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power loss, like zero power


high winder

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okay so I had some troubles here awhile back with the dizzy somehow coming loose. got all that fixed and things were running fine.

then on Thursday I go to start it and noticed it drug when I started it like the timing slipped. anywho I drive home and all is well until the following day. starts dying as soon as I let off the gas, runs rough etc.

 

I check timing i'm right at 5 BTDC, when I hand throttle it, it advances on up to 20 like it should I think, I looked for vacuum leaks and didn't find any, it  idles like a champ, it revs perfect when I throttle it with my hand off the carb but when I try and drive it the car falls on its face, doesn't want to rev, runs like chit.

 

not sure if its timing, a bad vacuum advance or something else.

 

elec ign. and its a 5 spd

 

any advice would be greatly appreciated

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When driving, your foot goes to the floor and power drops off and you have to let up just to keep a steady speed? Car goes slower and slower up a hill? Will go faster down a hill but on the level, drops back to the same speed as before.

 

It revs up ok in neutral because it doesn't take much gas to spin 50 pounds of crank and pistons. But pull  2,000 pounds of car along? forget it.

 

If you can drive it as much as you can under load, say 10 min.  Pull a plug. If the porcelain tip is bright white you are running over lean. Primary jet is likely part clogged. Lean running overheats the plugs and burn all the deposits off. White porcelain ... lean.

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yep you got it, idles revs great until under load then it falls flat goes slower and slower up hill, wants to back fire sometimes...

 

so I pulled the plugs and they are all just very light tan color, no wetness, oil residue nothing.

 

okay so on the weber 32/36 do I just look into it and unscrew the jets or are they on the side somewhere??

 

you guys rock

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yep you got it, idles revs great until under load then it falls flat goes slower and slower up hill, wants to back fire sometimes...

 

so I pulled the plugs and they are all just very light tan color, no wetness, oil residue nothing.

 

okay so on the weber 32/36 do I just look into it and unscrew the jets or are they on the side somewhere??

 

you guys rock

Your turn. Go look up a jet replacement how to on Google. Then clear the clog. It's easy,

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Possibly that, but I've had this on a B-210 and the engine sputters and jumps on and off like running out of gas. The plugged jet seems like power just drops off as you push the throttle down. Carb makes a louder groan as more air is added until the mixture is so weak it will sometimes backfire. Plugs were whiter than new

 

Try it, it's only $4 or $5 for a filter and no harm trying..

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Okay..Got it all tore down and installed back on the car.

 

Runs like a champ with way more power but....

It idles really high and I'm adjusted all the way out.

Timing is good so my question is what could cause it.

 

The primary and secondary jets looked like the same size so I didn't pay attention which one went where.

 

When I pulled the imultuon tubes the primary was a real PITA , when I got it out I noticed a small crack by one of the holes, since I didn't have another I reinstalled it. Could this cause the high idle.

 

Thanks for the SBS, gigantic help.

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Fast idle causes...

 

Throttle cable too tight

Choke on or not shutting all the way off causing fast idle cam to engage or fast idle cam stuck.

Secondary throttle plate stuck part open or foreign object caught in it.

Primary throttle shaft worn causing misalignment and sticking of throttle plate.

BCDD set too sensitive and not releasing.

Timing too advanced because idle too high upsetting vacuum and mechanical advance.

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yep you got it, idles revs great until under load then it falls flat goes slower and slower up hill, wants to back fire sometimes...

 

so I pulled the plugs and they are all just very light tan color, no wetness, oil residue nothing.

 

okay so on the weber 32/36 do I just look into it and unscrew the jets or are they on the side somewhere??

 

you guys rock

The Idle jets are on the sides, mains are at the bottom of the float bowl, Try clearing the Air Corrector jets with carb cleaner at a high idle through the top pf the carb, you can see them, w/o removing the top

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I'm gonna take a look at the secondary throttle plate, when I was putting it back together it just didn't quite

Want to close when I ran the linkage, I noticed it had a tiny burr on the very edge of the barrel where the shaft comes out. I cleaned it up with 1000 grit emery cloth until it worked. I'll check bushings as well.

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Boost controlled deceleration device.  On deceleration the carb is at idle but the intake vacuum is very high from the high RPMs.The mixture that enters the cylinder is very weak and does not burn well and lots of un-burnt hydrocarbons are dumped out the exhaust. When the intake vacuum rises above a pre set limit the BCDD opens a small passage and mixes a proper amount of gas and air and feeds it to the engine so it can assist in the complete combustion and lower the HC level. It's basically a very small carburetor within  the carb. When the vacuum level drops the BCDD shuts off. It is possible for the BCDD to be set too sensitive and normal intake vacuum will hold it open and raise the idle speed. 

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