SAAC Forum

The Cars => 1967 Shelby GT350/500 => Topic started by: Brandon on September 12, 2021, 12:00:43 PM

Title: Taking a long time to start
Post by: Brandon on September 12, 2021, 12:00:43 PM
Since I've owned my GT500, if I start my car early in the morning when it's really cold, I'll often have to turn it over for 20 seconds, waiting for the oil pressure to go up on the gauge before it starts.  Next time it starts or when it's warmer the first time I start it, it catches pretty quickly.  The starter never grinds or freewheels, and always engages the engine immediately, just takes time to catch.

Over the past few weeks, it hasn't been cold, and I've noticed that I have to crank it over for at least 10 seconds (again waiting for the pressure to go up) every time I start it.  It always ends up starting, but it's quickly become annoying.

Has anyone else run into this?
Title: Re: Taking a long time to start
Post by: 98SVT - was 06GT on September 12, 2021, 01:24:39 PM
How long is it sitting between starts? The cranking time may just be having to fill the float bowls. New gas with ethanol seems to evaporate quicker than old style gas.
Title: Re: Taking a long time to start
Post by: deathsled on September 12, 2021, 02:03:20 PM
Yes many problems with ethanol. If you ever want to get Jay Leno angry, mention ethanol to him. He will let loose his thoughts about it.
Title: Re: Taking a long time to start
Post by: shelbydoug on September 12, 2021, 02:16:30 PM
Put an electric fuel pump in it in the trunk to prime the carb.

The current pump gas will evaporate out of a Holley or Holleys (I'm running 2x4) in something like 7 to 10 days.

Unfortunately that can also make what is left of it in the carb(s) act like glue on some of the internal parts like the accelerator pump needle AND the inlet needle and seat that the floats close and open.

The saving grace there is that when the inlet valves freeze, it's usually closed. Fresh gas will tend to dissolve that in 20 or 30 seconds but you need to get gas to it and often even need to prime the mechanical fuel pump.

In virtually all of Shelby's race cars the electric pump(s) prime the system and get shut off during the race and let the mechanical pump completely take over even running Webers.
Title: Re: Taking a long time to start
Post by: Brandon on September 12, 2021, 06:06:01 PM
I usually drive it once or twice a week, so regularly sits 3-4 days or more between uses.

These last few weeks where I've been running into it more frequently, as in stopping it for 10 minutes and starting it again, is what had me surprised.  Maybe I got a particularly funky batch of gas or something...

Doug, when you say prime the mechanical fuel pump (versus the carb), I assume you mean via the electric pump.  Do the electric and manual pump work in the same system?
Title: Re: Taking a long time to start
Post by: shelbydoug on September 12, 2021, 07:12:18 PM
Yes they are in the same system. In "Mustangs" electric pumps in the rear trunk work well in conjunction with the front mechanical pump.

I put one in 40 years ago and have never regretted it.
Title: Re: Taking a long time to start
Post by: 98SVT - was 06GT on September 12, 2021, 08:29:20 PM
Quote from: shelbydoug on September 12, 2021, 07:12:18 PMIn "Mustangs" electric pumps in the rear trunk work well

Electric pumps like to push not pull the fuel. Closest to the tank is best. I usually just put them on the frame rail right next to where the fuel line is.
Title: Re: Taking a long time to start
Post by: shelbydoug on September 12, 2021, 09:10:50 PM
Quote from: 98SVT - was 06GT on September 12, 2021, 08:29:20 PM
Quote from: shelbydoug on September 12, 2021, 07:12:18 PMIn "Mustangs" electric pumps in the rear trunk work well

Electric pumps like to push not pull the fuel. Closest to the tank is best. I usually just put them on the frame rail right next to where the fuel line is.

That's not where the R  models put them. They work fine mounted to the left trunk bracket.

The Comp Cobras, the GT40's, the GT350 R-models all put them high in the trunk.

Here's a pick of the R-model. Are you going to make me dig out the other pics?

Mount them wherever you choose. My point is they work fine high and you have access to service them. Why bury them underneath on the chassis?

The Stewart Warner 240 was basically what was available back in the day. That thing is very noisy and almost as loud as a vacuum pump is.

I'm using a Holley and find that it's greatest value is as a system primer. You turn on the ignition, let it run until it stops. It stops when the carb bowls are full, then hit the start.

That saves a lot of needless wear and tear on the starter when the carbs are dry.
Title: Re: Taking a long time to start
Post by: Kent on September 14, 2021, 03:02:56 AM
I would check the timing when its starting, I see it often that a bad timing during the starting procedure has a big affect.
Title: Re: Taking a long time to start
Post by: 428cj6v on September 14, 2021, 08:08:33 AM
Hello, What is your cranking voltage? have you load tested the battery?