Andover Fuel level tool 13.1688

marshg246 · Dec 15, 2020

chaztuna said:
Foam Float Replacement Service Bulletin

Interesting that the service bulletin groups hollow plastic and foam floats as both needing to be replaced..

Also interesting that the Amal "StayUp" floats have been deemed as bad here. Does anyone have any proof that the material used by Amal has any problem? Here's what Amal has to say about it: http://amalcarb.co.uk/new-amal-concentric-stayup-float I have personal proof that the prior plastic floats sometimes fail (only had 3 in 54 years but that's not none). Has anyone here ever had an Amal "StayUP" float fail?

chaztuna · Dec 15, 2020

There is nothing "modern" about direct drive [no gear reduction] piston aircraft engines. The Marvel Schebler carburetors used in them are also used on antique tractors! Almost all Lycoming carbureted engines from 235 to 540 cubic inches use a single barrel, updraft carburetor, of the same basic design. Only the throat size differs. Continental uses the same carbs for their piston aircraft engines.

Marvel Schebler Carb Photos

chaztuna · Dec 15, 2020

marshg246 said:
Interesting that the service bulletin groups hollow plastic and foam floats as both needing to be replaced..

Also interesting that the Amal "StayUp" floats have been deemed as bad here. Does anyone have any proof that the material used by Amal has any problem? Here's what Amal has to say about it: http://amalcarb.co.uk/new-amal-concentric-stayup-float I have personal proof that the prior plastic floats sometimes fail (only had 3 in 54 years but that's not none). Has anyone here ever had an Amal "StayUP" float fail?

Greg,
Mike & I don't trust foam floats, based on past experience/use in auto and aircraft engines. Marvel Schebler tried 3 different iterations of foam floats before giving up on them. Rotax is currently having issues with them. I certainly can not say that Amal's new floats "will" fail. However, history is not on their side.
Les mentions that he knows of no failures in 11 years. Are Amal Mk 1 Concentric Premieres used as OEM on any motorcycles produced in the past 11 years? If not, the number in the field is probably to small to know. Who would you report an issue to?? Does Amal actually offer a warranty on their products? If they do [I do not know], I would assume it would be a 1 year warranty. A float failure in the first year would not be likely, so Amal might not know of failures beyond a warranty period.
As I said earlier, I plan to use Premiers. However, I'm keeping my old plastic floats, just in case. 3 failed plastic floats in 54 years is a pretty good track record. My experience was that any failed plastic float was due to a prior ham handed mechanic, usually the owner.
I earlier asked about the weight of the new floats. I only got one smart alec reply. I asked, as knowing the "as new" weight, would allow an owner to weigh the floats, any time the bowl was off. No weight gain would tell him that all is well. Significant weight gain would indicate that the floats were starting to absorb fuel.