1948 V8 ...another engine question
 

Ok, here is what I have.. 48 coupe V8 stock. It had been sitting for years so I am trying to get it going again. I have a new fuel pump, took the Fordbarn's advice and had CharlyNY rebuild my carburetor, put in new points, condenser, crab cap and rotor and distributor bushings and timed it as on the VanPelt web site. Bought new Autolite 216 plugs, new 6 volt battery, new later design 6v coil from VanPelt,changed oil and filter and got it running.
But, its running rough. I figured its running rough because its been stored for so long it needs to run awhile and warm up good. But there is a problem I think. I have a complete new fuel system, new lines(5/16inch) and new tank, but I decided to try to run it from a container at the firewall first to see if I can get it running before filling the tank with gas. I have the fuel pump hose running into a 10 oz jar at the firewall. The problem is that in less than a minute it completely empties the jar of gas.

This is my first flathead and surely they do not use this much gasoline! It might be the over abundance of gas that is making it run rough.

I had cleaned the old plugs before I started it. When I pulled them out they were already coated with dry black carbon, thats when I changed to new plugs but its still idling rough.
It will speed up when you press the accelerator but runs like its missing. I guess I need to give it a compression test next, but it shouldn't suck up that much gas should it?

Re: 1948 V8 ...another engine question
 

Black carbon plugs would indicate it is running rich.

Re: 1948 V8 ...another engine question
 

Here's a question. Because the carb was gone through by Charlie, do you expect it to bolt on and run perfectly? Have you tried to adjust the mixture screws? They don't all run at "one and a half turns out". Try winding each screw in until it either picks and runs better or goes bad again (in too far). If you wind the screws in all the way and it still runs there is probably a secondary reason it is running rich. you can't rule out that some debris has got into the needle valve and is making it flood.

You may have already done all that, but I don't know from here.

Once warm, is it hard to start? Do you have to open the throttle to get it to fire? If so this is an indication it is over rich.

The new fuel pump may be supplying fuel at too high a pressure. That happened to me. I fitted the spring from an old pump into the new pump and it worked ok.

Mart.

Re: 1948 V8 ...another engine question
 

Did you blow out the new lines before attaching to the carb ? Could of bee small brass , steel , rubber in the new lines from install
Which will /could stick float and flood

Re: 1948 V8 ...another engine question
 

No, I did not try adjusting the mixture screws yet. Charlie said the idle speed would probably need adjusting but the mixture screws were set and it ran perfectly on his test engine for three days. So I figured it must be real close.

I did blow out the lines.
I still don't get why it sucks up so much gas. I didn't think the flathead fuel pump was capable of operating at that volume. A fuel pressure regulator may be in its future.

I haven't gotten it to run long enough to warm up because it keeps running out of gas. I thought my old Mason jar would hold enough gas for it to run awhile, but it doesn't. I guess I will need to connect to a bigger fuel supply until I get it worked out.
Thanks for the replies. Still getting familiar with flatheads. Its been many years since I have worked on anything except Chevy v8s with four barrels on them.☺

Re: 1948 V8 ...another engine question
 

If your using that much fuel it sounds as if the carburetor float valve is not shutting off the fuel from the pump. It may have already diluted the engine oil. Check your oil to see if you have fuel in the oil.
Rich

Re: 1948 V8 ...another engine question
 

When Charlie NY rebuilds a carb and test runs it, in my experience it runs great right out of the box. You likely have other things going on like hung valves after sitting.

Re: 1948 V8 ...another engine question
 

Fuel pressure gauge between pump and carb. Too much pressure may be bypassing needle and flooding engine. Check plug wiring and firing order? Good luck. Mike

Re: 1948 V8 ...another engine question
 

'34,
Checking my notes I used your carb to test a bunch of fuel pumps over a few
days. Part of my test procedure is to leave the carb on the motor over night and
in the morning actuate the throttle arm once and with the choke closed I expect the
motor to fire up without any cranking. If that test is successful I'm reasonably sure
there is no leak down and the power valve is healthy. There seems no way the motor
could run for long or at all with that much fuel choking it. Is it possible some fuel is going thru the pump into the crankcase ? I'm envisioning you are in effect gravity feeding the motor. The needle and seat I think are working or you'd be flooding all over.

At any point if you are not happy send the carb back and it will go back on my test motor pronto.
Charlie ny

Re: 1948 V8 ...another engine question
 

I'm no expert but 1948 should be a 59. Vacum line from manifold to front of engine . Please check no leaks. Also are you running a crab style dissy. If so check gasket and tiny little round rubber O ring gasket where the vacmun runs thur into the dissy .
This is just from myself messing around with my junk ...

Re: 1948 V8 ...another engine question
 

It's been mentioned already, but check the oil level before you run the engine again and check of gas in the oil. If it is getting fuel into the crankcase and diluting the oil you can end up with big problems.

Re: 1948 V8 ...another engine question
 

I don't think the needle and seat are the problem either because the engine doesn't flood out, it idles and will crank right back up when I shut it off. It idles but rough. That part might be a valve sticking? I am leaning on thinking the fuel pump is a problem. Tomorrow I will check to see if the fuel is getting into the engine. Its a new fuel pump but you know its hard to buy good parts now. These 94 carbs only need a couple of pounds of pressure, isn't that correct?

Re: 1948 V8 ...another engine question
 

2,1/2 max3 ,

Re: 1948 V8 ...another engine question
 

Apologies to Charlie, I didn't know the carb has been test run. That's good to know.

Mart.

Re: 1948 V8 ...another engine question
 

Sticking valves is a common problem after an old flathead V8 has set for a long time. The float valve in the carb may have some debris that got past filtration during the install or initial run phase so a person can't completely disregard a fuel delivery problem.

New components of an ignition system unfortunately can't always be called serviceable right out of the box. I've had more than my share of bad condensers over the last 20 years or so. Echlin types seem to be better than most.

Re: 1948 V8 ...another engine question
 

If you can hook up a vacuum gage it should be able to indicate valves that are stuck or not sealing if the needle bounces a lot.


Sal

Re: 1948 V8 ...another engine question
 

It may be that it just needed to run for a bit after sitting for so long because I got it to level off and idle smoothly enough so now I am going to hook up the new gas tank and gas lines. My siphon line from my temporary gas jar was a 3/8 hose so perhaps the fuel pump is capable of siphoning more fuel with the larger line. I hope when I connect the 5/16 fuel line that it will be ok.

Re: 1948 V8 ...another engine question
 

Did you check the oil?

Re: 1948 V8 ...another engine question
 

Yes, its appears good, no gas smell or no increase in volume, so I dont think it flooded the crankcase. Speaking of oil, what should be the normal oil pressure for one of these engines in good shape?

Re: 1948 V8 ...another engine question
 

That is going to depend on how the engine was setup clearance wise and where the by-pass is set. On a new engine with tight tolerances maybe around 60# or even 80#. On an older engine it can be a lot less, say 10# to 20# near idle, sometimes lower.

Rumbleseat quote:

OIL PRESSURE: Oil pressure spec for early ‘48 and older engines is 30 psi @
30 mph. For late ‘48 and newer engines it was increased to 57 psi. at 40 mph.
Current performance flathead professional engine builders recommend pressure in
the 80 psi range for hopped up street engines.


I believe some say 10# per 10 mph?