Hot Starting Issue

[JSR5150]

Help! I'm having trouble with starting the '72 Ghia when hot. I have to turn the key and floor the accelerator, and it takes 5-7 seconds to fire off.

When I received the car about 6 weeks ago it was down on power, difficult to start when hot, and had flat spots in acceleration. So I adjusted valve clearance, ignition gap, and timing. Power and flat spots improved noticeably, but it still wasn't quite right and continued to be difficult to start when hot. Next I installed a rebuilt German 34PICT-3 Solex from Volkzbitz, which was a huge improvement and eliminated all issues - except for the problem with hot starting.

I've also adjusted the electric choke. Per the instructions, it's closed when the engine is cold and gradually opens as the engine warms up. So I've confirmed that is working properly, and it fires right off when cold. Is there another adjustment to the choke for warm/hot starting? Interested in feedback on hot starting issues.

P.S. - Yes, I know - Relocate that fuel filter! It's going to happen, I just haven't gotten around to it. I've replaced all the fuel lines with new braided hose and I've also used clamps. The plastic temporary filter has hose barbs as well. I'm not sure why all the vendors sell those filters that are flat and have no barbs. Anyway, I have a metal fuel filter I plan to install in the fuel line under the car.

[kingkarmann]

The engine starting procedure is different cold/hot.
Pressing and holding the accelerator to the floor is the correct hot start procedure.

From the 72 owners manual

_________________
"Depression is a malfunction of the instrument we use to determine reality.”

Mike Gerson

What is your "Bespoke Reality"?

[Bugged Again]

Overheating? Run a compression test. My first guess is valves. Does this engine still have the temperature flaps? I’d check that too. Stuck flaps could be an issue but I’m thinking valves. Easy thing to check.

[carlk3]

I have a 1600 SP with a 30PICT-1, so it's different, but I have found through experimentation that it starts best when hot if I just barely put my foot on the gas. Like, just barely cracking the throttle open. No depressing it first, like for a cold start. That way, she usually starts in a split second. If I put too much pressure on the pedal, or something, and it doesn't fire off right away, then I push the pedal to the floor and continue to crank for a few seconds.

When I'm doing something like adjusting the fuel level in the carb bowl and have to repeatedly start the engine, I can usually start it without even touching the throttle -- she'll just start at idle.

[Craigbro]

X2 - I was having issues with this as well. Was trying every conceivable method, driving myself crazy, then...An older VW mechanic from the 60's told me the same thing.
When starting a warm engine, fully depress the accelerator pedal and hold it to start the engine. Magic! works every time

[Trylon]

Had a hard to start when warm problem — the fix was a new condenser. I was surprised as the distributor was new from Volksbltz as well.
_________________
1973 Porsche 914 2.0
1959 Volkswagen Karmann Ghia
1979 Volkswagen Rabbit
1973 Volkswagen Bus
1970 MGB-GT
1962 Oldsmobile Jetfire

More tomfoolery on
The Karmann Ghia Fever YouTube Channel!

[carlk3]

[JSR5150]

[Era Vulgaris]

Have you tried not pressing the gas pedal at all during a hot start? When you press the gas pedal down, you're shooting fuel down the carb throat, which you don't really need when the engine is hot, and might be contributing to the rich fuel smell you mentioned.
Both the 67 and 74 I used to own never needed any gas pedal input on a hot start. Just turn the key and they would fire almost immediately.
_________________
Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD

Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue

[JSR5150]

[Glenn]

[Era Vulgaris]

Have you tested your fuel pressure? Those cheap aftermarket pumps that you have are usually putting out several psi more than you need, and the procedure for adjustment is to stack gaskets under them to lower the pressure until it's correct. If the pressure is too high, it'll push fuel past the needle valve and flood the engine. Might be why you have the fuel smell?
If you haven't done this, you don't actually need a fuel pressure gauge if you don't have one. All you have to do is after a drive when the engine is hot, turn the car off, pull the intake off the carb and look down the throat of the carb. If the fuel pressure is too high, you'll see fuel dripping down the carb throat. Stack gaskets under the fuel pump until the dripping stops when the engine is hot.
Without a gauge it's difficult to diagnose high fuel pressure while driving, because throttle operation will relieve the pressure. But in the minute or two after you shut the car off, that built up pressure has nowhere to go, except to squeeze past the needle valve and down the carb. It'll flood your engine while it's sitting and make hot starts difficult. Once the pressure is relieved to the point where the needle valve can hold it back, the dripping stops. In the time it takes for the car to cool completely that excess fuel has evaporated, which is why your cold starts are easy.

The other easier but more expensive remedy is to buy a rebuilt Pierburg pump, which was OEM for VW, from Sparxwerks and have the correct 3 psi out of the box.
_________________
Currently own:
66 Karmann Ghia, L390 Gulf Blue, under construction, here: www.thesamba.com/vw/forum/viewtopic.php?t=760505&highlight=
99 Mazda MX-5 10AE, Sapphire Blue Mica, 6 speed, LSD

Previously owned:
98 Porsche Boxster, silver, 2.5L -- 67 Karmann Ghia, Black, 1500sp -- 98 BMW Z3, Atlanta Blue Metallic, 2.8L I6 -- 75 Porsche 914, Laguna Blue, 2270cc -- 72 Porsche 914, Signal Orange, 1.7 FI -- 74 Karmann Ghia, Black, 1600dp -- 74 Triumph TR6 with O.D., sapphire blue

[JSR5150]

[JSR5150]

I may have found the solution to the hot starting problem, and it’s not what I would’ve thought. I ordered a new Bosch distributor cap and rotor, which arrived yesterday. The cap that was on the car was kind of generic, and had aluminum points, which I’m not a fan of. So I decided to replace them. Anyway, I replaced those this morning and it apparently has completely eliminated the hot starting issue. I’m still planning to check the fuel pressure, just to be sure. But it appears that a new, quality cap and rotor have eliminated the problem.

Doesn't make sense that this would correct the issue, but I'll roll with it.

[Trylon]