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Setting clearance on contacts

Posted: Wed Feb 18, 2009 11:47 pm
by gav1189
Help! I recently bought a small day/fishing boat, with it came an old seagull. I was told it was a good runner but had been sitting for a while. When i eventually got round to having a look at it it did not want to start!

I then, perhaps a bit foolishly, decided to strip and rebuild it myself. Upon stripping the engine i was surprised that the piston and cylinder were in very good condition. The only major thing was the waterways. All in all i spent a good hour with the aid of a 5mm drill bit and a screwdriver to clear the lower waterway.

Anyway i then built it back up again replacing the gaskets, gearbox oil, spark plug and throttle cable and hae now found that i hardly ever get a spark, maybe once every 20 pulls - not so good! I tried the method of spinning the flywheel with a drill and socket but had no success. Eventually iv managed to get the flywheels off and have found the clearence at the contacts to be between 0.6 and 1mm. Too big? The thing i cant work out how to do in change the clearance. Am i totally missing something?
Hope someone can help
Cheers, Gav
Oh and its a 1973 or there abouts 40 something.

Posted: Thu Feb 19, 2009 2:19 am
by Ian Malcolm
IIRC it should be gapped 0.020" (~0.5mm). (same as the plug)

I assume, possibly incorrectly that it has a Wipac Magneto.
You loosen the fixing screws for the points assembly and adjust with the piston at or near BDC with the points at their maximum gap. I cant remember if one of the screws is eccentric for adjustment or if its just in a slot and you have to gently lever the points baseplate about to set the gap till you feel a slight drag with your feeler gauge. Tighten everything and re-check the gap and hopefully all will be well.

While you are in there, draw a white business card moistened with methylated spirits through the closed gap (piston at or pretty near TDC). It only takes a single grain of sand in the gap and it will be a nightmare or even completely impossible to start. DONT file the points faces unless they are seriously pitted, that's a last resort before replacement and can do more harm than good unless you have a very light touch.

You don't actually have to take the flywheel off to do all this. there is just enough access through the openings in the top of the flywheel under the cover plate/rope spool.

Posted: Thu Feb 19, 2009 3:09 am
by Charles uk
I hate to say this Ian but I always clean my points with a small piece of wet & dry of what ever grade I can find to hand, usually 400 or 600 grade.

I do this almost as a matter of course, I've only ever had to renew points after the previous owner has adjusted them with a club hammer.

John would be the man to comment on this, as he services other peoples sickly Seagulls all winter, between packing parcels of vital spares destined for warmer climes.

The Seagull points ignitions are as long as they get a little attention every couple of years, are very sturdy components, many of which are reaching pensionable age & are capable of more work than their owners.

I'm speaking of course from personal experiance as I no longer seem to spark as well as I did in my youthfull days!