Water testing 40+ and Silver Century

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haventaclue
Posts: 145
Joined: Thu May 01, 2014 11:09 am
Location: Donegal

Water testing 40+ and Silver Century

Post by haventaclue » Fri Nov 01, 2019 10:59 pm

So I was water testing the auld Picton that I'm "restoring",so decided to kill two birds with the one stone and finally take the gulls out for a spin and test them as well.
40+ ran great,didn't push the 15' planing hull very well,but hey,it worked.
Silver Century not so good,even with nice shiny Amal carb.Both have Wipac 2 ignitions.Fuel was 10:1 for both.
It would run but get the revs up. And if I rattled the tickler,it would pick up a little but not much.
So back home,I cleaned everything,from tank to carb jets.A wee bit of gunk but nothing that would restrict fuel,checked points and plug gaps to .5mm.
Fired her up in the tank,no improvement,would only stay running if I left the choke on.
Twist grip opens throttle all of the way as far as I can see, points cleaned and set to .5mm, plug cleaned and set to .5mm, compression 60psi on an old tester which I know is reading low,about 10 - 15 psi.I compared it before with new tester belonging to friend.
Only anomaly is the points spark speaks in forked tongue,strong and blue but as if it hits the outer edge of the points face with a gap in the middle of the spark. Wipac on it's way out? Now I had noticed this before the outing.
Another question,if the Amal carb was jetted for 25:1,would this affect performance as the fuel I was using was closer to 8:1 than 10:1,TCW-3 oil.
And on that,I have,brand new in the packet,conversion kit 25:1jet for Amal 46N.What is the tell to know which is 25:1 and which is 10:1, as the one in the packet looks exactly like the jets in both carbs I have?
I though I had videoed it but me and touch screens don't get on too well,so it seems I didn't record anything :cry: Any advice greatly appreciated.

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Nudge
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Location: Auckland, New Zealand

Re: Water testing 40+ and Silver Century

Post by Nudge » Sun Nov 03, 2019 12:09 am

You will have to take the jets out.
Look at the number on the side of the jet. I think one will have 20 on it and the other 40 or 45. Im not sure what one is the 10:1 v the 20:1 I would need to look in the book for that (if it is in there I have not looked for that)
"THE KING OF BLING"!
Is it better to over think, than not think at all?

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Charles uk
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Location: Maidenhead Berks UK

Re: Water testing 40+ and Silver Century

Post by Charles uk » Sun Nov 03, 2019 12:34 am

40 = 25:1
45 = 10:1
50 = 10:1 cold climate.
Make it idiot proof and someone will make a better idiot.

haventaclue
Posts: 145
Joined: Thu May 01, 2014 11:09 am
Location: Donegal

Re: Water testing 40+ and Silver Century

Post by haventaclue » Sun Nov 03, 2019 9:19 am

Thank you gentlemen,will have a look at them later

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Oyster 49
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Location: Derbyshire, UK

Re: Water testing 40+ and Silver Century

Post by Oyster 49 » Sun Nov 03, 2019 12:54 pm

Have you got the correct prop fitted? If you have an incorrect prop with too coarse a pitch then the engine will not be able to drive it.
I had the same problem on a FPC engine, that had a 40 plus direct drive prop fitted in error.

haventaclue
Posts: 145
Joined: Thu May 01, 2014 11:09 am
Location: Donegal

Re: Water testing 40+ and Silver Century

Post by haventaclue » Sun Nov 03, 2019 1:45 pm

Thanks for the reply Oyster49,yup correct prop.And got sorted.
Checked the jet, No.40,thinned the mix out and she ran right.
I knew a richer mix might have an effect on it,but to the point that it needed the choke to keep running didn't enter my head.
So I need to bring two different mixes next time,the Spring.
Thanks for all advice

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