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7/16/12 7:07pm - Original Message: '1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Our '78 pace car has exhibited hard starting (first start) since we've owned it.  Once started, your good to go for repeat starts. 

Pump it several times, attempt start, nothing, repeat multiple times till it eventually fires off. 
 
Our Corvette is driven maybe 750 to 1000 mi per year.  So it spends a lot of time in the garage.  Just to give the most recent history, last Tuesday had hoped to go to local cruise in.  It was very difficult to start.  It had set maybe two weeks.  Finally started and ran fine once started.  Then sat for about four days till yesterday.  NORMAL hard starting and then away you go. 

I don't smell or see gas, but I'm suspicious that the plugs on bottom of carb are leaking fuel out of carb.  Oh, the choke is working and in proper adjustment.

I'm thinking that the carb needs to be rebuilt with a service that will include epoxy covering on the bottom plugs.

I only know mechanical history on work that was done on the car just prior to our purchase.  The receipts do not show any carb work.

Thoughts?  

Experience with companies that offer rebuild service(s)?

Thanks
Gary
Franklin, IN
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7/16/12 7:31pm - Reply: 'Re: 1978 L48 hard start'
KDADDY79
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Dutchess County, NY - USA

Vette(s):
White '79 Corvette. It's a driver.

Joined: 8/27/2007
Posts: 2484
Gary,
Mine is a '79 L-48. From what you described, mine gets similar use.
I had the (Q-Jet) carb. rebuilt a few years ago. The outfit I used was
http://www.thequadshop.net/ . They're located in Rockford, Ill.
One of the other members here at C3VR recommended them to me at the time. I'd definitely give a VERY GOOD recommendation to The Quad Shop.
A few years later and it starts right up like it should and runs great!
If you use this or someone else, let us know.
Kevin


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7/17/12 11:38am - Reply: 'Re: 1978 L48 hard start'
ebo Lifetime Member
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Holland Patent, NY - USA

Vette(s):
#1 *1980 White, Red interior 14,000 mile #2 *1980 Red, Oyster interior 93,000 miles Resto project car, rebuilt to 383 stroker

Joined: 6/3/2008
Posts: 4395
Yep I'd lean toward the Carb also, bad float, acelerator pump, and may be right about leaking. Any signs of fuel around base gasket?
I know my 80 sat forever, the bolts holding down the carb to manifold had loosened to only finger tight.
Had carb redone but mechanic said it was perfect. I had those bottom adjustment screws readjusted after the first 2 years as they were off just a tad.
Good luck let us know how you made out.
Evil Smileebo 


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Evil Smileebo
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7/17/12 2:27pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Thanks guys!  Probably leaning toward a carb rebuild.  Also getting ready to have some exhaust work done.  Hope to get it done before South Central Corvette Club Indiana (SCCCI) show on 8/11 at Hubler Chevrolet in Greenwood, IN.

Right side exhaust sits even with bottom of fender.  Left side sticks down below fender at front of muffler.  So hope to have following done:

.  Both sides even with bottom of fender
.  Exh tips same distance below bottom of bumper
.  Both tips look same from rear
.  Nice mellow tone with new mufflers

Take care friends
Gary
Franklin, IN  

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7/18/12 6:59am - Reply: 'Re: 1978 L48 hard start'
tonytheroofer
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Rochester, NY - USA

Vette(s):
1980 L- 82 fully restored and upgraded.

Joined: 6/12/2012
Posts: 95
Have you checked fuel pressure and fuel filters to make sure they are ok .  

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1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI 
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8/5/12 4:58pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Another sunny/hot and humid afternoon in Southern Indiana.  Garage is quite warm even with floor A/C unit going.

Ok, back to the hard start problem!  Decided to replace the carb inlet fuel filter today.  I really don't know when it was last changed.  Anyway, got the new filter and was in process of putting it back together when I came upon a question - just sitting right there in the carb inlet. 

The carb inlet fitting has a thin gasket on the very end (carb end).  It did not have a gasket on the fitting to body joint just inboard of the hex.  I'm thinking that there should be a thicker gasket there.  I don't have any manuals or books that show that level of detail.

As it is:

fuel line from pump screws into carb inlet fitting - no gasket inboard of large hex - thin gasket at very inboard end of fitting

Am I missing a gasket? 

Oh, on the hard start issue - fired it up a couple nights ago with top of the air cleaner. Pumped it 3 or 4 times - saw choke close with first pump.  Still had to go through multiple pump/start attempts to finally get it going.  Probably cycled through five or six start attempts with maybe 5 pumps per attempt.   Once it starts you are good to go for later starts - like going to a show or the like.  I really don't know when the hard start would come into play, ie. next day, two days later, etc?

Thanks
Gary 

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8/5/12 5:28pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Just went through my bag of catalogs to see if I could learn anything about the inlet fitting.  The only catalog that gave a clue was from ZIP.  They list the following:

68-81      Fuel inlet fitting gasket, red fiber gasket

That sounds like what I'm thinking I'm missing. 

Back to parts store tomorrow.

Take care
Gary


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8/6/12 11:17am - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Fuel inlet fitting on 78 Quad only takes nylon/plastic ring on very inboard end of fitting.  A fiber gasket is not used on the outboard end of the fitting where it screws in against the carb body. 

Only took two stops at parts store(s) with no success , a stop by the Chevy dealer, and finally getting the gasket at NAPA.

Take care
Gary


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8/6/12 12:26pm - Reply: 'Re: 1978 L48 hard start'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19454
I dint see this until now....but now that you got it figured out....LOL

The hard starting issue is most likely the plugs on the bottom of the carb, as you suspect. They will allow the fuel in the bowl to drain over a period of time. I usually take a SMALL hammer, and tap then in a little bit, then epoxy over them. You have to be careful to not get too much epoxy on them, as too much will keep the bottom throttle plate from bolting on flat...then you'll have another problem all together!

The thin "gasket" on the end of the fuel line inlet is just as you described...a small thin nylon ring. They do flatten out, and crack with age. I'm surprised you weren't able to get one at most parts places....I usually see them in the "Help" section. One trick I have learned, if you have a fitting that just won't seal completely, is you can use some thread, and wrap the thread around the threads of the fitting, and screw it in. That usually stops all leakage. Some folks use dental floss, even.


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8/6/12 1:27pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Thanks for the reply.  I have it back together, but haven't tried to start it and check for leaks.

Still thinking that I will have the carb rebuilt shortly.  I've learned of a couple shops in Indy that appear to have good reputation with Quadrajets. 

Take care - Gary 

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8/6/12 7:33pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Hadn't started Vette since last Friday or Saturday evening.  Changed the fuel filter today and attempted start this evening.  Crank, crank, crank. Probably pumped it 30 times or so at least. Choke was closed.  Put a tickle of gas in front barrels - fired up and kept running immediately. 

Also had leak at inlet fitting.  I may apply some teflon tape or string as mentioned above.  Not sure which end is leaking.  At carb or at fuel line.

Job for tomorrow.

Take care
Gary


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8/12/12 7:10pm - Reply: 'Re: 1978 L48 hard start'
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.

Joined: 7/9/2003
Posts: 394
The other place for it to leak at the filter nut is the fuel line flare fitting.  Also be careful when tightening the filter nut as it only engages the first few threads in the carb and they can strip out.  There's an aftermarket filter nut available that goes in deeper and catches some unmolested threads.

There used to be and maybe still is some plugs w/ O-rings to go in place of the ones in the bottom that tend to leak.  They came w/ a piece of foam that kept them from coming out.


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1973 L-82 4 spd

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8/13/12 1:11pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Thanks '73 Shark - Headed out to a local Vette show Saturday after near instant start along with quick spray of carb cleaner. 

Heading over to a friends place tomorrow morning to do some checks on fuel pressure and the likes.

About 100 Vettes at the SCICC club show in Greenwood (IN).  Nice selection of nearly all gens.  Manget 1 and I represented the C3 Registry, but while we both had our Vettes spiffed nicely, didn't get a Top 3 C3 award.

Time to break out the candy dish! 

Take care
Gary


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8/14/12 6:35pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
Back again!  Friend Jeff checked out the fuel pump this morning.  All ok on the numbers. 

The choke was all the way to the lean side.  Moved it two spots richer.  Some concern that choke spring might be losing some tension.

Will check start in the morning - it will have been about 24 hours. 

Take care
Gary


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8/17/12 12:24am - Reply: 'Re: 1978 L48 hard start'
73shark
Standard Member
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.

Joined: 7/9/2003
Posts: 394
When the engine is cold, the choke should close all the way tightly w/ one throttle depression.

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1973 L-82 4 spd

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8/17/12 12:53pm - Reply: 'Re: 1978 L48 hard start'
turbo78vair
Former Member
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Franklin, IN - USA

Vette(s):
1978 pace car replica

Joined: 5/3/2008
Posts: 117
'73 Shark and others!  Tweaked the choke a couple notches richer.  Vette has not run since Wednesday evening.  Pushed pedal down one time - choke closed - I did not get out to see if it was fully closed - Twisted the key, it rolled over and STARTED. 

Guess I'll keep it!  Not that I was considering otherwise. 

Clean up time for tomorrow's show.  Thanks to all for comments and suggestions. 

Take care
Gary


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