Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,400

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Greg Long
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Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,400

#1 Post by Greg Long » Mon Feb 10, 2020 1:33 pm

I have a new to me 356C. I bought it in Connecticut and drove it across the county to Seattle in October. First time driving a 356! Love it. Ran perfectly except now...

It will only start on Starting Fluid when it's cold out (around 50C) and that still usually takes 3 or 4 good sprays in the air cleaner hole before it'll start, then it will barely idle, but once warm it idles usually at 2,000, but intermittently drops to 1,400. If I set the idle lower it completely dies when cold.

I do the 3 pumps of the gas pedal and hold it half way down before cranking like the manual says but it won't start without ether.

Appreciate your help. Love the little guy and she's a blast to drive when warm!

Greg in Seattle

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#2 Post by jay darlington » Mon Feb 10, 2020 1:49 pm

do you have any idea when it was last tuned up, sounds like it could use one.
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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#3 Post by David Jones » Mon Feb 10, 2020 1:56 pm

I would suspect the distributor. Have you ever lubricated it as well as setting the points? Also look up the starting procedure. On cold days after days of not being run, hold the throttle down to reduce the pumping load on the pistons then once the oil pressure light goes out pump the gas pedal with deliberate 3 second strokes, usual 4 or 5 will do it then when it catches keep it running with judicious use of throttle until it settles down. Idle should be around 850 +/- 100.
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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#4 Post by Greg Long » Mon Feb 10, 2020 2:25 pm

>>>do you have any idea when it was last tuned up, sounds like it could use one.
Jay D. Engine top end was rebuilt by STS in Danbury, CT... a 'serious' vintage Porsche shop. I drove it across the country and around here so maybe 4,000 miles... it had this intermittent high idle problem from when I picked it up in Connecticut.

>>>>I would suspect the distributor. Have you ever lubricated it as well as setting the points? Also look up the starting procedure. On cold days after days of not being run, hold the throttle down to reduce the pumping load on the pistons then once the oil pressure light goes out pump the gas pedal with deliberate 3 second strokes, usual 4 or 5 will do it then when it catches keep it running with judicious use of throttle until it settles down. Idle should be around 850 +/- 100.

OK, will try this for starting; but if I lower the idle it will die immediately after I start it...

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#5 Post by David Jones » Mon Feb 10, 2020 2:37 pm

Greg, that is why I suspect the distributor. If the bob weights are sticking the distributor will not advance until it is warmed up enough that the lack of lubrication is overcome by clearances increasing, but then the bob weights will not move freely and return to their correct position hence the high idle. Get the distributor overhauled and you may find that all will work well again though a tune up is probably an excellent idea. I know there are a bunch of registry members in your neck of the woods so there may be someone around who can loan you a distributor while yours is being restored unless you feel competent to do the job yourself.
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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#6 Post by Wes Bender » Mon Feb 10, 2020 3:36 pm

Please don't continue the use of starting fluid to start it. Search for comments on that if you're unsure about the advice.
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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#7 Post by Geoff Fleming » Mon Feb 10, 2020 3:47 pm

Do not use ether! Most experienced 356 owners will tell you this, as it can be very detrimental to the engine. Since Porsche said nothing about cold starting with such fluids, it is not necessary or they would have advised it.
Do the full tune-up procedure and do so after the distributor has been examined and lubricated. With the engine off, look down the throats of the carbs and you should see two good streams of raw gas injected downward with each full stroke of the carb arm. This raw fuel is essential for the engine to start. There are two injector nozzles per carb. All four should show the fuel injecting into the venturi.
In cold weather, keep the clutch pedal depressed while starting, in order to eliminate the drag of the transmission, with its heavy weight oil.
Modern gas tends to evaporate very quickly in an open system with carbs., so you may consider installing an electric fuel pump as an adjunct to the mechanical pump...it can be most useful as a primer, rather than running down the battery in an effort to create a good fuel flow from the tank. The electric pump can be operated with a momentary switch or wired with a toggle to shut it off once the car starts and the mechanical pump takes over.(Assuming the mechanical pump is in good shape!)

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#8 Post by Tim Berardelli » Mon Feb 10, 2020 6:23 pm

Greg,

What distributer is fitted to your engine-correct unit has cast iron body and will have 022 as last three digits of P/N on an oval data plate. Check your fuel pressure-factory spec. for your fuel pump is 2.9-3.5 psi.

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#9 Post by Doug McDonnell » Mon Feb 10, 2020 10:12 pm

You are getting excellent advice but since you are a Newbie to 356s and your car has Solex carbs being an SC I recommend an electric pump for starting. Since you are in Seattle you have excellent shops who can install one and do a complete tune up and distributor checkup. There is a steep learning curve when first owning a 356. The Porsche Gods were kind to you on your long trip home but your car is telling you it needs some updating/deferred service. 50 degree starts should be easy peasy.
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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#10 Post by Greg Long » Mon Feb 10, 2020 10:30 pm

Thanks folks! The car had a ton of work done by a top shop in the east and this was the Shop's owner's car from new so I don't think there's any deferred service etc; but I will certainly go over everything written here. I'm a DIY guy and that's a big part of the enjoyment of vintage car ownership for me. I'm at the end of a '71 Citroen DS21 restoration so I'm excited to learn about something new... I thought I'd just ask the experts before jumping in. Thanks, Greg

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#11 Post by Harlan Halsey » Tue Feb 11, 2020 5:40 am

356s need to warm up before idling. Mine will idle at 800 after warm up. But will not idle cold. Or if set to idle at 1200 hot then they will idle cold at 800. This is because the manifolds need to warm up. You cannot get a stable idle above 1200 because the distributor advance begins at 1200. If the idle is set above 1200 or even at 1200 the idle speed will hunt up and down as the distributer advance changes. In order to get a nice stable 800 RPM warm idle, the tune up needs to be perfect and the plugs clean and gaped. I use the hand throttle on the As and warmup at 1700 RPM. I close the hand throttle on driving off, and then it idles at 800- till next time.
You are fortunate that there are a lot of 356 people, Emory, Brooks, etc. in the Seattle area. You'll get up the learning curve faster with a little help. The internet only goes so far.

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#12 Post by Mark Sabbann » Tue Feb 11, 2020 8:33 am

Greg Long wrote:
Mon Feb 10, 2020 1:33 pm
...Love the little guy and she's a blast to drive when warm!
The first bi-sexual 356??
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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#13 Post by Martin Benade » Tue Feb 11, 2020 10:54 am

Gender-fluid, it wasn’t having sex.

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#14 Post by Thomas Sottile » Tue Feb 11, 2020 11:35 am

What was the name of the shop?

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Re: Incredibly hard cold start (50F), barely idles, then once warm it idles usually at 2,000, but sometimes drops to 1,4

#15 Post by Robert Vaughan » Tue Feb 11, 2020 5:33 pm

They can be incredibly hard to start if the carb float bowls are empty and the accellerator pump system is empty and you don't have an electric fuel pump or other way of convieniently filling the float bowls. There will be "A whole lot a cranking goin' on!" The idle speed is another separate topic.

You are not alone. Search the talk list for the "fill the float bowls" or "electric fuel pump" or "primer bulb" or "precision matters primer" topics and read.

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