Best carbed warm start procedure Options

[bbrock]

Apologies if this is addressed somewhere, but couldn't find anything with google search.

I'm wondering if there is a "proper technique" for warm starting a 914/4 with 40 IDFs. To be clear, I'm only interested in what to do with my right foot when starting after the car sat with a hot engine for 15-30 minutes. I'm hoping to megasquirt the engine over the winter so will happily just live with what is a minor annoyance before spending time or money chasing a fuel boiling issue or similar.

Here's some background on my stock 2L with 40IDFs and mild Elgin carb cam. Timing is set at ~32deg BTDC. Fuel pump is relocated to the front 75-76 location. I run a fuel return line, and I have phenolic spacers between the intakes and heads.

I spent a lot of "quality time" with my carbs and a wide band earlier this summer and they are dialed in and running SWEET. I was running the stock dizzy with injector contacts blocked off and the car ran well, fired instantly when hot or cold, and idled steady.

My old dizzy started acting erratic so I swapped it for a new Pertronix SVDA with Ignitor III replacing the points. That is when the warm start issue showed up. Car fires nearly instantaneous on cold starts, but when the engine is fully warmed up and then left to sit 15-30 minutes, I have to crank too long to fire it up again. Seems like holding the accelerator for WOT works best to get it to catch but I haven't played with different combos too much. Once it catches, it coughs back to life and runs a bit rough for about a minute while it spits out the extra gas.

I suppose the E85 might still be boiling in the carb bowls despite the return line and phenolic spacers. If so, I'll just live with it for now, but wonder what folks think is the best throttle position for starting a warm set of carbs. Also open to suggestions for holding my tongue or mouth a certain way if that will help. And for sure a magic combination of swear words would be welcome as I"m a huge fan of those. (IMG:style_emoticons/default/happy11.gif)

[FJ1200]

Two things.

The older Pertronix definitely heat soak and will lose spark, a new ignitor is fairly inexpensive. I have had to dump a 5 gal bucket of water on my distributor twice to cool it down enough to get spark back. Both hot days, long low speed driving and then parked to have lunch.

Second, add a switch to over ride the fuel pump relay. My fathers 190SL will boil the bowls dry in 5 min after a hot run. We added a small Facet pump and tied it into the fan switch (warm weather car no heat required). This refills the float bowls and she fires right up.

And I guess a third thing. Talk a little more about the COP ignition. My plan is similar and I would love to use COP. I have not yet done the homework as to what coils will fit the best. I think it needs to be one that uses a mechanical fastener (bolt) and add threaded standoffs to the tins to support them.

Have a great day!

Dan

[bbrock]

Two things.

The older Pertronix definitely heat soak and will lose spark, a new ignitor is fairly inexpensive. I have had to dump a 5 gal bucket of water on my distributor twice to cool it down enough to get spark back. Both hot days, long low speed driving and then parked to have lunch.

Second, add a switch to over ride the fuel pump relay. My fathers 190SL will boil the bowls dry in 5 min after a hot run. We added a small Facet pump and tied it into the fan switch (warm weather car no heat required). This refills the float bowls and she fires right up.

And I guess a third thing. Talk a little more about the COP ignition. My plan is similar and I would love to use COP. I have not yet done the homework as to what coils will fit the best. I think it needs to be one that uses a mechanical fastener (bolt) and add threaded standoffs to the tins to support them.

Have a great day!

Dan

Thanks Dan. Good info! I've read similar about the older Pertronix. I'm running their newest model that I bought just before they jacked their prices way up. I don't see why it would be any more resistant to heat soak than the older ones though, so still suspicious.

I wondered about letting the pump circulate longer before trying to start the engine. I'm running through the stock relay but without the ECU, the pump runs whenever the key is on regardless of whether the engine is running. I'll try just turning on the key without starting the car for a half minute and see if that helps.

For COP, I'm planning to just buy from The Dub Shop since he has several options that he's already worked out for running on a Type 4. I'm going to go the LS2 route to run full sequential because I have a need to go the most complicated route for questionable benefit. (IMG:style_emoticons/default/lol-2.gif)