Final update:
I've just started it from stone cold. It fired on the second pull with no difficulty (full choke and full throttle), and very quickly settled down to a nice even idle. It revs up with no hesitation.
I tried experimenting by turning the base plate, but it is clear that about 10 degrees BTDC is the optimum timing point. That gives the fastest and smoothest idle. Turning it back to the point where the screw would engage in the hole causes it to run erratically and then stall. It won't restart in that position, but does instantly if turned back to the 10 degree position.
So that's where I'll leave it set. I suppose a final refinement would be to make a new pip in the collar just to locate the base plate properly, but it seems to stay put just by screwing the bolt up tight against the collar.
40 Plus - poor starting,what to do next?
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
Ign problems
Strikes me reading all this that there is a very good chance that the ignition timing could be way out beacuse the points are not correct.....
Slack off the backplate screw again till you can turn the backplate.
Now gently screw it in till it you feel the crankcase. Whilst maintaining slight pressure on the screwdriver, rotate the baseplate. When you get to the correct position the screw will go in another 3 turns. timiing is then fixed as it should be.
Re the points. They alter the timing! Bet yours are way out!
The flywheel has a key locating it on a keyway on the crankshaft. There is a cam built into the flyywheel, provided the key is in place, and you can feel it with a probe if you remove the nut and rope pull, the points should start to open just before the piston reaches the top of the bore, feel for it with a biro through the plug hole.
Undo the larger of the two screws just enough to be able to move the points with the smaller screw. set the points to 20 thou gap, ensure they are clean first with 300 grade emery, or you are wasting your time!
Carefully tighten the large screw and recheck the gap. It may well have moved, try again, if too tight now open up slightly more than 20 and re tighten, check again. It should not take many tries to get it right. I know it is a pain to have to work through the holes in the flywheel, but you have to as the cam is attached to it.
Spin the motor over with the flat of your hand with the plug held against he block, you should see the spark in a darkened garage, might be difficult in bright sun.
If a weak white or yellow spark, it could well be the condensor. The Villiers condensor is an expensive beast, £38! Some have had good results replacing with a car type capacitor screwed down to the base plate next to the points housing....
hope this helps.
John
SOS
Slack off the backplate screw again till you can turn the backplate.
Now gently screw it in till it you feel the crankcase. Whilst maintaining slight pressure on the screwdriver, rotate the baseplate. When you get to the correct position the screw will go in another 3 turns. timiing is then fixed as it should be.
Re the points. They alter the timing! Bet yours are way out!
The flywheel has a key locating it on a keyway on the crankshaft. There is a cam built into the flyywheel, provided the key is in place, and you can feel it with a probe if you remove the nut and rope pull, the points should start to open just before the piston reaches the top of the bore, feel for it with a biro through the plug hole.
Undo the larger of the two screws just enough to be able to move the points with the smaller screw. set the points to 20 thou gap, ensure they are clean first with 300 grade emery, or you are wasting your time!
Carefully tighten the large screw and recheck the gap. It may well have moved, try again, if too tight now open up slightly more than 20 and re tighten, check again. It should not take many tries to get it right. I know it is a pain to have to work through the holes in the flywheel, but you have to as the cam is attached to it.
Spin the motor over with the flat of your hand with the plug held against he block, you should see the spark in a darkened garage, might be difficult in bright sun.
If a weak white or yellow spark, it could well be the condensor. The Villiers condensor is an expensive beast, £38! Some have had good results replacing with a car type capacitor screwed down to the base plate next to the points housing....
hope this helps.
John
SOS
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
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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
"Who cares here's a running Seagull. Magic!"
Exactly. It was aquired for next to nothing, and at first seemed like a lifeless lump. Now it starts and runs well, and next sunny day (!) I hope to have a go playing on the river. When the bigger boat is finally finished and re-launched, next year or the year after, I'll have a good little tender dinghy and a working outboard.
Exactly. It was aquired for next to nothing, and at first seemed like a lifeless lump. Now it starts and runs well, and next sunny day (!) I hope to have a go playing on the river. When the bigger boat is finally finished and re-launched, next year or the year after, I'll have a good little tender dinghy and a working outboard.
I have actually been having a play with a Villiers unit, and John is quite right - the points gap can appreciably alter the timing. FV/Forty or Centurty - the principle's the same.
What I can't replicate is a 50 degree advance..
Sorry my pic was an FV unit (but it is near as dammit the same!) - but you've seen my workshop recently and can appreciate the difficulty of laying my hands on anything easily! Maybe after all I should have a bit of a tidy up...
What I can't replicate is a 50 degree advance..
Sorry my pic was an FV unit (but it is near as dammit the same!) - but you've seen my workshop recently and can appreciate the difficulty of laying my hands on anything easily! Maybe after all I should have a bit of a tidy up...
Last edited by charlesp on Mon Nov 13, 2006 10:41 am, edited 1 time in total.
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Clifford Pope
- Posts: 39
- Joined: Sun Nov 05, 2006 1:37 pm
- Location: West Wales
One thing that might possibly be indicative of something; everyone has talked of a dimple or slight depression in the crankcase collar, and 3 turns of the screw to lock the screw in it.
Mine has a hole the size of the screw going all the way through. Once located, the screw turns a further 1/4 " or more. There is actually nothing to tighten up against until it reaches the head or runs out of thread.
The end of the screw is flat, which means it tightens securely against any point on the collar circumference. Fortunately the "correct" place (by experiment) is some distance round from the hole, so there is no problem of needing to overlap the screw with half the hole.
I too experimented with the timing effect of varying the contact gap, but found it was impossible to adjust a 50 degree advance down to anything sensible even setting the gap at a bare 1 thou.
Mine has a hole the size of the screw going all the way through. Once located, the screw turns a further 1/4 " or more. There is actually nothing to tighten up against until it reaches the head or runs out of thread.
The end of the screw is flat, which means it tightens securely against any point on the collar circumference. Fortunately the "correct" place (by experiment) is some distance round from the hole, so there is no problem of needing to overlap the screw with half the hole.
I too experimented with the timing effect of varying the contact gap, but found it was impossible to adjust a 50 degree advance down to anything sensible even setting the gap at a bare 1 thou.