Silver century running problem

IanLynx · Post by **IanLynx** » Tue Sep 04, 2007 4:09 pm

I have a silver century with a two jet amal carb on it. It has the 25:1 conversion jet fitted as supplied by Seagull.
1 It is a pain to start - usually needing a sniff of WD 40 in the intake before running.
2 It will then run fine but only with the choke flap in place - take the choke off and it will stop - it will run on full throttle but very badly and stops as soon as you reduce throttle.
I have cleaned the tank - set the points to 15 thou and 20 thou. Changed the gap on the plug from 20 to 25 thou. Changed the plug from the 8 com fitted to the Bosch plug that works fine in my older 102. Had the carb off - jets out - soaked in cellulose thinners, blown through. I've even put the 50 power jet in and tried 10;1 fuel. All with no change.

Has anyone any ideas as I seem to have run out?

Ian

Vic · Post by **Vic** » Tue Sep 04, 2007 11:22 pm

It shows the symptoms of a (partially) blocked jet despite your efforts. A solvent like cellulose thinner will not shift everything. You may have to cautiously push something through. I use soft copper wire (fuse wire)

IanLynx · Post by **IanLynx** » Wed Sep 05, 2007 7:45 am

thanks for that Vic - I'll give it a go and post the result later
Ian

niander · Post by **niander** » Wed Sep 05, 2007 7:00 pm

hold it up to the light if the jets are clear you'll see it!
i have this fantastic 240v very powerful air pump[for blowing up tender]
its like compressed air...sorted

Vic · Post by **Vic** » Wed Sep 05, 2007 7:10 pm

hold it up to the light if the jets are clear you'll see it!

You'll see the light through it if it is partially blocked.!

I spent ages trying to get an old Volvo Penta 51 that had had some water in the carb to run properly I could see through the (slow running) jet and could blow through it but it was not until I pushed some thin soft wire through it that I got it properly clear. Then it ran as sweet as a nut.

IanLynx · Post by **IanLynx** » Thu Sep 06, 2007 4:58 pm

Right then - here is the report
1 Removed carb
2 stripped carb (again)
3 looked through jet and I can see light
4 pushed COPPER wire through jet (I was always told not to do that when I first started work on engines)
5 Reassembled everything
6 Put engine in test tank (aren't the council good to give us all wheelie test tanks!)
7 Turned on fuel, closed choke, full throttle pulled cord - nothing
8 Repeat 7 - nothing
9 Changed to half throttle - pulled cord - and its a runner!
10 opened choke - and its still a runner!
11 celebrated with a well deserved cup of tea at the computer to reply
Thanks Vic.

So, even if you can see through the jet try an extra clean with copper wire

Vic · Post by **Vic** » Fri Sep 07, 2007 11:48 pm

I use copper wire because it is unlikely to damage a brass jet. Even so i would not want to do it on a regular basis. Never use a steel wire thats the main point I think.

Anyway pleased to hear its now running.

CatiGull · Post by **CatiGull** » Sun Sep 09, 2007 12:04 pm

Another old 'Gull saved - John - you will have to start a counter on the Main Page someday - another task for the webmaster....