amal carburettor
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bruce nickerson
- Posts: 106
- Joined: Mon Feb 04, 2008 9:06 pm
- Location: USA- Boston area
amal carburettor
I have a mongrel Seagull with a "British Silver Seagull" block, Amal carburettor, and a CPC gear case. How can I tell if the Amal carburettor is set up for a 25:1 fuel ratio: I understand it has to do with the size of the needle- how do I identify the needle to tell if it is proper for the 15:1 ratio?
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bruce nickerson
- Posts: 106
- Joined: Mon Feb 04, 2008 9:06 pm
- Location: USA- Boston area
amal on mongrel
Phil: TYVM for guidance.
BUT, I am working with a CPC crankcase, rod and piston, with an ESC block and Amal singgle needle carb. Now what? Perhaps 10:1 to be safe? Wwhat was differeince between ESC and CPC in terms of con rod, bearings, etc?
BUT, I am working with a CPC crankcase, rod and piston, with an ESC block and Amal singgle needle carb. Now what? Perhaps 10:1 to be safe? Wwhat was differeince between ESC and CPC in terms of con rod, bearings, etc?
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bruce nickerson
- Posts: 106
- Joined: Mon Feb 04, 2008 9:06 pm
- Location: USA- Boston area
yet again
Phil: where u from in NS? My father was from Clark's Harbor.
amal carb
The consensus on the site seems to be that a '67 and earlier crankcase limits the mix to 10:1, however, some feel confident in using 15:1 or 16:1 if they use the TCW 3 mix oil instead of the of the older single 30 weight oil. If the carb was off the ESC it is likely the Amal 416 which is factory set for 25:1. If it was off the CPC I think it must be a Villiers carb. Perhaps you could try making up differing petrol to oil in small mixes of 100ml, and try them out in the tank to see how they run.
I'm in central Nova Scotia near Truro, Clark's Harbour about 4 hrs. drive.
I'm in central Nova Scotia near Truro, Clark's Harbour about 4 hrs. drive.
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bruce nickerson
- Posts: 106
- Joined: Mon Feb 04, 2008 9:06 pm
- Location: USA- Boston area
Amal and the Seagull visitors
Phil:
Again TYVM. I expect that 10:1 cannot hurt.
Again TYVM. I expect that 10:1 cannot hurt.
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bruce nickerson
- Posts: 106
- Joined: Mon Feb 04, 2008 9:06 pm
- Location: USA- Boston area
Amal yet again
Phil: The carb was off theESC and is an Amal single needle, so it is a 416. I have a Villiers carb on another block, and they are not interchangeable.
I agree with Phil in that you should run the motor on 10:1 if the crankcase and botton end is pre 67. The problem is whether the carb is jetted for 10:1, if it is not you MIGHT have running problems.
Remember that the oil in the mixture 'condenses' out in the crankcase ( and again in the cylinder ) leaving a set amount of fuel in the fuel air mixture. The more oil in the mixture, the less fuel you have left and so the weaker the mixture. Switching to 25:1 conversly makes the fuel/air mixture richer. Having converted my 40+ to 25:1 it still 4 stroked horribly and I had to screw the needle down a couple of turns.
If the carb is set up for 25:1 as sounds likely from the above it will be set to run a rich mixture, if you try it on 10:1 it will be running weak. Don't have enough experience to tell you if this will cause grief or not but I would personally expect some kind of running problems. As mentioned above, you could try it on a little of each? don't go mad on the 25:1 tho if you have an early bottom end, just enough to see if it runs better and prove you have a 25:1 carb.
Remember that the oil in the mixture 'condenses' out in the crankcase ( and again in the cylinder ) leaving a set amount of fuel in the fuel air mixture. The more oil in the mixture, the less fuel you have left and so the weaker the mixture. Switching to 25:1 conversly makes the fuel/air mixture richer. Having converted my 40+ to 25:1 it still 4 stroked horribly and I had to screw the needle down a couple of turns.
If the carb is set up for 25:1 as sounds likely from the above it will be set to run a rich mixture, if you try it on 10:1 it will be running weak. Don't have enough experience to tell you if this will cause grief or not but I would personally expect some kind of running problems. As mentioned above, you could try it on a little of each? don't go mad on the 25:1 tho if you have an early bottom end, just enough to see if it runs better and prove you have a 25:1 carb.
I agree with Phil in that you should run the motor on 10:1 if the crankcase and botton end is pre 67. The problem is whether the carb is jetted for 10:1, if it is not you MIGHT have running problems.
Remember that the oil in the mixture 'condenses' out in the crankcase ( and again in the cylinder ) leaving a set amount of fuel in the fuel air mixture. The more oil in the mixture, the less fuel you have left and so the weaker the mixture. Switching to 25:1 conversly makes the fuel/air mixture richer. Having converted my 40+ to 25:1 it still 4 stroked horribly and I had to screw the needle down a couple of turns.
If the carb is set up for 25:1 as sounds likely from the above it will be set to run a rich mixture, if you try it on 10:1 it will be running weak. Don't have enough experience to tell you if this will cause grief or not but I would personally expect some kind of running problems. As mentioned above, you could try it on a little of each? don't go mad on the 25:1 tho if you have an early bottom end, just enough to see if it runs better and prove you have a 25:1 carb.
Remember that the oil in the mixture 'condenses' out in the crankcase ( and again in the cylinder ) leaving a set amount of fuel in the fuel air mixture. The more oil in the mixture, the less fuel you have left and so the weaker the mixture. Switching to 25:1 conversly makes the fuel/air mixture richer. Having converted my 40+ to 25:1 it still 4 stroked horribly and I had to screw the needle down a couple of turns.
If the carb is set up for 25:1 as sounds likely from the above it will be set to run a rich mixture, if you try it on 10:1 it will be running weak. Don't have enough experience to tell you if this will cause grief or not but I would personally expect some kind of running problems. As mentioned above, you could try it on a little of each? don't go mad on the 25:1 tho if you have an early bottom end, just enough to see if it runs better and prove you have a 25:1 carb.