Saving Old Seagulls

Hi, forgive me if this is already posted but I can't find anything
I have a 55 that starts first or second pull, it runs for a couple of minutes then the engine revs high before cutting out
I took off the cowling to see if that made a difference, it ran the same but when I covered the intake the revs settled
so I am guessing its either a blockage or the mixture is wrong.
On here is there anything that explains how to adjust the carb?
I have had it apart and cleaned it but maybe I missed something
thanks in advance
Steve

Did you make sure tank was clean, fuel filter, fuel line etc? Carb may be fine, just not getting fuel delivered fast enough.
Also, which Amal carb do you have?

Hi Michael, yes the tank was cleaned out with Caustic Soda, rinsed out with hot water, dried and filled with the correct mix of new fuel 25/1
as for the filter none are fitted right now, I took off the fuel line and discovered it was just the Banjo, but my order is in with John
I too suspect it's a fuel issue, but I know very little other than reading and asking here I am stuck
its an Amal 416, I have had it apart and cleaned it though to be honest it was spotless inside

There is little to go wrong with these.

Unscrew the main jet prob No. 95.

Hold it upto the light and make sure it is clear.

Then remove the pin and drop the float, this will let you check that fuel is getting past the float valve.

Post some pictures, so we can seewhat the carb is like.
H-A

Check the height on the needle by seeing whereabouts the circlip is fitted. (several different slots)
By having the circlip somewhere in the middle is a fairly standard setting.
With the circlip fitted at the top, weakens the mixture
With the circlip fitted at the bottom richens the mixture

Somewhere in the middle is a good place to start, other than that there's not much that goes wrong with them.
Just keep them clean and that the filters are in place in the banjo and the fuel tap.
Simples.

jon

Thanks H A and Jon, that helps me a lot
I had stopped short of taking off the Brass main jet and yes its a 95
I hadn't seen the slots on the needle but I will check that its in the middle
it is roosting now but after work tomorrow I will do as you suggest and post pics here
That photo helps too, I was wondering if the pin in my float was in the right position and its the same as in this picture

Here are some photos, I checked to see where the needle circlip is fitted and it's in the middle one of 3
it looks like the jet is clear and the float looks right,(to me) I guess once the new fuel pipe, banjo and filter arrive I will give it another try

Forgot to upload this one

Flyguy,

No expert, but the fact that the revs settled after partially covering up the intake suggests it running too lean. From the pics, there looks like a lot of corrosion has been present - did you clean out the carb's fuel inlet from the banjo side and from the carb bowl side (what your fuel needle jet/valve(?) attached to the float settles into)? I'd clean that out well with stiff wire or carefully with a small drill bit - and after, check that the fuel needle jet seats properly.

While you're in there, the brass insert that the main jet screws into - I'd take that out carefully and make sure the airholes near the top are thoroughly cleaned out, too.

The split pin attaching the float could be problematic, too, if it doesn't spin freely and affects the height of the fuel needle jet so that it isn't seating properly.

Just my thoughts on what I'd check for.

If the carb's all good, I'd look for a leak around the crankcase that might be opening up when the motor's coming up to temperature... (Spray around the facing edges & where it mates with the base of the cylinder with soapy water or something like that and check for bubbles)

Good luck with it.

Jason

Thanks Jason, I did wonder about the split pin, it seems like its not sticking, but maybe I should see if I can get hold of a proper one?
will that corrosion contribute to my problem?
I think maybe more cleaning is needed then?

Probably a good idea. The corrosion in the bowl you've cleaned up shouldn't be a problem, but if it's there in the carb's fuel passages, it definitely would be. I'd definitely check the carb's fuel inlet behind the filter screen at the banjo - If you don't have small enough drill bits, maybe a low E or A guitar wire or something like that should do the trick...

I will take it apart again and gently get to work and make sure its totally clean, thanks for the info re. cleaning the jets I have something that I can use to make sure the jets are cleaned without me making anything worse

There is clean then there's Colgate clean
I got an old toothbrush and paste, some of those cheap interdentals for cleaning between teeth, some dental floss to get inside the jets
it surprised me how much oil there was inside, an hour and a half brushing and flossing and its loads cleaner

One thing I don't know, What is the steel stud? on the opposite side from the tickler?
does it come off? does the tiny little hole through it do anything?
pic of the bit I mean below

Air vent into the float chamber.

Thank you Charles, I need to clean that bit too
does it unscrew please
Steve