Bogging - fuel pump? any suggestions?
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,603
Likes: 0
From: San Francisco, CA
Bogging - fuel pump? any suggestions?
I have a '71 pickup small block with a 2 barrel Rochester carb. It has a classic case of a nice heavy bog at take off. It idles fine and runs fine otherwise. I did a tuneup and rebuilt the carb and replaced float - accelerator pump seems to be working fine as I can see streams of fuel shooting into carb throat.
I see some stuff in the archives regarding fuel pump as a possible problem. Anyway to check this? Any ther ideas?
Thanks in advance guys :cheers:
I see some stuff in the archives regarding fuel pump as a possible problem. Anyway to check this? Any ther ideas?
Thanks in advance guys :cheers:
Instructor
Joined: Sep 2003
Posts: 190
Likes: 1
From: Greenville CA
Re: Bogging - fuel pump? any suggestions? (R. Bruno)
I would point you in a couple of directions: First, do you have any rubber fuel hose between tank and pump? It can suck closed. Second: you may not have the correct advance on ignition timing. If your distributor is original, the bushing may have too much play and is not feeding the correct mech advance as you try to accellerate. Check this with a timing light and dwell meter by just plotting the degrees of advance at 500 rpm increments from idle to say, 3500 rpm.
I think that when you rebuilt the carb you may have gotten part of your fuel/ignition system renewed, but now highlight another less than optimum part. Lastly, it may be that your float levels are incorrect in your carb.. Hope this gives you a couple of things to look at. :seeya
I think that when you rebuilt the carb you may have gotten part of your fuel/ignition system renewed, but now highlight another less than optimum part. Lastly, it may be that your float levels are incorrect in your carb.. Hope this gives you a couple of things to look at. :seeya
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,603
Likes: 0
From: San Francisco, CA
Re: Bogging - fuel pump? any suggestions? (mfgaffney)
Thanks Gaffney. I will check the fuel lines first. I was thinking about the distributor also and yes, it is original. So, it sounds like I take readings of the timing at the rpm increments, and then what should I be looking for?
Hopefully, I got the float correct. I measured it carefully. I am going to go bak into the carb if all else fails.
Hopefully, I got the float correct. I measured it carefully. I am going to go bak into the carb if all else fails.
Team Owner
Joined: May 2001
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
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Re: Bogging - fuel pump? any suggestions? (R. Bruno)
Fuel pump should not be a problem from idle. That is when you have the most fuel available. Fuel problems usually show up under highway speeds or when climbing hills. You will have low / no power at speed, but around the streets and idle will be fine. If your fuel pump does not have enough flow to take care of the carb after idling for a while, it wouldn't have enough for when you were on the highway.
Usually it's a float level or accelerator pump problem.
Usually it's a float level or accelerator pump problem.
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,603
Likes: 0
From: San Francisco, CA
Re: Bogging - fuel pump? any suggestions? (gtr1999)
Thanks all. Gary, I see I can still count on a wisecrack from you. :lol: I thought it was an accelerator pu,p problem at first - thus the rebuild, but I can see the fuel squirting when I tweak the throttle and I replaced the pump plunger. So, not sure where that leads me.
Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,900
From: Connecticut, USA
Re: Bogging - fuel pump? any suggestions? (R. Bruno)
:jester
You can check a fuel pump with a vac/fuel gauge,but check the rubber hose to the pump from the steel lines. I had one kinked and collapsing on a 350. It ran fine until I floored it then it would bog and choke until the foat bowl caught up. Replaced the lines and solved the problem.
:thumbs:
Gary
[Modified by gtr1999, 4:42 PM 5/3/2004]
You can check a fuel pump with a vac/fuel gauge,but check the rubber hose to the pump from the steel lines. I had one kinked and collapsing on a 350. It ran fine until I floored it then it would bog and choke until the foat bowl caught up. Replaced the lines and solved the problem.
:thumbs:
Gary
[Modified by gtr1999, 4:42 PM 5/3/2004]
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,603
Likes: 0
From: San Francisco, CA
Re: Bogging - fuel pump? any suggestions? (gtr1999)
Thanks Gary and others. I am going to replace the lines (as soon as I get time) and see if that helps (they look original and it can't hurt).
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