Stromberg hot starting
Posted: Fri Aug 14, 2009 8:22 pm
Ever since I've owned my S4 - over 25yrs now, I've had problems with hot starting. It will start from cold instantly, with a bit of choke in the summer and full choke in the winter. It runs fine, no misfiring, backfiring etc. I get low 30's mpg and tan coloured plugs.
The hard starting has survived the engine in a knackered state and rebuilt - twice and a couple of head rebuilds on top of that. The carbs (Strombergs remember) have been rebuilt twice - new seals, jets etc without affecting it. The float levels are exactly as given in the workshop manual and the diaphrams are new.
I've replaced the fuel pump with an electric one with a pressure regulator and adjusted the pressure from firehose to zero and back to 1psi without improving the hot starting. Plugs are new B6's, timing is 10degrees btdc, points 15thou, plug leads have been carbon, copper core etc over the years without affecting anything other than my tv and the distributor was replaced only a few thousand miles ago (but made no difference)
The characteristics are that the engine will turn over (and over and over...) and occasionally one cylinder will fire - once. This throws the bendix out of mesh and I have to start again. Foot off the throttle or full throttle (or anywhere in between)makes no difference. What does work is leaving it for half an hour - slightly inconvenient if you've just stalled it in traffic. Suggestions as to what to check next gratefully received as I'm starting to run out of ideas.
Stuart
The hard starting has survived the engine in a knackered state and rebuilt - twice and a couple of head rebuilds on top of that. The carbs (Strombergs remember) have been rebuilt twice - new seals, jets etc without affecting it. The float levels are exactly as given in the workshop manual and the diaphrams are new.
I've replaced the fuel pump with an electric one with a pressure regulator and adjusted the pressure from firehose to zero and back to 1psi without improving the hot starting. Plugs are new B6's, timing is 10degrees btdc, points 15thou, plug leads have been carbon, copper core etc over the years without affecting anything other than my tv and the distributor was replaced only a few thousand miles ago (but made no difference)
The characteristics are that the engine will turn over (and over and over...) and occasionally one cylinder will fire - once. This throws the bendix out of mesh and I have to start again. Foot off the throttle or full throttle (or anywhere in between)makes no difference. What does work is leaving it for half an hour - slightly inconvenient if you've just stalled it in traffic. Suggestions as to what to check next gratefully received as I'm starting to run out of ideas.
Stuart