Corvette Forum : DigitalCorvettes.com Corvette Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
371 Posts
Discussion Starter #1
My 79 will start on first turn of the key...for the most part.

If she has been sitting for more than a few weeks, I dribble a little fuel in to the intake and she starts first turn.

Some times, the poor old girl doesnt get started for more than a month at a time. In this time, the fuel sat in the carb probably evaporates.

I thought about fitting an electric pump as this would prime the carb fully before turning the engine and thus eliminating or at least, reducing, cold start wear and tear.

What would be involved and what type of pump would you recommend.
TIA.
 

·
Premium Member
Joined
·
17,444 Posts
Its pretty simple just plumb it in the line and run 12v switched to it.

Remember electric pumps push better than thy pull.
 

·
Registered
Joined
·
3,100 Posts
In that respect, fitting an electric pump to a Corvette is pretty easy- the tank is at the rear (obviously) and the fule lines run up the right side frame rail. Tank fuel pickup is connected to the hard line on the frame with a rubber hose. From all that, it's a perfect place for an electric pump- right rear of the car. Plenty of room as long as you can keep it away from teh exhaust.

Now, the bigger question I have. IF the carb is losing it's "prime", why not chase that problem instead of covering it with an electric pump? There are very few reasons that will happen- bad check valve in the mechanical pump, or maybe the well plugs on the bottom of the carb are seeping. Either of those will be an easier cheaper fix than installing an electric pump.
If you do go with an electric pump, find one that has a maximum pressure of 5-7PSI or be sure and add a regulator. To be a little safer, an oil pressure switch controlling the pump is a good thing too.
 

·
Registered
Joined
·
371 Posts
Discussion Starter #4
Thanks for the replies.

How long would you say the gas in a carb should stay there if after a run, with engine hot, she is put away and then stored for a month?

The only reason I asked about this was because I went to start her this last weekend and I have a plastic syringe I usually keep full of gas to squirt if she has been sitting. The syringe was full when I left it but the gas had obviously evaporated over time.

I turned the car over a few times and it started after a few seconds then stalled. Cranked some more and she fired again I guess as the carb bowls had filled.

I will check the carb as it could probably do with a rebuild but was just looking at other options.
Would the stock mechanical fuel pump be removed and what happens with the return line?
 

·
Registered
Joined
·
3,100 Posts
There are different ways- one suggests leaving the mechanical pump and feeding it with an electric. the other removes the mechanical pump and runs the electric only. removing the mechanical pump, you can use the return line for the regulator, or just cap it off.

I can leave my 69 set for 2 or 3 months- it does take some extended cranking time, and once it starts it takes some time to get it warm enough to run on it's own (no choke), but unless I've had the carb off, and apart, I've never bothered to fill it. I've got a Demon carb on there now, the same was true with the Holley.

Your issue with starting then stalling and restarting really sounds like a typical Chevrolet to me- not exactly right, but real common. YOu could have a problem with the choke settings, choke pull off, or fast idle setting too. A choke pull off misadjusted is probably the most common- many guys dont' understand how it works and then it gets misadjusted and the problems compund.
 

·
Premium Member
Joined
·
17,444 Posts
I agree with Tim on this. On a well tuned SBC ronning a carburator, one should be able to pump the carb nome than 2 times release it and have the engine start and warm up by its self at high idle until it is interuped by the accelorator. It should start like this even if it has been setting for a month.
 

·
Registered
Joined
·
910 Posts
Those were the days before ethanol ;)

Now it lasts no more than a week in the bowl.
Crank for about 15 seconds to fill the bowl, stop, pump a couple times to prime, crank and starts instantly, feather until warm. No choke here either.
 

·
Registered
Joined
·
371 Posts
Discussion Starter #8
Those were the days before ethanol ;)

Now it lasts no more than a week in the bowl.
Crank for about 15 seconds to fill the bowl, stop, pump a couple times to prime, crank and starts instantly, feather until warm. No choke here either.
Its that cranking I want to avoid. Sometimes the poor old girl will sit for a month at a time and all her oil will have drained to the lowest point....Id rather she started straight off and got that oil pumping! lol.

With fuel in the bowl, she will fire and run within seconds.

Not sure what the ethanol content is here in the UK if they even use it......will have to do a bit of googling!


EDIT, OK possibly 5% ethanol at the mo increasing to 5% to 10% by 2013.
 

·
Registered
Joined
·
910 Posts
Probably cheaper and definately much better to install an oil accumulator.
Do some research on the benefits for any engine.
 
1 - 9 of 9 Posts
Top