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fez68 Samba Member
Joined: December 12, 2015 Posts: 242 Location: massachusetts
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Posted: Mon Sep 06, 2021 5:52 am Post subject: hesitation at constant throttle |
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I am having a problem with my friends bug i am heling him with .
It accelerates great , but when your cruising at a constant speed ,i can feel it has a slight hesitation, was thinking it could be the fuel pump . Any thoughts on this ? thanks.
1600 dp , rebuilt 34 pict3 from volksbits. all new intake / exhaust gaskets and intake boots. svda bosch dist., new cap ,rotor, points and condensor, new plugs and wires, timing at 7.5 idle , 29 full advance with hose off and plugged. Valves adjusted . |
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vamram Samba Member
Joined: March 08, 2012 Posts: 7274 Location: NOVA
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Posted: Mon Sep 06, 2021 6:43 am Post subject: Re: hesitation at constant throttle |
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Have you checked the fuel level in the bowl immediately after one of these runs? I've assuming you have a Bentley to look up the value as I don't know it off the top of my head, but if the pump isn't putting out enough volume at speed that could be one cause of that. Also, what size main and idle jets did Tim install on the carb? _________________ Eventually, "we are what we pretend to be.’”
Give peace a chance - Stop Russian-Soviet Aggression!!
'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...waiting it's turn in line behind '74.
Click to view image
Save the Supers!! |
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fez68 Samba Member
Joined: December 12, 2015 Posts: 242 Location: massachusetts
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Posted: Mon Sep 06, 2021 7:09 am Post subject: Re: hesitation at constant throttle |
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I havent checked the bowl level. i do have the bently manual though. The carb is straight from tim and was just intstaled , so assumed he set the float level already.
I dont know what jets tim installed. I had him set it up for a 1600 with svda and 34 pict 3. just like my engine has and mine runs great.
thanks for your help |
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fez68 Samba Member
Joined: December 12, 2015 Posts: 242 Location: massachusetts
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Posted: Mon Sep 06, 2021 7:10 am Post subject: Re: hesitation at constant throttle |
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sorry , i see what your saying check the fuel level not the float setting . ill look into it. |
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68IHscout Samba Member
Joined: March 10, 2010 Posts: 3122 Location: santa ana ca
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Posted: Mon Sep 06, 2021 9:47 am Post subject: Re: hesitation at constant throttle |
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i am having almost the same issue (higher rpm hesitation ) it will be interesting to me what you find , i am also leaning towards fuel pump but have to run tests . |
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VW_Jimbo Samba Member
Joined: May 22, 2016 Posts: 9879 Location: Huntington Beach, CA
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Posted: Mon Sep 06, 2021 9:55 am Post subject: Re: hesitation at constant throttle |
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Check the fuel filter?
And be sure there is not more than one of them!
Also, sometimes it is the filter sock in the tank.
Seen a kinked fuel line exhibit the same complaints. _________________ Jimbo
There is never enough time to do it right the first time, but all the time necessary the second time!
TDCTDI wrote: |
Basically, a whole bunch of fuckery to achieve a look. |
67rustavenger wrote: |
GFY's Xevin and VW_Jimbo! |
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fez68 Samba Member
Joined: December 12, 2015 Posts: 242 Location: massachusetts
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Posted: Mon Sep 06, 2021 10:57 am Post subject: Re: hesitation at constant throttle |
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I just replaced the fuel filter and lines last month, when i put his engine back in. I believe the problem is rust in the tank /metal fuel line. I swapped out the pumps and when i did no gas was coming out of the fuel line from the tank. I checked the fuel filter and there was only a small amount of fuel in it and i could see allot of small rust particles. He drove it about 20 miles to my house . But now it wouldnt even start and i saw no gas in either fuel line. I blew the line out with compressed air and he could hear the air going into the tank. put it all back together and now the gas is flowing out of the line from the tank at the pump. and we took it for a test drive and it is still a little hesitation. but better. i think that the line is clogged / restircted and the pump is having to suck the gas out of the line, so its not enough flow. seems better bow but i think we need to remove the tank and check all the lines and tank for rust . maybe run something through the line like a brush and then clean it all out. |
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Igpoe Samba Member
Joined: February 24, 2019 Posts: 853 Location: South Boston, VA
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Posted: Mon Sep 06, 2021 12:34 pm Post subject: Re: hesitation at constant throttle |
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I'd bet you need to replace the sock in the tank. _________________ '73 super. |
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68IHscout Samba Member
Joined: March 10, 2010 Posts: 3122 Location: santa ana ca
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Posted: Mon Sep 06, 2021 12:45 pm Post subject: Re: hesitation at constant throttle |
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fez68 wrote: |
I just replaced the fuel filter and lines last month, when i put his engine back in. I believe the problem is rust in the tank /metal fuel line. I swapped out the pumps and when i did no gas was coming out of the fuel line from the tank. I checked the fuel filter and there was only a small amount of fuel in it and i could see allot of small rust particles. He drove it about 20 miles to my house . But now it wouldnt even start and i saw no gas in either fuel line. I blew the line out with compressed air and he could hear the air going into the tank. put it all back together and now the gas is flowing out of the line from the tank at the pump. and we took it for a test drive and it is still a little hesitation. but better. i think that the line is clogged / restircted and the pump is having to suck the gas out of the line, so its not enough flow. seems better bow but i think we need to remove the tank and check all the lines and tank for rust . maybe run something through the line like a brush and then clean it all out. |
when you get as far as the steel lines ,just get a couple of parts cleaner aerosol cans and spray it inside the line till it comes out the other side (place a rag on the end to catch debris) repeat when can is empty .
After cleaning tank and hard lines ,install filters (and new hoses)and change filters after hundred miles or so, good luck. |
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fez68 Samba Member
Joined: December 12, 2015 Posts: 242 Location: massachusetts
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Posted: Mon Sep 06, 2021 1:58 pm Post subject: Re: hesitation at constant throttle |
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[quote="Igpoe"]I'd bet you need to replace the sock in the tank.[/quot
thanks for your input. |
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fez68 Samba Member
Joined: December 12, 2015 Posts: 242 Location: massachusetts
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Posted: Mon Sep 06, 2021 1:58 pm Post subject: Re: hesitation at constant throttle |
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68IHscout wrote: |
fez68 wrote: |
I just replaced the fuel filter and lines last month, when i put his engine back in. I believe the problem is rust in the tank /metal fuel line. I swapped out the pumps and when i did no gas was coming out of the fuel line from the tank. I checked the fuel filter and there was only a small amount of fuel in it and i could see allot of small rust particles. He drove it about 20 miles to my house . But now it wouldnt even start and i saw no gas in either fuel line. I blew the line out with compressed air and he could hear the air going into the tank. put it all back together and now the gas is flowing out of the line from the tank at the pump. and we took it for a test drive and it is still a little hesitation. but better. i think that the line is clogged / restircted and the pump is having to suck the gas out of the line, so its not enough flow. seems better bow but i think we need to remove the tank and check all the lines and tank for rust . maybe run something through the line like a brush and then clean it all out. |
when you get as far as the steel lines ,just get a couple of parts cleaner aerosol cans and spray it inside the line till it comes out the other side (place a rag on the end to catch debris) repeat when can is empty .
After cleaning tank and hard lines ,install filters (and new hoses)and change filters after hundred miles or so, good luck. |
good idea👍 |
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[email protected] Samba Member
Joined: May 17, 2003 Posts: 4863 Location: Harmony, PA
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Posted: Mon Sep 06, 2021 7:02 pm Post subject: Re: hesitation at constant throttle |
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I fought a similar issue, and the last item that fixed the problem was installing a new metal chassis line from the tank. The og one was rusted internally, and would continually flake rust particles off into the filter, eventually clogging it. |
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