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Replacing the mechanical fuel pump, is there something I am missing???

blowedupmotor87

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So, trying to resurrect a truck that has been sitting for quite a while. It ran like a top a year ago, has sat in the same spot since until yesterday when the guy who's house it is at started it and moved it from the backyard to the front for me to look at. After he shut it off, it won't run. He poured some fuel down the carb and it ran awesome but, cut off after that starved away. (fuel lines when unbolted are dry as a desert.

So, I figure a tank sucked up something bad so, I try to hook a gas can full of fresh gas to the fuel pump to see. Siphoned gas into the the larger of the two lines line ((got a nice mouth full of gas doing that, YUCK!!!!) I assume the 3/8" line is the feed line, and the 1/4" the return?), tried to start, nothing. Lines between the pump and the carb are still dry. SO first question-, is there a manner in which I need to prime the fuel pump, or should it just do so on its own???

I went ahead and assumed it should self prime so, took the stock pump off. Now, I cannot get the new pump in!!!! I wrestled with it for 2 hours before I gave up in disgust. Even tried the old one just to see if there was a problem with the new one, can't get it in either.

I see the pushrod, I coated it in grease (figuring the surface tension of the grease would hold it up, it does but not well) and pushed it up and tried repeatedly to get the pump in. Can the pump pushrod maybe go further up into the block depending on the position of the crank???? Would I be risking any engine damage if I give the starter a bump a couple times and check to see if the rod will go further in???? (I would withdraw it as far as I can before giving the starter a bump well, no need to withdraw, it drops on its own quite readily) Just bump, check, bump, check, bump, until the point of furthest insertion???

I've not replaced a mechanical pump before so, it's a new thing to me. Any help would be appreciated because I spent most of the day today driving back and forth getting stuff for that truck and going back out to it to try and tinker on it some more (1 hour round trip to an auto parts store from where it is, and 1 hour from my house when needing to get a tool!) and I am super frustrated right now!!!!!!!! :angry1:
 
There is a single bump on the cam for the fuel pump. Turn the engine by hand 1/2 a turn and see if the rod will go in further...it should if it's currently on the bump now.
 
Thanks for the info! Did not realize it is only one lobe. Question for you though (quite possibly a dumb one)- Honestly, I cannot think of a good way to turn the engine by hand, it is in the truck and has all accessories present and accounted for. How would you suggest?
 
Usually I grab the front pulley. You could bump the starter too though, you just want it off the lobe...
 
I always turn engines over by hand by using a socket on the big center bolt of the crank pulley/harmonic balancer. You should remove the spark plugs before doing this so the motor will not have compression and you don't risk rounding off the bolt head. There are tools availible that bolt to the 3 little crank pulley bolts and you put a wrench on it to make it easier to turn over but I've never had a need for one.
 
It slides all the way to the casting in the outside of the block that catches it (the bottom of the opening that the pump bolts into) so, I assume that should be far enough? I assume that there is a seal so engine oil won't come shooting out or anything, correct?
 
I always turn engines over by hand by using a socket on the big center bolt of the crank pulley/harmonic balancer. You should remove the spark plugs before doing this so the motor will not have compression and you don't risk rounding off the bolt head. There are tools availible that bolt to the 3 little crank pulley bolts and you put a wrench on it to make it easier to turn over but I've never had a need for one.

It has a mechanical fan so I would have to take that off as well. Looks like I would have to take fan shroud off too as it is quite deep.
 
Get a remote start switch and just bump the starter with the ignition off.
You could just use a screw driver from the big terminal to the S terminal on the starter and bump it that way also on a pinch. Ignition OFF.
 
It has a mechanical fan so I would have to take that off as well. Looks like I would have to take fan shroud off too as it is quite deep.

No need to remove anything. 1/2" drive short socket, short extension and a breaker bar should do it. From the bottom of the truck.
 
If the engine has solid compression, ive never been able to do it unless the plugs are out, always felt like the bolt was gonna strip in the crank. But ive only ever really done it on new engines, or one time an engine that ended up having every rod and valve broke or bent......
 
If you look at the front of the block down by the fuel pump some of the older GM small blocks had 2 or 3 bolt holes . If you put a longer bolt in finger tight it will hold the rod up .
 
Awesome! Thanks everybody! I will be going back out there wednesday hopefully. (couldn't make it after work today, and won't be able to tomorrow)
 
Probably flooding, float stuck or too much pressure from pump which is not uncommon with aftermarket pumps
 
Probably flooding, float stuck or too much pressure from pump which is not uncommon with aftermarket pumps

Hopefully not a pump issue, I don't want to have to wrestle another pump on!

There may be more carb issues but, the most noticeable issue is the gas dripping out of the accelerator pump onto the intake. Owner says as part of the trade, he will give me another, fresher carb. So, hopefully he follows through with that! (and hopefully that will fix the issue)
 
Leaking out of the acc pump could be float setting too high, heavy float or stuck needle seat.
Tap in the side of the carb with handle side of a screw driver and see if it clears up indicating a stuck needle or some junk stuck in it.
 
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