Hey guys, I'm messing with a Y block for the first time. Trying to get it fired up, but I have no fuel getting to the carb. The vehicle is a '64 F100 with what I believe to be the factory 292 Y block. I put new fuel in the tank, and removed the sender so I could make sure everything looked ok inside the tank. After cranking and getting it to fire up for a moment with starting fluid or pouring gas down the carb, I removed the line to the carb, and it was bone dry. I removed the feed line to the pump, and it was dry too. So, I siphoned gas out of that line so I knew I had fuel at the inlet side of the pump. Still bone dry on the other side. So, I thought the pump was bad, even though it was a newer pump put on by the previous owner. It did look like a cheap pump. I replaced the pump with a Carter M3528 pump. No change. The fuel line to the pump is not plugged, and there is no pre-filter. There is a new hose and filter after the pump. Any thoughts? Is it possible that the fuel pump eccentric is worn enough to not pump? I cranked it over with my finger over the end of the hose coming out of the pump. It felt like it was trying to do a little bit of something. It kind of seemed like it was too easy to bolt the pump on. Usually when something goes that smoothly for me, it's an indication that something is wrong. Haha. There is an old electric fuel pump still bolted to the frame, this could be an indication of something wrong, or simply an electric pump was installed. I plan to stick a flexible camera in there to see if I can see anything. If there is something else I should check, I'd like to hear about it.
Oh, I have seen this on a couple of engines that are set up like a Y-Block. Pull out the fuel pump and see if you can see the fuel pump eccentric. Unlike some engine where it is a permanent part of the cam, on the Y-Block (and others), it is a separate component: I have found them missing, always for reasons that I cannot explain. It still might not be the problem, but it is a good place to look. It is about as thick as a heavy washer where it bolts down. It is entirely possible that it is not there.
From all you have described, the eccentric seems to be the problem. You should be able to crank the engine with the pump removed, and see the eccentric with the mirror/flashlight trick. An installed electric fuel pump shows an indication of previous trouble.
Thanks guys. I’m going to try to take a peek at it tonight after work. If I see anything weird, I’ll probably grab an extra electric pump from the shop to see if I can keep it running.
Hey guys, So after I got home, I pulled the pump and looked in there with a mirror and the flexible camera. The eccentric is there. I got a friend to crank it over for me and it looks like it’s doing what it’s supposed to. What else could it be? Is there different size eccentrics for different years and mine could have gotten swapped with the wrong one or something? I know I could put in an electric pump and be done, but I now presumably have 2 new good mechanical pumps, so it would be nice if those worked.
There are a whole mess of bolt on eccentrics. I am unsure if there is one that would interchange, or just happen to fit.
I'd be inclined maybe to see if the pump itself works, if there is some question about the camshaft pump eccentric. Feed the inlet to the pump with gravity fed fuel from a boat tank or maybe connect a vacuum gauge. If the pump arm is doing its thing, it should work, it might then be a matter of finding air leaks or pinholes in the line or hoses, something like that. Did you replace that short section of hose underneath the cab? There are a lot of places where the fuel line can have leaks or pinholes, including inside the tank. Depending on where the cam ends up on shutdown it can sometimes be tougher to install the fuel pump and get the bolts started, if you haven't ate yer Wheaties. Bump over the engine over slightly to move the eccentric, so you're not fighting against the pump arm tension.
Check the rubber fuel lines...sometimes there are multiple sections. One of those having a crack/split on the top or something will do pretty much what you are describing.
All the rubber lines are new. I'm not the one who installed them, but they have been replaced. The short section under the cab, then another short piece to the inlet to the pump, then its rubber all the way from the outlet of the pump to the carb with a filter inline. I did siphon the gas down to the inlet on the pump to make sure fuel was getting there. I have not yet tried gravity feeding from a different vessel, but I can give that a shot. The Carter pump did seem to be doing its thing when I just actuated it by hand. That's why I was thinking about the possibility of there being a smaller diameter eccentric from a different year Y block that could have gotten swapped in or something, and maybe the lever simply isn't being moved far enough. I'll give all the lines an inspection, and try using fuel from a different vessel.
I'd check the clamps on those lines and have a look yourself. I've even had it happen that I had a good rubber line, but it had the factory spring clamp still...and it was sucking air there. I guess it wasn't a good seal on the metal line.. I put a regular screw style clamp and it fixed it.
Pull the pipe off the outlet side of the pump and hit the starter. If the pump is working it'll splash a bit of fuel around but that'll evaporate (I have no idea were a pump is on a Y block so can't comment on volatility of splashed fuel). If not pumping your pump is cactus. Just imagine having to do this on a wet winter night out in the boonies. Rather do it in comfort of the shop.
I would double check the tank again. On a 1964 F100 the fuel has to be drawn up to the fuel sender. The feed line and gauge assembly are one unit. It's seems like that is it. I'm too lazy to go look but anyway, the fuel line exits the top of the tank. The pump has to pull fuel up to the top of the tank. I would take a look here. You may be sucking air somewhere or have "bad gas goo"...(it looks like tar) partially blocking/stopping up the line in the tank. Make sure the seal for the sender is good.
While there are two different eccentric set ups for the Y block they are interchangable. the only difference is that the newer style does not use the counterweight. both eccentrics are the same dia. and will stroke the pump.
In 1966 I had a 292 in my first car and someone had put a washer under the bolt that held the eccentric on the cam. It made the bolt head rub against the timing cover. Eventually the bolt loosened enough the eccentric could spin. Unfortunately for me I did not see the witness marks on the cover the first time it happened and had the bad fortune to get to do it again.
Hook up that electric pump. If it won't pull any gas either, I'd guess the problem is in the tank pickup. Maybe it's clogged inside where you couldn't see. Maybe the tank isn't venting properly?
Disconnect the line coming from the tank. Use a gallon gas can and rubber hose as a temporary feed. Crank it and see what happens. Just because you are able to siphon fuel through the original line doesn't mean it's not clogged. I just went through the same thing on my Plymouth. I could get fuel to pull through with my mityvac but my new fuel pump wouldn't pump to the carb. There was a partial clog in the metal line. I blew it out with compressed air and a gooey wad of old gas came flying out. Been working great ever since.
"If you hear hoofbeats, think Horses, not Zebras." If the camshaft eccentric is installed, then it can be assumed the fuel pump arm is being actuated. Now it becomes a matter of determining why no fuel is being sucked up and pumped where it needs to go. It isn't unusual for the internal in-cab tank inlet tube to have issues, it isn't "replaceable" as such, in terms of an actual separate part. It's also not unusual for the hard line to be full of sludge and sediment. On my rig it would "run out of gas" like clockwork at 1/2 a tank, eventually I replaced the tank. My theory was the pickup tube had corroded at that line level point and was sucking air. An electric pump may have greater ability to work around any slight air leaks or defects along the way, excessive crap in the tank or lines etc. Backflush with shop air, replace, etc. One of the very best things you can do on old cars for overall reliability and getting a good tune and save a LOT of time dinking around is make damn sure the fuel tank itself is absolutely clean, and all the fuel lines and hoses are unobstructed. Then test the fuel pump for the correct range of output pressure, fuel volume, and vacuum Hg on the suction side of the pump. Your vacuum gauge will do this. The carburetor must be supplied with the right amount of fuel at all times, not too much, not too little, not too much pressure, not too little, or you'll tear your hair out trying to tune it. I'd bet a 6 pack of beer when you get everything straightened out, that either or both of those fuel pumps are probably defective anyway. The last one I installed measured a static 8.5 psi, this is WAY too much output pressure and will eventually flood out the carburetor or maybe even cause a fire.
On my 1959 F100 (same tank) like F-1 said, the fuel has to be pulled vertically (up hill) from the bottom of the tank to the top of the tank and it takes a BUNCH to get it primed. My truck ran out of gas but I got lucky and coasted to a gas station. Put 10 gallons in the tank and shot some starting fluid in the carb, start and die, start and die. Got lucky again, a friend from our car club pulled into the station and came over to help. Took me spraying starting fluid while he held the throttle open to keep the engine running for about 30 seconds till it picked up fuel from the tank. My truck is running a 351W so I don't think it is just a y block issue. Three years since then (I fixed the gauge sending unit) and never had a problem since so I don't think anything was bad or broken, just hard to get the pump to prime.
I've got several setups as you describe. The cam eccentric is probably correct. BUT, make sure you reinstalled the pump back on the engine and that the arm is riding properly flat on the cam. It can be installed "crooked" slightly enough that it is just off to the side which will make it operate but not correctly and it fails quickly. You can insure the installation correctly by rotating the cam over with the starter until it reaches it's low point Another BIG thing to check is the "new" pump. A vacuum gauge is just one way. However, there has been a whole slew of rebuilt pumps out there that are being sold, that simply do not work! I have had them and know firsthand. They can be fixed by opening up the main diaphragm and then checking to see if the small valves are loose in their seats. They can usually be set back in and staked on the edge of the housing to hold them in place. The last pump I had was new/rebuilt. Before I installed it I opened the pump and both valves fell out! NOT GOOD. As mentioned before the system when working properly should pump LOTS of fuel out of the fuel line when it is disconnected from the carb. If it is not this then the line is simply plugged or you need a new sender in the tank. Any vehicle this age is subject to bad gas in the tank OR a bad tank and sender. Finally, I will say this has very little to do with being a y-block. Lack of fuel requires tracing it back to the source. Good luck with it and let us know what you find out, I hope this helps.
Follow the fuel line from tank to fuel pump. Back about 25 years ago I traded my buddy for a 65 Chevy half ton with a flatbed. Truck had a 30 gallon stainless tank in the bed. I towed it home, put a few gallons of gas in it and no gas to the carb. finally traced the fuel line and found a manual tank switching valve with the handle under the seat and the valve below the floor. It was switched to an off position. I turned it to where it was on for the line from the tank and had gas to the carb real quick. I'd replace any hose on it that looked like it was the least bit deteriorated though.
Pump the pump with your hand I’ve never had one that I couldn’t tell was working by the sound or holding my fingers over the holes. If you can put it in a vice it’s easier. When you put it in anywhere on the eccentric it should move the arm.
Well, the fuel issue is solved. I feel like a bit of a bonehead, but sometimes I am! It would appear that the previous owner had the fuel pump hooked up backwards, and as a result, so did I. I was in bed doing some research on Y blocks last night when I noticed how the fuel pump was hooked up. I thought, hey, that's the opposite of how mines hooked up. So, tonight I switched it, and there you go. Turns out a fuel pump works pretty well once you have it hooked up properly. Haha! Gotta make sure you eliminate the simple stuff first, but I didn't even think of that possibility. So, now I have fuel. I got the truck fired up, but not to stay running yet. I'll have to mess with it this weekend. I don't have much time during the week because I get home late. And since I still don't have a garage back yet, working in the dark and dirt doesn't make the job easy.
So we have a new first response to every "my fuel pump won't work" thread from here on. Are the lines hooked up to the right sides?
How good is the return spring on the fuel pump arm? That arm should be very hard to work with the pump off
Well OKAY! Great you looked at some pictures to compare. Funny how that works a lot of the time. Glad it got fixed.
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