and care they are getting at the moment will keep them reliable for years to come.

Cheers Pat