The points are adjusted by rotating the flywheel until the points gap is at maximum,then loosening the large screw securing the plate with the fixed contact.The small screw can then be turned,it works like a cam and will open or close the points gap.When the gap is correct you then lock the fixed contact plate by tightening the large screw,the small screw will then remain fixed in position.
The ignition timing is not adjustable,it was set during manufacture.The magneto base plate that carries the points and ignition coil is locked in the correct position on the crankcase spigot by means of a long radially orientated screw on the underside of the base plate.As Charlesp said,if you don’t want to remove the flywheel to check,remove the locking screw and with a suitable piece of wire inserted in the screw hole rotate the base plate until you feel the locating hole in the crankcase spigot.If you look over the top of the flywheel towards the fuel tank the black HT lead connector should be at about the 8 o’clock position when correct.Mark the position and replace the locking screw,you should be able to feel when it is located in the hole,then tighten fully.
The points gap and ignition timing should now be correct.
Hope this clarifies matters.
Steve
40 Plus - poor starting,what to do next?
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
I have managed to undo the screw, and had to remove the flywheel in order to get a good grip on the base platein order to free it. That is now loose, and I have identified the hole in the collar at the top of the crankcase. But I find that the screw was correctly inserted all along.
The fact remains that the contact points do open at 50 degrees BTDC, ie about 3" back around the circumference of the flywheel. I cannot see what can possibly have altered to bring that about, but it must be wrong. No engine has that degree of ignition advance - it is hardly surprising that it would only run at all at speed., and be incapable of firing usefully at cranking or idling speed.
Is it possible that the wrong flywheel has been substituted, one with the eccentric cam in a different position?
Should I drill a new hole in the collar, so that the contacts do open at TDC?
Or is the cam removeable from the flywheel? I notice six recessed screws, but they don't look very moveable. If it were possible to remove the cam it could be shifted round by 60 degrees, which would give a firing position much nearer to TDC.
Any advice please?
The fact remains that the contact points do open at 50 degrees BTDC, ie about 3" back around the circumference of the flywheel. I cannot see what can possibly have altered to bring that about, but it must be wrong. No engine has that degree of ignition advance - it is hardly surprising that it would only run at all at speed., and be incapable of firing usefully at cranking or idling speed.
Is it possible that the wrong flywheel has been substituted, one with the eccentric cam in a different position?
Should I drill a new hole in the collar, so that the contacts do open at TDC?
Or is the cam removeable from the flywheel? I notice six recessed screws, but they don't look very moveable. If it were possible to remove the cam it could be shifted round by 60 degrees, which would give a firing position much nearer to TDC.
Any advice please?
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
I've just had another look. With the screw engaged in the hole the black HT connector is at about 7 o'clock. To make the points open at TDC the base plate has to be turned so that the connector is at 9 o'clock.
Should I simply try that and see? Will the screw hold well enough even if not engaging in the hole in the collar?
Should I simply try that and see? Will the screw hold well enough even if not engaging in the hole in the collar?
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Charles UK
If the timing is the same as a century, the timing is 23 degrees before TDC.
The magneto base plate locking screw must be in the locating indentation in the top half of the crankcase & the points shoub be set at 20 thousands of an inch as is the spark plug.
Every other Seagull fitted with this ignition starts & runs when this is done!
If you set everything in the right place& it still won't start then one of the components must be faulty.
The magneto base plate locking screw must be in the locating indentation in the top half of the crankcase & the points shoub be set at 20 thousands of an inch as is the spark plug.
Every other Seagull fitted with this ignition starts & runs when this is done!
If you set everything in the right place& it still won't start then one of the components must be faulty.
I’ve just checked the timing on one of my forties.It has Wipac ignition but since the whole system is interchangeable with Villiers it should make no difference.Using a marked rod through the spark plug hole, and in contact with the piston crown, the points start to open at approximately one quarter of an inch before TDC.Yours should give a similar result.
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
No, nothing like 1/4".
Just to be absolutely clear:
I have the screw properly located in the hole in the collar. The points are set at 20 thou. I locate TDC by sticking a pencil through the plug hole, and make a mark on the flywheel and a corresponding line on the base plate. I then wind the flywheel back until the moment when the points are only just opening. I have at that moment turned the flywheel back from the mark an angle of 50 degrees, or 3" of circumference.
Something appears to be very wrong - but what?
Just to be absolutely clear:
I have the screw properly located in the hole in the collar. The points are set at 20 thou. I locate TDC by sticking a pencil through the plug hole, and make a mark on the flywheel and a corresponding line on the base plate. I then wind the flywheel back until the moment when the points are only just opening. I have at that moment turned the flywheel back from the mark an angle of 50 degrees, or 3" of circumference.
Something appears to be very wrong - but what?
I was going to check the timing on mine, which I have had from almost new, tomorrow. It is also the Wipac ignition system but as you say they were a direct replacement for the previous Villiers system.
I find it hard to believe that the timing is as much as 23 degrees before TDC.
Regarding the positioning of the cam within the flywheel. What part of the assembly is keyed to the crankshaft? If that is the cam and the body of the flywheel is bolted to it with the six countersunk screws then repositioning it within the flywheel will not change the timing. What it will do is alter the positioning relative to the pole pieces in the flywheel which may be important.
The flywheels were always supplied as complete assemblies and that also applied to Villiers engines on lawn mowers etc and small motor bikes
I find it hard to believe that the timing is as much as 23 degrees before TDC.
Regarding the positioning of the cam within the flywheel. What part of the assembly is keyed to the crankshaft? If that is the cam and the body of the flywheel is bolted to it with the six countersunk screws then repositioning it within the flywheel will not change the timing. What it will do is alter the positioning relative to the pole pieces in the flywheel which may be important.
The flywheels were always supplied as complete assemblies and that also applied to Villiers engines on lawn mowers etc and small motor bikes
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
That's very true Vic, I wasn't thinking straight.
So if you are surprised at 23 degrees advance, you do agree that my 50 degrees must be wrong?
Are all Seagull flywheels interchangeable and with the same relationship of cam position to keyway? Could someone have used an incorrect flywheel?
Are all the points sets the same, or do some have a different geometry and bear on a different sector of the cam?
So if you are surprised at 23 degrees advance, you do agree that my 50 degrees must be wrong?
Are all Seagull flywheels interchangeable and with the same relationship of cam position to keyway? Could someone have used an incorrect flywheel?
Are all the points sets the same, or do some have a different geometry and bear on a different sector of the cam?
50 degrees is way out.
All the flywheels are interchangeable - that is assuming the type is correct.
But the crankshafts are not. The Century and the forty crankshafts have the keyway cut at a different spot on the shaft, which gives you a completely wrong timing if you fit the wrong crank. I can't tell you what the difference is because it's very cold and dark outside, and my workshop has no mains electricity.
But the 23 degree figure is correct. To be absolutely precise it's 23 1/2 degrees.
If you set the baseplate correctly as suggested, and then adjust the gap when the points are at their widest, then check the timing angle, it's just possible that things may look a little better.
All the flywheels are interchangeable - that is assuming the type is correct.
But the crankshafts are not. The Century and the forty crankshafts have the keyway cut at a different spot on the shaft, which gives you a completely wrong timing if you fit the wrong crank. I can't tell you what the difference is because it's very cold and dark outside, and my workshop has no mains electricity.
But the 23 degree figure is correct. To be absolutely precise it's 23 1/2 degrees.
If you set the baseplate correctly as suggested, and then adjust the gap when the points are at their widest, then check the timing angle, it's just possible that things may look a little better.
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
No, I've re-checked, the points (20 thou) open at 50 degrees BTDC (3" of flywheel circumference). Measured in terms of actual piston movement, that is when the piston is still 5/8" below TDC.
So it seems one explanation could be that it has the wrong crankshaft, ie one from an engine that fits in all other respects, but has the keyway cut in a different position.
A bizarre explanation, but what other is there?
I'm thinking now of just putting it back together and adjusting the timing to TDC regardless of the alignment hole, and just tightening the screw against the plain section of the collar. Would that hold?
Is the 23 degrees advance figure certain? Even that sounds a lot for a relatively slow running engine.
So it seems one explanation could be that it has the wrong crankshaft, ie one from an engine that fits in all other respects, but has the keyway cut in a different position.
A bizarre explanation, but what other is there?
I'm thinking now of just putting it back together and adjusting the timing to TDC regardless of the alignment hole, and just tightening the screw against the plain section of the collar. Would that hold?
Is the 23 degrees advance figure certain? Even that sounds a lot for a relatively slow running engine.
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Charles UK
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
Yes, that'll be the day!
OK, I'll try setting the timing at 23, or failing that TDC, and just ignoring the location hole in the collar.
A final thought, are the contact breaker units interchangeable? I do notice that mine has quite a long arm on the protruding section that has the fibre heel. It reaches quite a long way round the crank cam, ie advanceing the ignition. A shorter arm would react later in the rotation. Could an incorrect unit fit, but throw the timing out?
OK, I'll try setting the timing at 23, or failing that TDC, and just ignoring the location hole in the collar.
A final thought, are the contact breaker units interchangeable? I do notice that mine has quite a long arm on the protruding section that has the fibre heel. It reaches quite a long way round the crank cam, ie advanceing the ignition. A shorter arm would react later in the rotation. Could an incorrect unit fit, but throw the timing out?
Have a look at this ignition set:
It's actually from an LS, but apart from the lack of a protective flange around the baseplate circumference it's identical to a 1964 model. I didn't have a complete one of the identical vintage to hand without dismantling something, and it's cold out there!
You can see that the arm is quite long, and does as you say reach quite a long way round.
For a Seagull with Villiers ignition of this type there's only one points set.
A couple of questions...
Are you measuring your gap with the points fully open? British Seagull engineers would frequently close the gap down to as little as 12 or 13 thou to compensate for timing errors on earlier motors.
Are you confident that the baseplate is in the correct position? The securing screw will be pointing directly forward when the motor is on the transom.
What is the serial code/number of your motor? (I think it's important that we make sure of this - some of the earlier ones will need the ignition closing down). I suspect we're relying on the tank instructions where we have no guarantee that the tank is the original! It's probably right but it's as well to check.
I popped down to the workshop to take that photo, and I don't have a pair of crankshafts to hand, so I can't photograph them. But I can tell you that the position of the baseplate on a Century is very different. The British Seagull manual has a diagram opposite sheet No16 that illustrates the difference - it looks to be about 120 degrees.
I can confirm once again that the correct timing for a Seagull is 23 1/2 degrees. That's near as dammit a corner of a sheet of paper folded along thengle, then folded again ( if you have no protractor handy).
I am more and more convinced that timing is the problem. But it's one thing being convinced by correspondence - it's entirely another thing to have the offending beast on your workbench.
It's actually from an LS, but apart from the lack of a protective flange around the baseplate circumference it's identical to a 1964 model. I didn't have a complete one of the identical vintage to hand without dismantling something, and it's cold out there!
You can see that the arm is quite long, and does as you say reach quite a long way round.
For a Seagull with Villiers ignition of this type there's only one points set.
A couple of questions...
Are you measuring your gap with the points fully open? British Seagull engineers would frequently close the gap down to as little as 12 or 13 thou to compensate for timing errors on earlier motors.
Are you confident that the baseplate is in the correct position? The securing screw will be pointing directly forward when the motor is on the transom.
What is the serial code/number of your motor? (I think it's important that we make sure of this - some of the earlier ones will need the ignition closing down). I suspect we're relying on the tank instructions where we have no guarantee that the tank is the original! It's probably right but it's as well to check.
I popped down to the workshop to take that photo, and I don't have a pair of crankshafts to hand, so I can't photograph them. But I can tell you that the position of the baseplate on a Century is very different. The British Seagull manual has a diagram opposite sheet No16 that illustrates the difference - it looks to be about 120 degrees.
I can confirm once again that the correct timing for a Seagull is 23 1/2 degrees. That's near as dammit a corner of a sheet of paper folded along thengle, then folded again ( if you have no protractor handy).
I am more and more convinced that timing is the problem. But it's one thing being convinced by correspondence - it's entirely another thing to have the offending beast on your workbench.
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
Thanks Charles. That's almost exactly how mine looks (minor differece at the adjustment point - small screw). It has the same quite long arm, so that must be OK.
I've tried closing the gap. It obviously makes some difference to the timing, but nowhere near enough to bring 50 down to 23 degrees.
The locating hole in the collar does indeed point forwards - presumably that really is set at the factory. It's just that with the base plate then aligned on that hole, the timing is wrong. It can only be caused by an incorrect crankshaft with a different keyway position, or else a flywheel with a different cam position.
I'll try it on 23 degrees tonight and report back.
Thanks
Cliff Pope
I've tried closing the gap. It obviously makes some difference to the timing, but nowhere near enough to bring 50 down to 23 degrees.
The locating hole in the collar does indeed point forwards - presumably that really is set at the factory. It's just that with the base plate then aligned on that hole, the timing is wrong. It can only be caused by an incorrect crankshaft with a different keyway position, or else a flywheel with a different cam position.
I'll try it on 23 degrees tonight and report back.
Thanks
Cliff Pope
I’ve compared a Forty with a Century and the position of the flywheel keyway is noticeably different.Looking over the flywheel towards the tank,the keyway on the Forty is roughly at 7 o’clock at TDC.The Century is at roughly 10 o’clock at TDC.The difference is so obvious that exact measurement is not required.