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Hot weather starting

Posted: Sun Jun 25, 2017 9:59 pm
by David Morris
Hi All,

I was wondering how other members are finding their cars cope with the recent very hot weather?
Our Javelin ( DCB 246 ) usually has a set routine for starting from cold. It's :- turn on ignition, listen for the electric pump to stop pumping, wait around a minute, full choke and hit the button while 'tickling' the throttle. The result is invariably an immediate start. Don't let her die though, or you will be in trouble. Just let her idle for a minute or two, and she will be ready for the road.

In the recent very hot temperatures ( around 32 degrees C ), I found her totally confused! No choke usually worked, but things were clearly not normal. Of course, this just reinforces my view that our Jowett's have a soul! The return in the last couple of days to our 'normal' temperatures has re-established her usual starting procedure, thank goodness!

How do our members in traditional 'hot' climates find things?

All the best,

David

Re: Hot weather starting

Posted: Mon Jun 26, 2017 10:25 am
by AmilcarJohn
I had an embarrassing moment recently when the Jupiter failed to start after filling up with petrol after a long(ish) run. It started easily after a push from a couple of helpful bystanders and later (once cool) started fine on the button. The car has dell'orto 'Freddy' carburettors with the choke mechanisms removed, which normally doesn't help starting, but choke shouldn't have been part of the equation for a hot start anyway.

Since then I have had a good check and can't find much wrong, other than that the starter motor connections were slightly loose and after tightening it now seems to be spinning the engine a little quicker. I have also cleaned up the battery terminals and put on a new Bosch coil, so hopefully that will help.

John

Re: Hot weather starting

Posted: Mon Jun 26, 2017 3:52 pm
by richard turner
Sounds like vapour lock. My Jupiter used to do it. Hopefully someone may have a solution.
Rich

Re: Hot weather starting

Posted: Tue Jun 27, 2017 9:43 am
by AmilcarJohn
I thought of a vapour lock too, but it couldn't have been in the tank, as I had just opened the cap and filled with fuel. Can a lock occur in only part of the system -between the pump and the carb? The SU pump ticked and stopped as normal.

Re: Hot weather starting

Posted: Tue Jun 27, 2017 3:50 pm
by richard turner
I think th fuel may vapourise close to the carb due to the close proximity of the hot heads and the horizontal configuration. I found the only solution was to go for another pint and drink it slowly! Rich

Re: Hot weather starting

Posted: Tue Jun 27, 2017 8:21 pm
by David Morris
Hi all,

Many thanks for your thoughts. Actually, I earned a reputation which became known in the Section as the 'Morrison's Effect' (They are a UK supermarket chain for those living overseas). I would drive in for a few things and my Javelin would be a pig to restart. She was fine when cold and ok after either a short stop ( like getting petrol ) or a long stop when she had cooled down. But leave her for 15 minutes or so, and trouble would loom!

My immediate thought was vapour lock, as the comments above suggest. I lagged the fuel lines in the engine bay, re-routed pipework and generally tried everything. However, the eventual answer proved to be a dodgy electronic ignition unit. The electronic box was getting warm and when sitting in the car park of Morrison's, the rising heat from the engine beneath proved too much for the electrons!

I downgraded the electronics to a simpler ( and cheaper! ) version and the problem disappeared! At the same time, I fitted a new distributor, as mine was knackered. I purchased a brand new 25D distributor from Accuspark and fitting it was a doddle. They are still available on eBay ( eBay item number 170579588784 ) at £39.95 and free P/P. They are for the 1963 MGB and have a very compatible profile map as ours. Anyway, fitting that and one of their ignition units has been great. Yes, the distributors might be made in a far eastern country, but from new, they are a lot better than my original 60 year old one, with it's knackered bearings.

Hope this helps,

David

Re: Hot weather starting

Posted: Tue Jun 27, 2017 9:14 pm
by Keith Clements
Another possibility is over rich mixture caused by leaking needle valve. Usually a wet carb body or dripping inside throttle are symptoms.