Last time I bought a Volvo Rebuild kit for my carb, it came the Black accelerator pump diaphragm. My carb already had a Green accelerator pump diaphragm, with is suitable for use with Ethanol mix at any percentage. The Black one will break down, so I left the old Green one (might be silicone instead of rubber?) and just used the rest of the kit.
I would suggest buying a marine rebuild kit directly from Holley if possible instead of buying from VP. Make sure diaphragm is rated for Ethanol mix. Even if you don't use E10, you might use it in a pinch. I use E10 all the time without any problems.
Here is a good thread on the accelerator pumps:
http://www.smwebhead.com/phpBB3/viewtopic.php?f=3&t=10033&hilit=rebuildHere is a source for accelerator pumps:
http://www.jegs.com/p/JEGS-Performance-Products/JEGS-Accelerator-Pump-Diaphragms/1391262/10002/-1Note: You can change the accelerator pump without a complete rebuild. However, you might be overdue for a rebuild anyway.
Ray
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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings