June 8, 2011 at 8:28 pm #233505
Here whats goin on. Runs to 55mph no faster. Ran out of pedal. I have a 75 1600 with duel carbs. I think I may need to adjust the fuel flow up or possible a timing adjustment. Just some ideas. what do you think?June 8, 2011 at 8:49 pm #245056
Tune it. Sparks first. points (or pertronix), timing, etc. THEN look at the carb, fuel filters, flow, throttle linkage. You’ll get it.June 8, 2011 at 8:56 pm #245057MarkParticipant
Newbie Question: What is “tuning”?June 8, 2011 at 9:23 pm #245058Peter C. KingParticipant
Has your throttle cable slipped out of the friction lock on the carb linkage? Put a brick on the gas pedal (engine off) and look at the carb. Can you advance the linkage further? If so, adjust the linkage at the carb.
Has the throttle cable stretched? Is it coming apart inside the tube? That could lengthen the cable and give you less throttle. Buy a new throttle cable.
It happened to me on a 69 microbus on a cold winter’s night. I made it home with a piece of fence wire for a throttle cable.
If the linkage is fully advance at full throttle, follow Edsnova’s advice.June 8, 2011 at 9:45 pm #245059
most of it is new. will be going over it tomarrow.June 9, 2011 at 12:15 pm #245060
Is it possible the 009 dist. is not advancing causing it to flatten out at 55?June 9, 2011 at 12:25 pm #245061MarkParticipant
Dummy me. Tune UP. I got easily thrown by tune IT. Spark plugs, points, condenser, set the timing, all after a valve adjustment.June 9, 2011 at 1:59 pm #245062
I just ordered a new electronic dist. All the rest have been checked and adjusted.June 9, 2011 at 2:04 pm #245063
I like B’s idea. Bridget’s cable ended up wrong after I replaced the gas pedal. My problem was opposite–idle was about 3k. Fixed it in 1 minute by loosening the cable at the carb, setting it just not quite tight with the new roller at rest.
Sparks are in order, so on to the fuel.June 9, 2011 at 2:15 pm #245064
I have new dual carbs and new heavy duty throttle cable with housing. I adjusted the fuel regulator up to alow more fuel in. no change.June 9, 2011 at 9:45 pm #245065newkitmanParticipant
Even with dual carbs (I have dual 34mm Dellortos) the fuel pressure should be no more than 4 psi. Mine’s set at 3 1/2 psi and works fine. My thinking is the gas cable is set wrong. Low fuel pressure would be low at idle as wall and you say it works well at idle. My 02 cents worth.
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackJune 9, 2011 at 10:06 pm #245066Peter C. KingParticipant
How does the engine run at 55? Is it spluttering and spitting or does it sound normal? Fuel starvation would cause it to splutter. Lack of advance would caue it to seem to run normally but keep it from going faster.
Have you checked the vacuum hose to the distributor? Is there one? is it connected at both ends? Pull it off the distributor with the engine running. Is there vacuum? Are the ends split?
What you describe could be lack of enough vacuum to advance the distributor. That could be as simple as a bad vacuum hose.
If the hose appears OK, look at the advance plate in the distributor. You should be able to move it enough to know that it moves. Are the springs intact? Pull a vacuum on the hose and see if the vacuum pot tries to move.
PCKingJune 10, 2011 at 11:05 am #245067
If you are running dual Solex’s (35 PDSIT’s or Kadron’s) you want no more than 1.5-2.0 psi fuel pressure MAX.
More fuel pressure will just flood the car by blowing the inlet needle seats, overflowing the bowl and come out the vent tubes into the carb verturis.
Dellorto and Weber IDF’s like 3.5 psi max.
009’s are mechanical advance…not vacuum. They cause an off-idle flat spot in some applications. It depending their country of manufacture, the advance curves are different. they would not cause the engine to go flat through the entire RPM range.
What dual carbs are you running? Is it running all 4 cylinders? (check each exhaust port at idle.)
Fuel delivery pressure is likely NOT your problem. Sounded like your throttle cable was not adjusted to allow WOT, but now keep reading.
You said the carbs are new? Whose were they? Sometimes they are full of cosmoline and stuff and need to be disassembled and cleaned throughly BEFORE you install them…especially stuff from “offshore” suppliers. You could have a clogged main jet or debris in both.
I bought a single Weber 40 IDF from CB Performance and they claimed they disassemble, clean and re-jet the carb for a basic jetting at sea level. I’ve not taken a really close look at it yet, but it looks like they had it apart. I will do the disassembly and clean anyway when I get ready to mount it.
If it’s not popping and sputtering, it’s probably not electrical, but a Pertonix Ignitor and their matching coil will wake up the spark and are trouble free. However, DON’T use them with a Bosch “Blue” coil. The “blue” coil has an internal resistor that knocks the primary voltage down to about 7 volts. This defeats the beauty of the Peretronix Ignitor…12 volts primary makes a much hotter secondary spark. That’s why we have electronic ignitions since 1974…more primary juice…more secondary juice (spark).
Pink MG40704.4759606481June 14, 2011 at 4:17 pm #245068
Not fixed!!! Dual Empi 34’s. Flamethrower 009 no vacum advance. I set the timing at 0 tds and it ran terrible. Now I adjust it where it sounds right. This engine is not factory and appears to an after market mill or 75 and up FI but not sure. When I push the pedal down the carbs throttle are maxed. The fuel system is clean and I watched the fuel flow into each carb.June 14, 2011 at 9:16 pm #245069
Valves? valve springs?
reaching here but I do remember a Car Craft big block chevy build from back in the day. They rigged it up nice, big cam, the works, unleashed her on the strip and the engine laid down at about 5500. Should’ve revved to about 7k, 7500. Turned out the cam mfg had shipped the wrong springs.
I know, long shot. I’m still thinking spark but I am not knowledgeable.June 14, 2011 at 10:29 pm #245070
I think I am going to take it to a friend and see what he can figure out. Talked to one guy who charges 65 an hour. Not going to happen! Wrong economy! I’ll keep on it anyway and thanks to all of you for your help!June 15, 2011 at 11:02 am #245071
Richard, to set the timing on a 009, you need to rev it to 3,000 RPM and hold it there and set it at 28-30 degrees advanced. Do you have a degereed pulley? This usually backs down to about 7.5 degrees or so at idle.
Did you check to see if it’s “hitting” on all four cylinders? Check your firing order a couple more times…a crossed wire could do this.
Fuel can flow into the carbs, but there may be passages in the carbs that are clogged. What jets are in the carb? I trust nothing that comes from EMPI…it’s all Chinese stuff.
Have you posted the problem in the High Performance Engines section of the SAMBA forum?
Pink MG40709.462037037June 17, 2011 at 3:54 pm #245072
I did post on samba. I’m going to take the car to a friend this weekend.June 20, 2011 at 1:07 pm #245073
Let us know what the diagnosis and fix was…hope it’s a simple fix, not at flat cam lobe or weak valve springs.August 26, 2011 at 10:28 am #245074
Update! Problem appears to be the throttle cable with the plastic tube. Didnt work for me and I wont use on again.
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