Amal 420

Having problems with a Seagull? - ask an expert here

Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo

User avatar
Charles uk
Posts: 4699
Joined: Wed Feb 27, 2008 4:38 pm
Location: Maidenhead Berks UK

Re: Amal 420

Post by Charles uk » Sun Feb 24, 2019 6:55 pm

416 missing the needle jet & compensator
So your missing the main jet that holds the float bowl on, I don't know what a compensator is?

Help, post a picture.
Make it idiot proof and someone will make a better idiot.

Horsley-Anarak
Posts: 2743
Joined: Thu Aug 07, 2008 8:42 pm
Location: Surrey

Re: Amal 420

Post by Horsley-Anarak » Sun Feb 24, 2019 7:08 pm

fleetingcontact wrote:HA, I have the pump from the 170 and wondered if I could fit it to the 102 cases, other end to the standard tank - stupid idea or not? I'm not at this point keen on doing the remote tank thing. I doubt I'll ever need it.
Yes I have fitted a pump to a century, you need the vacuum from the crankcase to make it work, Kingfisher has a drilled crankcase bolt with a gallery to the crankcase, that is what I did with my century.
2015-06-18 19.19.41.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
fleetingcontact
Posts: 274
Joined: Sat Aug 15, 2015 6:47 pm
Location:

Re: Amal 420

Post by fleetingcontact » Sun Feb 24, 2019 7:45 pm

Charles

Its called a compensator on the Villiers and I'd made a sooooo foolish assumption thats what they're all called. So part numbers 31 & 33. I haven't looked at it in microscopic detail so there may be other bits missing too. I'll take a pic when my camera battery has charged up but its not that interesting - just a smeggy 416...
Amal 416 Diagram.jpg

HA, thanks for that, any chance of a pic with the thing in situ? Did you send the fuel delivery pipe to the gravity tank?
You do not have the required permissions to view the files attached to this post.

Horsley-Anarak
Posts: 2743
Joined: Thu Aug 07, 2008 8:42 pm
Location: Surrey

Re: Amal 420

Post by Horsley-Anarak » Sun Feb 24, 2019 8:07 pm

fleetingcontact wrote:
Did you send the fuel delivery pipe to the gravity tank?
The fuel has just come from there, why would I want to send it back there ?

User avatar
fleetingcontact
Posts: 274
Joined: Sat Aug 15, 2015 6:47 pm
Location:

Re: Amal 420

Post by fleetingcontact » Sun Feb 24, 2019 8:16 pm

Jeez. Did you connect the fuel pump to the standard tank on the Seagull or did you do this so you can have a remote tank?

User avatar
Charles uk
Posts: 4699
Joined: Wed Feb 27, 2008 4:38 pm
Location: Maidenhead Berks UK

Re: Amal 420

Post by Charles uk » Sun Feb 24, 2019 8:48 pm

The choke shroud (compensator) you can live without, I believe John has some on order.
You'll have to use your hand as a choke.

The needle valve is critical, you won't need the pump if you use the 416, what number is stamped on the main jet of the 416 (the bit that the float bowl screws onto.

Which carb needs the needle?
Make it idiot proof and someone will make a better idiot.

Horsley-Anarak
Posts: 2743
Joined: Thu Aug 07, 2008 8:42 pm
Location: Surrey

Re: Amal 420

Post by Horsley-Anarak » Sun Feb 24, 2019 8:51 pm

Jeez ??

The pump feed side of an SU pump, is gravity fed from the tank mounted on the back of the engine, or via an additional connection to a remote tank.

The only reason seagulls have a pump is that the delivery from a cylinder head mounted tank is insufficient for the carb.

If you try and run a 420 without a pump, I have found they run out of fuel as there is not sufficient head to deliver enough fuel.

Remote tanks are generally in a negative head situation, so need a pump.

I am only talking from personal experience that comes from running most of the pumped seagulls including Kingfisher, Seagull 6,170 and successful race engines using 420 carbs .
kingfisher 2.jpg
$(KGrHqFHJCEE9EDFg9wmBP(lJ+FRd!~~60_12.jpg
DSCN5571.JPG
2.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
fleetingcontact
Posts: 274
Joined: Sat Aug 15, 2015 6:47 pm
Location:

Re: Amal 420

Post by fleetingcontact » Sun Feb 24, 2019 9:11 pm

So that looks like a standard QB, don't know for sure since I've never seen one. Is the pumped carb system in pursuit of more bhp, because based on what you just said the QB would be also ok with a 416 and no pump - no?

Horsley-Anarak
Posts: 2743
Joined: Thu Aug 07, 2008 8:42 pm
Location: Surrey

Re: Amal 420

Post by Horsley-Anarak » Sun Feb 24, 2019 9:15 pm

Is this a wind up? Gordon Blair will be turning in his grave.

blokewithaboat
Posts: 66
Joined: Tue May 15, 2018 9:05 pm
Location: uk

Re: Amal 420

Post by blokewithaboat » Sun Feb 24, 2019 9:31 pm

How much of a "bitsa" does fleetingcontact want to make?
Certainly some good advice here from H-A and Charles.

I'm more into the stock variants with very subtle tweaks. My advice would be to opt for the 416 purely because its the closest sized carb to the original 46n 2 jet with pretty much none or very little set-up work left to do. Unless you're going down the route of full on racer with this 102 cylinder then there's very little need to do anything else other than get the engine running to its best potential in the simplest and easiest way possible. Think on the principle of KISS. Keep It Simple Stupid. 416 meets your requirements quite nicely i think. So what if the carb looks manky! It's a "bitsa" after all. It doesn't have to look pristine and besides anything goes. No rules, no judgement, no sniggers behind your back. It's whatever you want to make it, as long as at the end of all this you're happy with the outcome then nothing else matters what we say or think. It's your motor. Get creative.

Best of luck

User avatar
fleetingcontact
Posts: 274
Joined: Sat Aug 15, 2015 6:47 pm
Location:

Re: Amal 420

Post by fleetingcontact » Sun Feb 24, 2019 9:45 pm

No it wasn't a wind-up, and I've never heard of this Blair bloke.

Yup, the main thing is I like it, I've nothing to prove on any of this, it does matter to me (if no-one else) that things look good and not covered in shit and rust and a disgrace on my transom, I don't much care about standard (unless standard is what I'm trying to achieve) and I've heard the KISS thing before. If I wanted simple I would have bought a Mariner.

I would like to hear more about what a full-on race setup for a 102 is, sounds great.

I am stripping the afore-mentioned manky 416 as I write to see what's there and what isn't, I must have given it a bit of a clean a while ago, doesn't seem so bad as I remembered. I'll post a pic in a bit.

Horsley-Anarak
Posts: 2743
Joined: Thu Aug 07, 2008 8:42 pm
Location: Surrey

Re: Amal 420

Post by Horsley-Anarak » Sun Feb 24, 2019 9:59 pm

fleetingcontact wrote: I've never heard of this Blair bloke.
https://www.researchgate.net/scientific ... _G_P_Blair

Seagull QB range are called that because Gordon Blair was a Professor at Queens University Belfast, he was a leader in 2 stroke design among other things.
cdi.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
fleetingcontact
Posts: 274
Joined: Sat Aug 15, 2015 6:47 pm
Location:

Re: Amal 420

Post by fleetingcontact » Sun Feb 24, 2019 10:20 pm

Doesn't really answer the question of why the QB has a fuel pump at all though. I like your 102. Does the swim plate make much of a difference?

I can't see any number on the main jet because its covered in caked-on fuel residue, I've left it in some carb cleaner fluid, I'll have another look tomorrow and its the 416 that is missing the needle. The choke shutter is, I agree, completely irrelevant, and there's a reason why they're in demand, I think.

Horsley-Anarak
Posts: 2743
Joined: Thu Aug 07, 2008 8:42 pm
Location: Surrey

Re: Amal 420

Post by Horsley-Anarak » Sun Feb 24, 2019 10:41 pm

fleetingcontact wrote:Doesn't really answer the question of why the QB has a fuel pump at all though.
Yes It does, how much more explanation do you need? You cant make a 6hp outboard with a Amal 420 carb unless you pump the carb feed, if you put a smaller carb on it it will not produce the power, if it says 6hp on the box it must produce 6hp, smaller carb less power.

Other manufacturers at least 30 years or more prior to the release of the pumped seagulls, were making engines far superior to seagulls, they were generally pumped in the 4 to 6hp range. Seagull were trying to catch up with the rest of the worlds outboard manufacturers. They never managed it that is why they went broke.

User avatar
fleetingcontact
Posts: 274
Joined: Sat Aug 15, 2015 6:47 pm
Location:

Re: Amal 420

Post by fleetingcontact » Sun Feb 24, 2019 11:00 pm

Nope, it was because the opposition's offerings were lighter, cleaner, more reliable and above all cheaper - the same reasons as the rest of the British manufacturing industry. But this is first time in this thread anybody mentioned HP. All I said was the QB would work with a 416 and no pump - but as you so say, with less power.

Post Reply