Hot start issue might have gone away

[taroz]

Hi all,

For the last year or two my car has been having some of the symptoms of the dreaded hot start issue.

Not had the problem on the initial start with a hot engine. What I got was lumpy running until I managed to get enough cooler fuel into the carbs and then it would be fine.

Normally would take about a minute or so to sort out but annoyingly it once or twice stalled as I started moving and pulled out into traffic… with then an issue of not being able to easily start after the stall!

Anyway, I recently replaced the needles in the carbs and for the last month, over multiple runs, not had any issues with hot start, even in the hottest days so far.

Of course being a classic car owner and obviously highly superstitious, having now written this, I suspect the issue will resurface on my next run!

However, in case this info helps others, thought I would share. If you have tried everything and got nowhere, maybe give changing those needles a try.

Tariq

[jbuckl]

Nice feedback, Which needles though? The main metering jet needles or float valves…. Often also referred to as needle valves too.

[taroz]

Thanks and good question. It was the main metering jet needles, not the needle valves.

The valves I had changed some years back and so far seem to have remained clean and unblocked.

The metering needles as far as I am aware had not ever been changed before. These are the ones that seemed to have made the difference.

[Goldstar]

Thanks and good question. It was the main metering jet needles, not the needle valves.

The valves I had changed some years back and so far seem to have remained clean and unblocked.

The metering needles as far as I am aware had not ever been changed before. These are the ones that seemed to have made the difference.

Good stuff. I’m guessing the old ones were worn and allowing more fuel through than optimum hence the starting issues as you were effectively trying to start a flooded car. Wonder how many others have ditched their strombergs when a simple fix like this might have been the answer?

[gbb483]

I'm guessing you also replaced gaskets etc. What about the insulating block between the manifold and the carbs? Is it possible that that is responsible for the improvement?

[MikeParker]

Thanks and good question. It was the main metering jet needles, not the needle valves.

The valves I had changed some years back and so far seem to have remained clean and unblocked.

The metering needles as far as I am aware had not ever been changed before. These are the ones that seemed to have made the difference.

That is very interesting. I have never had the dreaded hot start issue, despite using the car in high temperatures and often wondered what you chaps were on about. But then I have changed the jets and needles twice in my 100K mile ownership and perhaps that is why the problem has not been present.

Perhaps with worn jets and needles, when the carb boils after stopping, petrol is pushed up through the jet and into the manifold rather that out of the overflow.

I did have my first ever taste of something like the dreaded hot start issue just a couple of weeks back when I parked on the steepest incline I have have ever done, at the Prescott Hill Climb. I was parked nose downhill. I had real problems starting the car and it appeared flooded when it did finally get going. It seemed to me that somehow petrol had flooded into the manifold on that occasion. It has not happened since.

Mike

[taroz]

I'm guessing you also replaced gaskets etc. What about the insulating block between the manifold and the carbs? Is it possible that that is responsible for the improvement?

Only the two metering needles were replaced.

When I managed to recommission this car about 8 years ago, it had been sitting in my garage as a non runner for 20+ years. At that stage I took the carbs off and took them completely to bits, except the metering needles as I didn't feel confident enough tampering with them back then. Everything else was cleaned or replaced then (floats replaced, needle valves changed, everything stripped off, cleaned, lubricated and put back in), the insulating block appeared fine so kept that as was (and still is).

A few years later I had to change the needle valves again as I suspect some grit got into the fuel system and ended up there. Took the time to change some gaskets at that stage too. The only bits I hadn't changed since recommission were the metering needles and so the other month I thought I'd give them a go... turned out pretty easy in the end.

Now I guess it may be that the car has been set to run slightly leaner, can't be fully certain about that, which might be what has made the difference... but the metering needles were the only items that I changed and since then, so far, no issue.