I've got a newly built 355 with about 1000 miles on it. It will start up instantly when cold but when starting when hot or after driving for awhile it will take a few seconds of cranking to start and most of the time I have to give it gas to keep it running for the first few seconds. After that it calms down and everything is perfectly fine. It has been this way all 1000 miles. Timing and idle speed are set.

Is this normal for a carbureted engine? Specs are in sig.

Thanks.

 

Somewhat...

Normal in the sense that it happens a lot; but not necessarily "necessary".

Sounds like hot fuel.

Try a 2nd gasket between the fuel pump and the block.

 

Yeah I mean "normal" as in a necessary characteristic of a carbureted engine.

I'm running an external fuel pump that is mounted next to the fuel tank. I do have a fuel pressure regulator that is mounted next to the battery.

Just wanted to make sure it wasn't a symptom of another problem.

 

Shouldn't be a normal thing.
Could be the fuel is getting to hot as sofa said.
Whats the timing set at? And are you sure the carb is set right?

 

Not "timing".

Keep in mind that the boiling point of any substance increase with pressure. With a carb, the fuel bowl is at atmospheric pressure; 0 psi. ALWAYS. Thus, whatever pressure the fuel was under in the lines, it's possible that the temp of the fuel IN THE LINES above its boiling point AT ATMOSPHERIC PRESSURE, but the fuel UNDER PRESSURE remains liquid; BUT, the instant the fuel passes through the needle valve and is no longer under that pressure, if it's NOW above the boiling point, it will flash into foam and spew EVERYWHERE just like that pot of spaghetti noodles on your range top when you get too enthusiastic with the burner.

People coming to carbs who have never had one, but are accustomed to EFI, always want to get worked up about "fuel pressure" and whether they have "enough". Well, that's all well and good; BUT, carbs don't work on the basis of "fuel pressure". All they care, is that the fuel bowl is FULL. VOLUME, not pressure. If the fuel system can keep the fuel bowls full at .00001 psi, then, .00001 psi is ALL YOU NEED. Any more is merely an invitation to problems. (of course, out here in meatspace, it takes more than .00001 psi; might take .01, or maybe even, .1, psi...)

So, first thing you should try is, BACK OFF THE REGULATOR. It's extremely rare that any more than about 5 psi is needed; in fact, the only reason anybody ever needs even THAT much pressure, is that there's a restriction somewhere in the system, and under some conditions or other, the FP will drop below that required to keep the bowls full, if it's not 5 (or whatever) psi under "ideal" conditions (sitting in the driveway idling).

Back off the regulator and see if it helps. Go from there.

 

the float level could be set too high, which lets the extra fuel spill into the intake when the engine is off, which leads to a flooded engine that takes a little bit of time to clear out.. too much fuel pressure will also do this- i don't think an Edelbrock carb likes more than about 5psi before the pressure overrides the float and fills the bowl too far.

also, you say the timing is "set".. but where is it "set"? your motor would probably start and run best with 16-18 degrees of initial timing, with another 18 or so mechanical and 20 or so in the vacuum advance can with it hooked up to full manifold vacuum..

 

vapor lock. carb getting too hot

 

Eddys are notorious for getting hot novaderrick is spot on

You can try a heat shield double check your flot level if you can vent some hot air out of the compartment (half the problem) it may help.

once in awhile my holley will get "hot fuel" and spill over once hot/off not often enough to make me get off my lazy butt and do antyhign more though. Dropping the float level a slight hair helps, long as its notdraining the bowls on WOT seems fine to me.

 

Set the fuel pressure per the carb mfg's specs.


Install a "idle bleed / return line" from the regulator back to the gas tank.
this will eliminate vapor lock by circulating the fuel versus dead heading at the regulator. This is assuming you have a regulator with a return provision.

 

I appreciate all the replies.

As many of you said I do think the problem is hot fuel. When I shut off the engine I want to say I can hear fuel bubbling in the fuel filter/fuel line going to the carb. My regulator is return style and I have it hooked up. My fuel lines are heatshielded where they go past the headers and my line to carb isn't too close to anything hot but I am still using my stock hood...

In any case, I've got bigger fish to fry at the moment so I'll have to tackle this later. Luckily its not too annoying.