Hard Start problems, Help please

[dreasonover]

I have a 72 chevy truck with a 68 chevy 327 engine, does anyone know what to check for hard starting after it sitting for a week, after the hard start it will start right up until you let it sit again a few days, it has an HEI distributer, elderbrock high rise and a new 600 Elderbrock carb, new plugs and wires

[GMCJOE]

Has it been doing this since it started getting colder? No problems before? Not sure how long you been running this new carb. But I am just going to say, it probably just needs adjusted right.

1. The choke (should be adjusted upon seasonal changes) 2. Fast Idle screw for warm up. 3. Might need to adjust the carb correctly.

If those don't help, check your fuel pressure. Should be 6 psi.

Edelbrock has tech video's for trouble shooting there carb's. Very helpful for someone that doesn't have much experience with carb's.

I would also check your timing. Make sure you have it adjusted correctly. Check for vacuum leaks. I always do this before I start making any adjustments.

[GMCJOE]

It might also just need a few pumps of the gas pedal to put some fuel down into it before you start cranking. It's not fuel injected.

[dreasonover]

I'll do a couple of these checks and let you know if this helps, it seems like the fuel is bleeding off, I have to crank the engine for at least 30-45 seconds while pumping the gas pedal until it starts, I can drive the truck, turn off and restart with no problem until it sits another 3-4 days

[GMCJOE]

Sounds like you could have a defective fuel pump. Bad diaphragm could cause an issue like this.

[cdowns]

after sitting for a week the cheap crap gas evaporates and the dowl needs filling// will b worse if you dont have a phenolic spacer under that carb like edelbrock suggests// so all in all it sounds normal to me

[GMCJOE]

I have the opposite problem he has. Hard to start after the truck sits for about 10-15 minutes. But no problem on cold start up. A lot of research from this problem with the hot starts indicate I need the quarter inch gasket to mate between the carb and spacer. This is relating to the Edelbrock 600 cfm carbs I found the problem with. I run that cheap ethanol fuel myself(not much of an option anymore). Pretty much the fuel is boiling in the fuel bowl and evaporating.

His is the opposite, though it is still very possible that it is evaporating. I am running an electric fuel pump, so fuel is supplied as soon as I turn the ignition on.

I say do the checks to verify everything is kosher. Test that the fuel pump is supplying the fuel right off cranking and check fuel pressure. I would say if you pull the fuel line after it has been sitting for a few day, like when you say you have the starting issue, and check to see if fuel is present in the line. If everything from all the other checks and this comes out good, then I would chalk it up to fuel evaporation problem.

I bought a 650 AVS Street Series Edelbrock, so I am putting the phenolic spacer in with the swap to reduce the heat on the carb. Hopefully that cures the issue I have. I would recommend the same with yours too.

[Square_78]

my truck starts hot perfect and fast everytime. Cold starting it sucks. It has an edelbrock 1406 on it. When its cold I have to pump the gas anywhere from 5-15 times before it will even try to fire. I honestly hate this carburator I have. Im going to rebuild it over the winter.

[GMCJOE]

That's why I bought the 650 Thunder Series AVS Street carb, one I needed the larger carb and two I haven't found anything hot start related with the 650. Though, it seems to be an easy fix with the phenolic spacer and some insulator on the fuel lines.

As cdowns mentioned, probably should put one of those spacers on yours and I recommend insulating the fuel lines also. From a little research I have done, they recommend a 2" for a single plane intake and from a 5/8" to 1 1/2" for a dual plane.

[dreasonover]

Thank you guys, 'll try this and see what happens. The 650 Thunder Series, will it work on a 325 H.P. Engine?

[GMCJOE]

I got a 96 LT1 corvette motor I am going to be running mine on. Which is sitting around 325hp or so right now with the set-up I got going. Should be fine. I am not expert on choosing the right CFM. I normally just run a 650CFM Edelbrock on all my 350's. That was old timer suggestion to me if I was running intake,cam, and headers. Seemed to preform well for me.

Someone got an answer to this question for us?

[dreasonover]

My engine is a 68 Camero 327 with cam and double hump heads with elderbrock highrise, it has the 600 CFM on it now and the carb is new. The truck runs great after the hard start, it starts right up and long as you don't let it sit for a while.

[GMCJOE]

It's crazy we are having the exact opposite problems here. Though, you are running a mechanical pump and I am running electric. Could be the result of the same issue though.

I currently have a spacer on my Bowtie Intake (GM performance intake, made to mate up to the newest production LT1's), but it is aluminum. So, I am sure it is drawing all the heat right up to the carb and boiling the fuel in the bowls after shut down. When I do my LT4 hot cam swap and carb swap, I am putting the phenolic spacer on. Since this will be a while, I am going to watch this thread and see if you get your problem solved.

I recommend googling Edelbrock 1406 hard start. It doesn't reference much about the cold start issue, as it does hot. But like was mentioned above from another member, it could be related to the same issue. Lots of good reading from many forums.

[GMCJOE]

Good luck on solving your issue. I have solved mine already from doing a little research on the LT1 cooling flow. Seems I should have done this a long time ago. LT1's have a reverse flow design, apparently so does the water pump. I routed mine like an old school 350, and I am cooking the carb thru the intake by not getting a good flow going. Hopefully putting a spacer in will correct yours if there are no other issues.