I am having a problem starting my 1976 Chevrolet Shasta Class C after sitting for more than 5 days.

[Stiles Gaffney]

I am having a problem starting my 1976 Chevrolet Shasta Class C after sitting for more than 5 days. I have to remove the center console and air cleaner lid and prime the carburetor with gasoline before I can start it. I had the carb rebuilt and the fuel system checked out along with a tune-up. The 350 engine runs great once you get it started. The engine fires up right away if it is only been 1 to 4 days of being idle. I can not figure this one out. Any suggestions? Thanks.

[Russell E Johnson]

What is happening is that the gas is evaporating from the carb. and the fuel filter. Since you probably do not have an electric fuel pump it takes the mechanical pump a looooong time to get gas back to the carb. Electric pumps are not expensive anymore ($50-$100) so I would install one near the fuel tank, with an inline filter prior to the pump, and wire it up so when the ignition key is turned to the on position the pump will run. On my Southwind I turn the key on for a few seconds to allow the fuel to pump back up to the carb (it is also a Chevy chassis) and then start it. This should cure your having to prime the carb to get it started. Also, there is no reason to remove or bypass the mechanical pump, the fuel will pass right through it (cravat: it has worked on the install I did and a dozen or so others that I have heard of being done back in the days before electric fuel pumps).

[Stiles Gaffney]

Thanks Russ,

I will try that.

Stiles Gaffney

[John "T" Nordhoff]

  BTDT and got the T Shirt also. To my way of thinking unless a carb has some leak problems the bowl ought to hold gas at least a few days before it evaporates, but temperature and humidity may enter the equation, so maybe after 5 days its simply evaporates and there's nothing else wrong whatsoever. IE it just goes with the territory.

 With all due respect to my friend Russ I have a different take on installing after market elec fuel pumps on mechanical fuel pump engines BUT IT WOULD BE A BORING WORLD IF WE ALL HAD THE SAME OPINIONS LOL. When I installed an elec pump I always removed and blocked off the side oblong hole where the old pump was. The REASON was I feared (maybe justified maybe not ????) if the old mech fuel pump sprang a rubber diaphram leak the elec pump would quickly fill the crankcase with gas and I don't like the sound of that.

 SURE I know guys have left the mech pumps and never had a problem but I heard horror stories  of an elec fuel pump filling the crankcase if the old pump leaked. Or maybe its just an old wifes tale ??????

 Like Russ I would install the elec pump back at the tank as its easier to push then suck fuel all the way up front.

ONE MORE FEAR I HAD On modern cars equipped with elec fuel pumps theres a crash or tumbler switch in series with power to the pump so that a sudden shock or stop or severe jolt (a crash) trips the switch and power is cut off to the pump so it dont keep pumping gas onto a burning engine or elsewhere if theres a crash. BUT IF YOU INSTALL AN ELEC PUMP AND NOT THE SAFETY CRASH SWITCH TO ME THATS A HAZARD???  

 

 Don't get me wrong, I prefer an elec pump but want the safety feature a crash switch (like elec pump cars used standard equipment) affords and don't want to take a chance gas could fill the crankcase if the old mech pump sprang a leak.

 Just another opinion nothing more, do as you like. Ive been wrong before ya know lol and will be again..........

 God Bless all and Happy Fourth of July

 John T

[Russell E Johnson]

Good point, I forgot about the possibility of the diaphragm leaking. So yes, remove the mechanical pump and seal the hole. Also the crash/safety switch is necessary addition. Thanks John T for pointing that out. Another serious omission on my part. Glad there are others out there to keep track of me and my feeble brain.

[John "T" Nordhoff]

 Mornin Russ, I wouldn't say you're feeble in the MIND but I cant testify about your body lol. Hey I've seen guys put elec pumps on and leave the mechanical and sure it works but in my old age I'm just getting safety minded so the safety tumbler crash switch and the thought of a leaky diaphram makes me squirm lol Just because I do things one way don't make them right for others but as long as it does for me that's what matters right.

 Best wishes and God Bless yall

 John T

[Stiles Gaffney]

Thanks John,

Happy 4th. I will check out the cost for all of this. Summit racing has a Holley fuel pump for $47 so this should be relatively cheap depending on labor.

Stiles Gaffney

[Jack Wasmuth]

I can bet my life on the evaporative nature of our gas with the alcohol in it. I have over 40 years experience with rebuilding carburetors and dealing with fuel injection and I agree with the others that it is evaporating.

[Jimco_W001]

There are four general types of GM fuel filters that fit these carburetors. Short or long and with or with out a rubber check valve at the front of the fuel filter. This check valve missing or leaking could be your problem.

[Stiles Gaffney]

Thank you Jim,

I will check this out. I am going to go with an electric fuel pump while eliminating the mechanical.

Stiles Gaffney