The single snorkel air cleaner of 036 has a smaller diameter cut out in the base than the later twin snorkel air cleaner. If the smaller AFB carter on 036 was in fact standard, then perhaps the switch to larger chokes coincided with the twin snorkel air cleaner fitment.

The change from 915 casting cylinder heads (high compression), to 906 casting (fairly high compression, open chamber heads) may well of coincided with the switch to the larger bore AFB and twin snorkels... 915 heads and a later larger bore AFB makes for a very nice responsive engine when running on 4 or 5 star petrol!

The differences visible in the above two shots include the electric choke on the new carb, compared to the vacuum operated choke on the older carb. This will necessitate the deformation of the base of the two snorkel air cleaner to clear the new larger electric choke. FF 11 uses an Eidlebrok open air cleaner, which clears the choke mechanism. However, an open cleaner has no fire trap. This is built into the original twin snorkel air cleaners. The fire trap is important on worn or highly tuned engines, which may occasionally backfire through the carb. Because of this, it is essential to ensure that no fuel leaks from the carb, as this can pool in the valley pan, igniting when the engine backfires. Old Holley carbs with a perished diaphram, or other carbs leaking for any reason in conjunction with no fire trap can be the cause of a serious engine bay fire...

The extra butterfly in the '98 AFB can be seen in the lower two chokes. This weighted butterfly can be adjusted by drilling or drilling and filling the weights with lead. No adjustment was required. This extra butterfly makes this aftermarket version of the carb suitable to a wider range of engine and fuel types. The accellerator pump mechanism is also slightly different (top left).

The above photo shows the minor difference at the rear, an extra orifice for emission attachments. On FF 11 this has been blocked up using a piece of rubber.

A small part of the throttle attachment lever needed removed to enable the fittings on FF11 to be used.

A full range of spares is available for the Carter, and rebuild kits retail for about 20 pounds here in the UK. These contains jets, seals, clips and other bits that may be missing from an otherwise good original unit. The vacuum mechanism and linkage is nolonger available, highly prized, and should always be saved if replacing a carb. The bi-metallic choke lever is also not available new. All these rare bits can be saved and swapped at Jensen meetings, or in club magasines... Personally I save the whole old carb!

Once fitted, check for fuel leaks regularly. Air leaks can cause the engine to run lean. Spark plug colour is another good guide... Leaving open an unused vacuum connection (usually at the base of the carb) can be a cause too. All these could result in serious engine damage.