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Hi gang. Beautiful day here on the Delmarva Peninsula.
Went to a small cruise in last night and developed a fuel issue on the way home. I'll give you the rundown.
Cruise in was about 14 miles away. On the way there , Truck just did not seem to have that much power. Took a lot to get it up to speed. There was no increase in RPM's if I put accelerator to the floor. Was at the event for about two hours.On the way home, truck lost all power. Engine ran, but could not accelerate. Changed fuel filter. See thru filter would not fill up. Limped home. This morning, truck started right up, fuel filter full. Ran for about half hour. Fuel filter not filling up.
Background. New gas tank, new fuel lines. Rebuilt fuel pump.
!. Am I chasing a vapor lock?
2. Am I chasing something floating around in the new tank.
3. Am I chasing some sort of a fuel pump problem.
Truck is idling great. RPM's not consistent when Accelerator is pushed.
Trying to chase a problem when it isn't occurring is always a pita. Depending on how long it ran before the problem showed up it could be vapor lock - you need heat build-up to cause gas to boil before the pump, causing it to suck air instead of fuel. If it happened before that should have been an issue you probably have a sticking inlet or outlet valve in the pump. A stretched or perforated pump diaphragm normally doesn't create intermittent issues. Nor do vacuum side (between the pump and tank) leaks that would cause the pump to suck air instead of fuel. With so much ethanol in fuel these days the rubber parts of the fuel system don't last as long as they did years ago. Look for quality parts, hopefully labeled "ethanol resistant' or such.
CBeav, Forty Niner. Ross,
Thanks for the assist. Here is an update. Tested out flow of pump. Filled about 12os in 17 sec. So that function seems ok. How ever, when line is hooked up to carb, fuel filter will not fill.. Truck will idle great, Not much happens when you step on gas sometimes. What I'm thinking now is the Carb must be stuck, maybe the float or something, preventing the fuel from getting in to Carb. This is a 2 bbl, I believe TeaPot. What is the most logical way to proceed. This carb was professionally rebuilt in 2010. Since then, used during restoration and there is only about 200 miles on it since rebuild. Maybe some gunk or stuff gummed up.
Thanks for any assist.,
First thing I would do is tap the carburetor with a plastic or wooden screwdriver handle in the area of the fuel inlet. Picture of the carburetor may help. When you fee flow tested the pump, did it seem to have any pressure or just drip fuel? You should see a definite discharge away from the pump, line or hose.
Edit: Just remember seeing this a while back, FWIW.
TESTING THE FUEL PUMP
Fuel pumps should always be tested on the truck. The larger line between the pump and tank is the suction side of the system and the smaller line, between the pump and carburetor is the pressure side. A leak in the pressure side would be apparent because of dripping fuel. A leak in the suction side is usually only apparent because of a reduced volume of fuel delivered to the pressure side.
Tighten any loose line connections and look for any kinks or restrictions.
Disconnect the fuel line at the carburetor. Disconnect the distributor-to-coil primary wire. Place a container at the end of the fuel line and crank the engine a few revolutions.
If little or no fuel flows from the line, either the fuel pump is inoperative or the line is plugged. Blow through the lines with compressed air and try the test again. Reconnect the line.
If fuel flows in good volume, check the fuel pump pressure to be sure.
Attach a pressure gauge to pressure side of the fuel line. On trucks equipped with a vapor return system, squeeze off the return hose.
Run the engine at idle and note the reading on the gauge. Stop the engine and compare the reading with the following:
6-cylinder inline engines.....4.5 to 6 psi.
V8 engines.....5 to 9 psi.
If the pump is operating properly, the pressure will be as specified and will be constant at idle speed. If pressure varies sporadically or is too high or low, the pump should be replaced.
Remove the pressure gauge.
The following flow test can also be performed.
Disconnect fuel line from carburetor. Run fuel line into a suitable measuring container.
Run the engine at idle until there is one pint of fuel in the container. One pint should be pumped in 30 seconds or less.
If flow is below minimum, check for a restriction in the line.
Ray, appreciate the help. Re-tested fuel pump. Out ward pressure is 6 lbs.
Volume id 12 oz in approx 16 sec. Checked draw from fuel tank and also spar gallon container.
All lines appear to be free and clear.
I will try the tap portion of the test probably tomorrow. Getting hot and humid today.
Carb ID Holly EAL-9510 M List 893
The item at bottom of seat for air cleaner is a Holly Governor.
The item below the base of the actual carb is an additional governor controlled from pump panel( this unit is disconnected and serves no function. other the to mount the carb. This unit is on a fire truck, 279 Lincoln engine. 1954
Thanks for your help and sugestions.
Ross, I have an electrical pump as an emergency back up. It is not currently hooked up, but test at 6-7 lbs. It is my understanding that they have to be mounted close to the tank, that they are good pushers as opposed to pulling fuel like a regular pump.
First of that type carb with the governor incorporated that I've seen. That appears to be the type governor that has a valving mechanism that restricts flow. Has that valve been removed or disabled? Any chance the the valve could be closed?
Edit: You are right, electric pumps are good pushers. So long as you have gravity flow to the pump, they will work fine.
Ray, I assume you are talking about the built in gov. on the carb itself. It is a Holly 1901 FFG, installed on the bigger trucks that year. I am not sure how it works, but it was also rebuilt when they did the carb. I have been looking for articles on how it works. There may be a article in my shop manual. I have to go out to the shop and get it.
Just before, I reassembled all the gas lines and ran the engine again while tapping on the carb itself. It will get up to about 900-1000 RPM , but waver, Nothing past that. I'll start reading. Thanks for you assist.
I suspect that governor works like a variable restrictor plate. I would imagine the process was to set it while running the pump under load and the governor would kick in so as to limit engine speed when the pump ran dry. Make sure it is not stuck in the closed position.
Do you have a control to set engine speed for the pump? Does that tie wrap hold that cable in a solid position against the mount bracket. Perhaps that is your governor set control?
Edit: I looked at that tie wrap again. So long as the cable end near the carb is solid, you should be good.
Craziest looking governor I've ever seen. Wondering if it's actually two governors - one for engine speed and the other for fire pump pressure or PTO speed.
