|
|
10-06-2013, 03:39 PM
|
#21
|
Montana Master
Join Date: Feb 2005
Location: Haysville
Posts: 4,261
M.O.C. #3085
|
All good ideas so far. Would you know if your truck has a Quadrajet or Holley carb? If it's a Holley, you may get by with just changing bowl and metering plate gaskets as they dry out and seep in scenarios like yours. If it's a "quadrabog", looking at the carb upside down there are 4 holes ahead of the primary throttle butterflies ... mix up some epoxy and coat the plugs inside the forward holes as they can leak fuel out of the fuel bowl on older carbs. Clean varnish off plugs first. http://image.highperformancepontiac....carburetor.jpg If all these responses fail, you may have a "Lankstrom Strangley Valve " on the fritz or the torque on your muffler bearing has loosened up.
|
|
|
10-06-2013, 03:43 PM
|
#22
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
I will have to get info off the tag.. if I can find it. This a winter project when I get some down time.. furnace start-up time, so that may be a while, but I will keep all this info and it will guide me through the fix. thanks to all of you, thanks for the carb info Dieselguy!
|
|
|
10-06-2013, 04:24 PM
|
#23
|
Montana Master
Join Date: Oct 2007
Location: silver creek
Posts: 1,507
M.O.C. #7770
|
OZZ, a holley will be clearly marked on the fuel bowls. If you notice the picture,a quadrajet has two large secondary's and primaries are small in comparison. my bet is if the engine is original it has a quaddrajet. Ford is the only company that I remember in the 70's and early 80's that used a holley style for certain motors
|
|
|
10-07-2013, 01:54 AM
|
#24
|
Montana Master
Join Date: Jan 2009
Location: Vermontville
Posts: 1,129
M.O.C. #9045
|
Agree that the system is simply bleeding down and or evaporating. This is not good on carb or pump. As others have said it's easy to change the pump out with just 2 bolts and taking the lines off. But as others have said the rod likes to slide down, but will add if the rod doesn't want to go back up in after taking the pump off you simply need to bump the starter a tad and the cam will get of the high side and the rod will go further back up. On the other hand a good fix would be to take the time and go out and start this vehicle once a month and you will keep the system from bleeding back down. This will keep the gaskets and the diaphrams (sp) wet which is needed. With you stating that once it gets started it starts easily I would say there is nothing wrong with either the pump or the carb, it just needs to be started more often.
Dave
|
|
|
10-07-2013, 02:17 AM
|
#25
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
Dave, thanks for the tips on the rod. No one is around for the long down time when it sits, when we are away.
|
|
|
10-07-2013, 02:18 AM
|
#26
|
Montana Master
Join Date: Aug 2007
Location: Waterford
Posts: 3,693
M.O.C. #7500
|
Ozz, I won't resay what everyone else has said except to offer an explanation and a tip. Your fuel pump is a diaphragm type pump, and the diaphragms do wear out over time and cause not only "leak down", but eventually other problems like stalling and poor or sporadic acceleration.
When changing, you will find there is a rod that is driven off the camshaft that presses against the arm on the pump. Getting that rod back in place while trying to install the pump is an exercise in frustration unless you do this: at the front of the block, you find a bolt (I believe it's on the timing case cover, but it's been years since I've done one of these). the bolt hole is drilled and tapped all the way through to the hole the rod that drives the pump. taking out the existing bolt will allow you to hold the rod in the up position while you screw in a longer bold to hold it there so you can slip the pump arm in with no problems. Just don't forget to replace the bolt with the original one when done.
|
|
|
10-07-2013, 02:26 AM
|
#27
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
Thanks Tom, this is the second time I have read about that bolt-hole, racerjoe mentioned it as well, I will look for that, but I might block that off and install an electric pump, probably close to the same money, if I don't have to buy a bunch of pre-formed gas line.
Ozz
|
|
|
10-07-2013, 04:12 AM
|
#28
|
Montana Master
Join Date: May 2011
Location: Fayetteville
Posts: 4,200
M.O.C. #11401
|
Ethanol evaporates quickly. Lots of small engine devices have warnings on them to not use it. There are cos that still offer fuel without it. There was none in 76. Modern fuel systems use materials the alcohol doesn't affect . I agree with suggested repairs if changing the fuel doesn't correct the issue. Also recommend using the alcohol free fuel after repairs for longevity. IMHO
|
|
|
10-07-2013, 04:23 AM
|
#29
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
Duly noted Larry
|
|
|
10-07-2013, 03:59 PM
|
#30
|
Montana Master
Join Date: Oct 2011
Location: Lykens
Posts: 545
M.O.C. #11842
|
All I do is open the hood and squirt some starting fluid into the air cleaner housing. The engine will start using the starting fluid and run long enough to replenish the fuel supply in the carburetor bowl. You already know how much time has to pass before you will have to do this. Sounds like it runs ok after starting so the fuel pump must be fine. Don't fix it if its not broke.
|
|
|
10-07-2013, 11:05 PM
|
#31
|
Montana Fan
Join Date: Mar 2011
Location: gresham
Posts: 489
M.O.C. #11202
|
Quote:
quote:Originally posted by Tom S.
Ozz, I won't resay what everyone else has said except to offer an explanation and a tip. Your fuel pump is a diaphragm type pump, and the diaphragms do wear out over time and cause not only "leak down", but eventually other problems like stalling and poor or sporadic acceleration.
|
I would also suspect a bad diaphragm on the accelerator pump of the carb. If it is rotton or has enough of a hole in it, it will not spray enough fuel(or possibly none) down the carb throat when you depress the gas pedal.
When you use starter fluid, it is essentially doing what the accelerator pump should be doing, and it will get the engine firing enough to get the suction necessary to draw fuel from the float bowl, through the jets, and keep running. If it is the diaphragm, you may also notice some lag time from when you step on the gas and when the engine starts pulling, feeling sluggish in accelerating.
|
|
|
10-08-2013, 02:47 AM
|
#32
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
I'll take the old gal out for a short trip and check what she does, you get so used to the way they drive, you don't pay much attention. Thanks.
I have the third engine in it, the first, I removed, rebuilt.. had it done, and it went into my old 1967 28'wood Owens cruiser, the second engine one of my guys burned up driving 70 in second gear.. this is the third, so I don't know what carb I have on it, I will find out.
|
|
|
10-08-2013, 03:32 AM
|
#33
|
Seasoned Camper
Join Date: Jan 2013
Location: Twin Falls
Posts: 50
M.O.C. #13130
|
Ozz,
That is a common problem with Quadrajet carbs. In the bottom of the float bowl there are two passages that are sealed with lead plugs.
These will leak and the float bowl will drain empty. The best fix that I have come up with is what is called a super gasket. It is just a hard foam gasket that fits between the pass plate and the bottom of the float bowl. Any good automotive parts store should now about this and help you out. You do have to take the carb off and take apart. Good time to rebuild.
Dan
|
|
|
10-08-2013, 04:16 AM
|
#34
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
thanks!
|
|
|
10-08-2013, 08:51 AM
|
#35
|
Montana Master
Join Date: Aug 2007
Location: Waterford
Posts: 3,693
M.O.C. #7500
|
Quote:
quote:Originally posted by PaDan
Ozz,
That is a common problem with Quadrajet carbs. In the bottom of the float bowl there are two passages that are sealed with lead plugs.
These will leak and the float bowl will drain empty. The best fix that I have come up with is what is called a super gasket. It is just a hard foam gasket that fits between the pass plate and the bottom of the float bowl. Any good automotive parts store should now about this and help you out. You do have to take the carb off and take apart. Good time to rebuild.
Dan
|
Yeah, I forgot about the plugs in the QJ's. Shows how long it's been since I've messed with one. Another common problem was the accelerator pump. I replaced more than one of those! But I digress, since the accelerator pump is not Ozz's problem.
|
|
|
10-09-2013, 12:52 AM
|
#36
|
Montana Master
Join Date: Jan 2009
Location: Vermontville
Posts: 1,129
M.O.C. #9045
|
One thing for sure Ozz, it's an old enough vehicle that you can actually work on it. These new ones I haven't even found the engine yet when you open that hood! lol
Dave
|
|
|
10-09-2013, 01:32 AM
|
#37
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
I about passed out when I opened the hood on my Super-Duty; two turbochargers and 7 radiators. If you left a shop rag on the engine... stuff, you wouldn't be able to close the hood
|
|
|
10-09-2013, 04:26 AM
|
#38
|
Montana Master
Join Date: Jan 2013
Location: Depends on temps
Posts: 1,648
M.O.C. #13157
|
Ozz, My vote is for well plugs leaking. A 76 GM 350 will have a Quad J on it. Guys, we all telling our ages. If it starts, runs, and drives fine the fuel pump is not the problem.
Jim
__________________
2012 Ram Laramie 3500 DRW 4x4 3.73 Tow Max Pkg B&W Companion 60 gal RDS aux fuel tank. 2014 Montana 3150RL, 2 A/C's, Leather, 6 Point Jacks, Splendede WD2100XC, Mor/ryde X-Factor, Duravis 250 tires with TST 507RV monitors. 2 x Honda EU2000's
|
|
|
10-09-2013, 04:29 AM
|
#39
|
Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
|
I think we have a pretty good bunch of Gear-heads here. Thanks, darned ole well plugs!
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Threads |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|