Mercedes Benz repair: Timing and air/fuel mixture, head gasket replacement, air fuel mixture

Question
Sir, I've got a 1989 Mercedes 300E and I'd like to know how to correctly set the timing [appears to be a fixed cap], also would like to know how to set the air/fuel mixture.
Thanks for your time, Mick Coyne

Answer
This requires special tools knowledge, and is not an easy DIY.
Read all of these threads.

300E Ignition Timing
http://www.mercedesshop.com/shopforum/showthread.php3?p=283350#post283350

300E rough rough rough idle
http://www.mercedesshop.com/shopforum/showthread.php3?p=183440#post183440

Sharing experience with cylinder head on 103 motor (1986 300e)
http://www.mercedesshop.com/shopforum/showthread.php3?p=249385#post249385

Are yall sitting down? Something POSITIVE about my 300E!
http://www.mercedesshop.com/shopforum/showthread.php3?p=478790#post478790

92 300E 2.6 head gasket replacement.
http://www.mercedesshop.com/shopforum/showthread.php3?p=839388#post839388

2.6 Head Replacement / Timing Chain Data
http://www.mercedesshop.com/shopforum/showthread.php3?p=532113#post532113

Lost timing relation between cam and crank
http://www.mercedesshop.com/shopforum/showthread.php3?p=187536#post187536

300 E with no acceleration - will not rev past 4500 RPM
http://www.mercedesshop.com/shopforum/showthread.php3?p=36256#post36256

Setting initial timing
http://www.mercedesshop.com/shopforum/showthread.php3?p=211296#post211296

Cured my sluggish 300E
http://www.mercedesshop.com/shopforum/showthread.php3?p=876591#post876591

'88 300E ignition timing off. What causes this?
http://www.mercedesshop.com/shopforum/showthread.php3?p=49233#post49233

Stuttering 300E
http://www.mercedesshop.com/shopforum/showthread.php3?p=27304#post27304