My 528 Hemi is a pain to start if it's cold. It has a Speed Demon on an Indy 426-2 manifold and MSD 6AL ignition. If it's been setting for a while, I have to crank forever to get it to fire, and usually by the time it does fire a couple of plugs will be loaded up and it will run rough for a few minutes. I have an electric fuel pump so the bowls are full when I go to start, and I have a manual choke but I have to pump and pump the pedal to finally get it to fire.

So today I did some checking to make sure I had spark when it was cranking (sure did. Ouch!). The accelerator pump was squirting fuel. No start. So instead of cranking and pumping I poured a little acetone in each of the barrels. Hit the starter and Boom! it fired right up instantly hitting on all cylinders.

I know acetone is one of the things people talk about as a fuel additive but it does little good to put it in the tank because it evaporates so fast. So, I may just have to put some is a squirt gun and go though this routine on cold starts. Better than wearing out the starter. I may try xyol next time since I read of it's use too but the acetone sure worked good this time.

I used to start my high compression 340 with acetone back around 1981. I worked at a place that had plenty of it so I brought some home. Acetone is basically octane booster anyway, internal combustion engines like it, maybe TOO MUCH!

" I worked at a place that had plenty of it "
Meth Lab?

Nope, I worked for Essex Wire and built wiring harnesses for Lincolns and helicopters. I was the wire dye and stripe man, putting the hash marks and stripes on millions of feet of wire! I had to clean the rollers a couple times a day to change colors or patterns. One thing I learned quickly, do not drop the steel rollers in the acetone bath...

You should not have to add acetone or anything else to make it act right. Even tho it bit you when you checked it I'd want a good blue spark & I'd jump from the batt or st relay directly to the coil to get the hottest spark possible to see if that's the issue. Might be bad gas. #1 the choke has to be dead on in cold(er) weather for it to start. Mine (& thousands of others) fires right off in subzero weather if I floor it once to set the choke then I start it. Not sure how much your dual quad intake increases the difficulty since I've never owned one (it's a coming tho)

the question should be "HOW DO I FIX IT?"

WD40 has worked for me in the past.

First, to respond to RR's comment, it has a very hot spark. It jumped at least a half of an inch and was very broad and blue.

The acetone was a test to see if it was a fuel volatility issue, at least in part. I let the electric fuel pump run until there is fuel in the bowls, which I confirmed by observing the squirters. Admittedly the fuel is a little old but it doesn't start great with fresh fuel and my 383 and Rubicon both will sit for while especially this time of year but start fine.

I think it may be a combination of things but the low volatility of modern fuel is the biggest culprit. The Indy 426-2 is a single carb single plain high rise manifold with very large runners. With the carb off you can see the intake valves of the center four cylinders. What I believe is happening is especially with a cold manifold very little of the fuel vaporizes and fuel washes down the runners and fouls the plugs, which hemis are known for. I've tried every combination of choke setting but nothing worked as well as the acetone did. When I lived in the Midwest I used to mix racing fuel in each tank so that probably helped but there is no racing fuel available around here and at 7,000 feet I don't need it anyway. Maybe I'll try some Av gas but I'm sure open to suggestions.

I thought the WD-40, etc aerosol starting solutions were more for the very flammable propane propellant used in the spray cans, rather then the actual contents.

And I never bought into the starting ether "washing " oil off the cylinders idea, unless it was used as maybe, just maybe as a liquid, and not a spray.

I have started my low comp engine with no choke at close to or below zero pump it twice and starts with a point distributor. No fits of cranking You sound as if there is a problem as stated before with ignition. That car should basically fire right up if it was garaged. Don't keep using aids like acetone or ether they will create a problem down the line

On my GTX I turn on the pumps, listen for the bowls to fill, pump the gas 5 times (No chokes) and it fires right up even if its been sitting for several weeks.

No excessive cranking and I only have to feather the gas for about 30 seconds to a minute before it will hold idle speed when its really cold out (been 20-30F here the last few weeks)

Had it out last weekend, lots of fun!

Odd you are having an issue getting it to fire, perhaps not enough pump shot?