In case anyone is still looking and stumbles on this thread...
JG Supplies do an own brand replacement on ebay, but if you can get hold of the MerCruiser / Quicksilver part then all the better.
"PRE HEAT RELAY TO FIT MERCRUISER ~ BMW
OEM Part Number: 801334306 Replaced With Our Part Number 420"
Although they don't quote the pre-glow / post glow timings.
Watch out - There are many relays that are plug compatible, but have slightly different timings. The effect of a longer post glow may reduce the life of your glow plugs. Modern plugs (Bosch Duraterm etc) are more resilient to longer post glow times.
Link on ebay at the time of posting is
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=370350134387.
Safest option remains to get the MerCruser part from Eric / Mrs Smillie.
Ta
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