Engine's got me stumped?- No Power

Special Coupe Frank said:
If your issue is not enough fuel supply, pulling the choke probably won't help or will only help momentarily, as there's already not enough fuel in the carb.
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Momentarily may be all that's needed.

Pulling the choke will often force whatever fuel is available to speed the engine up just long enough to let the driver know that the lack of fuel, already suspected, may be the problem.

Although a dangerous move for some, pouring in a trickle amount of fuel while increasingly opening the throttle as I suggested in my post above will most certainly speed the engine up if lack of fuel is the problem.
 
Tiiiiiiiiiiiiiiiiiiiiiiiiiiiiiim!!

I just went through this on my Model A...

I had swapped a 97 on it and it sputtered and popped.... ran like dog dookie.

I figured it was the carb... so I found a glass bowl Holley like my dad used to run.

Put it on with a header... ran and sputtered...

So I looked at the jet and it wass a 66...

Put a 72 in it, ran great around town.

So then I decided to take it out on the highway.

I took it out Stanley... long road here in Livermore... and ran her up.

The thing sputtered and popped at about 45-50mph.

I ran it up where it was sputtering and popping and **** the fuel and ignition off at the same time.

I pulled to the side of the road and looked at the fuel level through the glass bowl...

Sure as snot... the bowl had about 1/4" of fuel in it. Not enough.

So I bought a fuel pump... and regulator.

I installed them and just for grins... set the pressure at 1 pound.

I revved it up in the garage... and at 1 pound... the fuel level gradually went down.

Crazy thing also happened...

The fuel was buzzing and bubbling at the top of all the fuel in the bowl due to all the vibration. So if the fuel level isn't where it should be... you can get an inconsistant supply to the main jet.

Next up... crank the regulator up.

As I gradually turned up the pressure... with engine revving... I saw the fuel level slowly rise. It was where it should be when the regulator was at 4psi.

The thing ran so good we decided to take it to Modesto for dinner at my mom's... and proceeded to lose a rod bearing about 45 minutes into the trip! Damn!

Might not be able to get that much on the seat of a 97...

Anyway... I think I'd see where it was jetted and add an electric pump if you haven't already done so.

When are we gonna go on tour?

Sam
 
We should go on tour Sam! Thanks for the advice on the fuel pressure and the Jet. I'll go find a 72 and see what happens. Sorry about your rod bearing, good thing you still have that spare. This car definantly has a personality all its own. I've dumped all the old gas out and am now going from zero, using all the suggestions above starting with fresh gas.

What gears are you running in the Coupe?


Tim
 
A long shot for sure, but how is your voltage to the coil when running. You might have a bad amp meter or terminal box connection.
 
George Miller said:
A long shot for sure, but how is your voltage to the coil when running. You might have a bad amp meter or terminal box connection.
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That ain't no lie. That's why Tom W. suggested putting a load on the ignition by making the spark jump long distance.

Changing the subject ....

Have you had a chance to try out your self-made head?
 
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I had the same problem with a 31 Tudor and a new 97 carb. After trying all the fixes suggested here, Iput on a rotary fuel pump. I had good gravity gas flow and thought that was plenty, but with the fuel pump installed, I had no more problems.
 
Tim said:
We should go on tour Sam! Thanks for the advice on the fuel pressure and the Jet. I'll go find a 72 and see what happens. Sorry about your rod bearing, good thing you still have that spare. This car definantly has a personality all its own. I've dumped all the old gas out and am now going from zero, using all the suggestions above starting with fresh gas.

What gears are you running in the Coupe?


Tim
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Tim,
Study Sam's input carefully. In my opinion/experience...he has a valid position. This MAY seem overly simple, when considering others, but my perfect running four banger(with two downdraft 81s/elect ign,etc) poped/stoped when I took the fuel pump/regulator off of it AND RAN IT(GRAVITY) WITH 1/3 TANK OF FUEL!! Yes, it runs GREAT with a full tank down to 1/3 tank. I intend to reinstall pump/regulator, as otherwise it's manditory to maintain it gassed up. If I were in your position, I'd take a good gas container, fill with fresh gas, place it above the carb height and connect it independantly to carb gas line. This would be an inexpensive test. You say that you 'had 1/3 tank and I say...that without pump, that is NOT enough. "Try all the simple stuff first", before changing/spending! Rick
 
Larry Brumfield said:
That ain't no lie. That's why Tom W. suggested putting a load on the ignition by making the spark jump long distance.

Changing the subject ....

Have you had a chance to try out your self-made head?
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Hi Larry yes I have. It is running very good, my plan is to take it to the hill climb in April. It pulls very strong at about 3000 rpms and up
 
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Be sure that your gas cap is vented properly.....run the car with the cap off and see if it makes any difference. Many of the repo caps have to be screwed in place for them to vent.
 
Tim... the single 72 jet is a Holley jet... and the 1904 carb only takes one where your 97 takes two.

I couldn't tell you what size you should step up to, or even if you should.

I would try the fuel pump first... then try jetting the carb.

Sam
 
Good news today,

pulled the exhaust pipe off and engine ran the same. Not a plugged muffler, checked off the list. While I was in a dissasembling mood I pulled the intake,header and side cover off. No busted valve springs. I will adjust them while I'm in there. Movin on to a fuel pump with high hopes. I'll report back. It should only take a few days and I'll know.

Thanks again,

Tim
 
pat in Santa Cruz said:
any sign of a warped intake or blown intake gasket?
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Pat, I was going to call you tomorrow as I didn't want to bug you on a Sunday. No signs of warped intake/exhaust gasket. The manifold appeared square as well. But I didn't use a straightedge yet. I'll put it to the marble slab and see. Are you around tomorrow?


Thanks again,
Tim
 
You mention possible blown carb power valve but dont say if you checked it. Also, modern Holley power valves do not seat well in the old carbs. Put them in, fill the bowl and they will leak out slowly but surely. Had a hard time with power valves on my Holley 92's. There are web sites on the problem. Jere Jobe overhauls the Holleys and Strombergs and does great work.
 
Ken CT who is usually on thr EV8 side of the Barn and wwho posts here occasionally is also into the repair of carbs. Excellent reputation, so they say.
Paul in CT
 
Today the engine revealed its weakness to me.

At idle it's perfectly happy, compression on all cylinders is good, ignition is putting out a long blue poppy spark on all the dizzy points, carb is working like it should, put in a fuel pump set it at 1.5 then 2 lbs still having same issue.

I pull the top of the carb off and make sure the float level is right on the money and it does exactly what it's supposed to do with 2lbs of pressure.

The intake is cold from the venturi affect but no ice or crazy stuff like that.

Then it pops into the carb, aha now we're getting somewhere. I get it to rev up and I'll be dammed if it doesn't start pushing fuel up through the top of the carb into a cloud at the throat and slightly above the carb. You can only see this with a flashlight aimed across the top of the carb. It pops again and the fuel cloud is more noticeable.

All this leads me to believe it's an intake valve not sealing due to carbon, burned, or a busted spring. It's doing just fine at idle or under no load and shutting but when it's asked to slam shut under a little RPM no dice.

So I thank all the people who made suggestions and helped me out. But after all the changing and checking it's a physical problem and the engine has to come out for some R&R. The bottom end is good so that's a relief. I did have a chance to see the inside a little better and was pleased with the standard bore, original timing gear, and camshaft. The intake/exhaust surface is perfectly flat. There's alot of good stuff still in the engine it just needs a valve job. While I am at it I'll put in my Touring cam and adjustables. It was time I guess.

I would like to especially thank Pat in Santa Cruz for helping me and offering to come over.


Tim
 
Tim - Why not just pull the head and grind the valves? I did it on the flat-4 in my forklift. Couple of hour job...all better now.

Neal
 
Tim, Mart here.
A friend once had a similar popping problem in a sbc.
He had a bad cam lobe, on the exhaust, I think. The bad cylinder would blow back out through the carb, upsetting all the others. Can you see if all the valves are lifting an appropriate amount??
Mart.
 
Mart, I'm going to check the lift. I have a B Cam to put in if the A cam is bad. I spoke with Pat in SC last night and he suggested the same thing Neal did. Instead of making a mountain out of a molehill I'll grind the valves in block first and see what happens. Pat also said it could be the new Ethanol gas separating and leaving a heavy varnish on the stems making it stick. But either way it's not running and it's a bummer.


Tim
 
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