Engine running crummy

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Mister 4x4

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I'm way too green when it comes to carbs, but I thought I had just heard that fuel pressure over 7psi would cause this, and the optimal is considered 6 to 6.5 psi.

I have plans to install a fuel pressure regulator and gauge under the hood so I can keep an eye on mine. Not expensive at all, and should deliver the right pressure all the time.

https://www.summitracing.com/parts/sum-g3032

https://www.summitracing.com/parts/aei-15632
Great idea!

This is the setup I have on mine:  

https://www.summitracing.com/parts/mrg-9710?seid=srese1&gclid=EAIaIQobChMIi43opvvW6AIVDRgMCh2AyAAHEAQYASABEgLQ-vD_BwE

https://www.summitracing.com/parts/mrg-1561

https://www.summitracing.com/parts/mrg-1561

The Holley inline electric 'lift' pump I have only puts out up to 7psi as well.  The regulator keeps it reigned in at 5.5 psi.

 

Hemikiller

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Sometimes you just need to replace the o-ring on the seat to cure the overflow problem.
Mine has a rubber pointed tip, no o-ring. I have to get the whole needle and seat assembly.
There should be an o-ring on the exterior of the assembly. If it's missing, that's a problem. 

FWIW, I had a nasty off idle flat spot in my 71. Screwed with everything and couldn't cure it. Finally, I decided to start from ground zero, lo and behold, the primary float level was so low I could barely catch the flats with the adjuster nut. How it got like that, I have no explanation. Set it where it should be and no more flat spot...  ¯\_(ツ)_/¯

 
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Sometimes you just need to replace the o-ring on the seat to cure the overflow problem.
Mine has a rubber pointed tip, no o-ring. I have to get the whole needle and seat assembly.
There should be an o-ring on the exterior of the assembly. If it's missing, that's a problem. 

FWIW, I had a nasty off idle flat spot in my 71. Screwed with everything and couldn't cure it. Finally, I decided to start from ground zero, lo and behold, the primary float level was so low I could barely catch the flats with the adjuster nut. How it got like that, I have no explanation. Set it where it should be and no more flat spot...  ¯\_(ツ)_/¯
Oh, now I get what Tommy K was referring to. Its there and looks ok.

 I guess the same thing happened to me too? As long as it runs good that’s all that matters.

 
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Sometimes you just need to replace the o-ring on the seat to cure the overflow problem.
Hey I was thinking of the wrong thing. The o-ring is there, it’s seals around the needle and seat assembly, looks ok. I’m still just getting a new assembly for a back up. I’m sure the ethanol fuel will tear it up sooner than later. Thanks for the tip!

 

vintageman

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Not sure if it is the same on these carbs but my last bike I restored had the same type of float needles that you described. I would have to take some brasso on a q-tip and really clean the area where the needle goes into, if there were any traces of dirt or such, it would overfill the bowl. Also, check the tip of the float needle to make sure it is in good condition. Good luck.

Tom

 
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Not sure if it is the same on these carbs but my last bike I restored had the same type of float needles that you described. I would have to take some brasso on a q-tip and really clean the area where the needle goes into, if there were any traces of dirt or such, it would overfill the bowl. Also, check the tip of the float needle to make sure it is in good condition.  Good luck.

Tom
Brasso, I haven’t heard that since my military days! Ya that’s a great idea. I did try to clean that area as well as the tip with carb cleaner. I re-set the float level and it’s running like it should now. Somehow it just got out of wack.

 
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Alright alright alright! I just got back from a test drive and everything went well. Car is running great, no more hesitation and sounds really good. It started right up cold this morning and after I warmed it up too. Didn’t go to far, looks like it might rain, but far enough to be pretty sure it’s good to go, and to get a nice tire chirp or two. ?

Thanks again for all the help and I really learned some more stuff, which is always a plus!

 

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Alright alright alright! I just got back from a test drive and everything went well. Car is running great, no more hesitation and sounds really good. It started right up cold this morning and after I warmed it up too. Didn’t go to far, looks like it might rain, but far enough to be pretty sure it’s good to go, and to get a nice tire chirp or two. ?

Thanks again for all the help and I really learned some more stuff, which is always a plus!
I once had same issue, There is a curved tab on float hinge that contacts needle.  if this tab gets bent down or bent up, the float will either will flood or deprive carb of fuel. You will know this is happening if you have too little or too many theads engaging lock nut. Also holley  needle and seat assemblies  seem to be VERY sensitive to any little gremlins! squirt some silicone spray on em to lubricate, little gaskets too. 

If anybody wants to see if carb is leaking, place on bench, elevated 2 inches, fill up bowls with fuel and see where it leaking beneath from. put some food coloring in it to help spot leaks too. ::thumb::

 
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Alright alright alright! I just got back from a test drive and everything went well. Car is running great, no more hesitation and sounds really good. It started right up cold this morning and after I warmed it up too. Didn’t go to far, looks like it might rain, but far enough to be pretty sure it’s good to go, and to get a nice tire chirp or two. ?

Thanks again for all the help and I really learned some more stuff, which is always a plus!
I once had same issue, There is a curved tab on float hinge that contacts needle.  if this tab gets bent down or bent up, the float will either will flood or deprive carb of fuel. You will know this is happening if you have too little or too many theads engaging lock nut. Also holley  needle and seat assemblies  seem to be VERY sensitive to any little gremlins! squirt some silicone spray on em to lubricate, little gaskets too. 

If anybody wants to see if carb is leaking, place on bench, elevated 2 inches, fill up bowls with fuel and see where it leaking beneath from. put some food coloring in it to help spot leaks too. ::thumb::
Thanks for the tip, that’s what it seems like happened. I had taken my carb off during the winter to do some engine work, but I didn’t take the bowl off. Maybe from turning it upside down to drain the gas out? I did turn it upside down a few more times, probably quite a few more times, to adjust where the butterflies are in the transfer slots. So I may have bent the tab, but it only happened to the front, but still a possibility. Not sure, but I’m just happy that I got it running good again.

 
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John, so glad you finally got it running well. It's really frustrating when sh*t like this happens and we can't quite put our finger on the problem.

Meant as a tip, not a criticism, next time you want to drain the gas, do NOT turn the carb over. Not only can damage be done as may have happened to yours, but any dirt that settled in the bowls, will be sent into the fuel circuits. To drain the gas, just loosen or take out one of the lower bowl bolts while held over a container of course.

Now, all we need is warmer weather and be able to leave the house!

 
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Thanks Geoff, I usually do drain the gas the was you said, but I didn’t need to remove the bowls, so I just turned upside down. I won’t do that anymore.

Well, we just got 3 more weeks added to the stay at home order. But I gotta go get milk and bread and it’s supposed to be 55-60 degrees out today, so I’m taking the Mach out for a run to the store. I will definitely take the long way!! Lol

 
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Thanks Geoff, I usually do drain the gas the was you said, but I didn’t need to remove the bowls, so I just turned upside down. I won’t do that anymore.

Well, we just got 3 more weeks added to the stay at home order. But I gotta go get milk and bread and it’s supposed to be 55-60 degrees out today, so I’m taking the Mach out for a run to the store. I will definitely take the long way!! Lol
......... and watch where you park! I guarantee some idiot will pull up beside you a foot and a half off your door, even if you take up two spots.Our orders are to stay home UNLESS you need groceries, drug store or medical appt. and no gathering of more than 5 people. We can still go for walks or bike rides as long as "social distancing" is maintained.

 
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I’m disabled and can park in the handicapped spots so I don’t have to usually worry about that.
 Oh, I see. I did not know you were disabled. Handicap spots are ok, but when I had my hip replacement and needed those, I found many times that the person driving the vehicle was NOT handicapped at all, they were taking advantage of perhaps a family member who was. That's just WRONG! If you don't need it, don't use it is what I say. I still get upset when I see this going on. Wal-Mart is the worst around here.

 
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I’m disabled and can park in the handicapped spots so I don’t have to usually worry about that.
 Oh, I see. I did not know you were disabled. Handicap spots are ok, but when I had my hip replacement and needed those, I found many times that the person driving the vehicle was NOT handicapped at all, they were taking advantage of perhaps a family member who was. That's just WRONG! If you don't need it, don't use it is what I say. I still get upset when I see this going on. Wal-Mart is the worst around here.
Ya I hate that too. There’s people who are worse off than me, so I don’t always park in the designated spots. But I’m still kinda messed up from a head on snowmobile accident. I have plates and screws and a rod in my left leg and my left arm is pretty much paralyzed. I use a cane to walk when I have to go kinda far. But I do get some weird looks when I park my car in a handicap spot, but I have the special plate for it. Anyway, enough about that I’m ok.   :)

 
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I’m disabled and can park in the handicapped spots so I don’t have to usually worry about that.
 Oh, I see. I did not know you were disabled. Handicap spots are ok, but when I had my hip replacement and needed those, I found many times that the person driving the vehicle was NOT handicapped at all, they were taking advantage of perhaps a family member who was. That's just WRONG! If you don't need it, don't use it is what I say. I still get upset when I see this going on. Wal-Mart is the worst around here.
Ya I hate that too. There’s people who are worse off than me, so I don’t always park in the designated spots. But I’m still kinda messed up from a head on snowmobile accident. I have plates and screws and a rod in my left leg and my left arm is pretty much paralyzed. I use a cane to walk when I have to go kinda far. But I do get some weird looks when I park my car in a handicap spot, but I have the special plate for it. Anyway, enough about that I’m ok.   :)
 John, I'm sorry to learn about your accident, but glad you're okay apart from the extra hardware. It could have been much worse, then we would not have had the opportunity to (sort of) get to know one another one the Forum. Still looking forward to meeting you once this crap is behind us.

Take care,

 
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Ok, back to the purpose of this thread, collapsed lifters. I have still not found any evidence of fibers in the engine, or anything that would plug up the lifters so bad they wouldn’t stay pumped up. I don’t really know what the hell happened with that, my engine is running good again and hopefully that’s the end of that bs. Bad set of lifters or a bad oil filter is all I can come up with.

I did just start it up after sitting for a day and it fired right up. I’m sure its good for now, but we’ll see. Thanks again fellas!

 
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So I have been tweaking carb settings and getting my engine running really well. I was going over the build sheet for my carb and found out that my jets were 12 sizes apart! Was set up with 68’s in the front and 80’s in the rear. I always thought that they should be more like 8 sizes apart with a power valve in the front only. So I replaced the primary jets with 72’s and left the 80’s in the secondaries. Engine responded very well. It had a slight hesitation and now it’s gone. I still need to check the plugs, but I’m very happy with how it ran yesterday.

 

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