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VW Beetle (older / air cooled models) Maint. & Repair

ratbert1ratbert1 Posts: 72
edited March 2014 in Volkswagen
I have a 1974 super beetle. It hasn't been started in years. I got the engine to fire for about 5 seconds, but now it won't anymore.

What I've done so far:
1. drained gas and replaced with new gas with sta-bil
2. removed and completely cleaned carb.
3. cleaned electrical contacts to the point where the engine will turn over.

What I intend to do:
1. remove spark plugs and clean/regap/replace.
2. check point gap.
3. Clean rotor.

It's been such a long time since I worked on a carb engine. What else can I check? Any troubleshooting tips?


  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,488
    Forget the carb---an engine will fire even with the world's worst carburetor (might not run well, but should fire).

    You need to verify compression, and then I'd replace the plugs completely, as well as the ignition points if that's what that car is still using.

    Just throw away the old plugs. If you have compression, the car should fire with new plugs and a decent point gap.

    If this engine has sat for a very very long time, there is a chance that the piston rings have frozen (rusted) to the bottoms of the cylinders, so you could have cylinder wall galling or broken rings as well. Flat engines don't like to remain unused for years.

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  • swschradswschrad Posts: 2,171
    turning periodically a turn or two with a wrench on the crank bolt over a couple days until you feel reassured and put the plugs back in for a test?

    the only frozen engine situation I have heard about with any success was off an old '27 whippet that was rebuilt for a radio station's 60th. they put the block in a washtub full of kerosene, poured more in the cylinders daily, and whacked on the pistons with a log and a sledge until they came out (crank had previously been removed.)

    the engine didn't last, but it worked for two parades when rebuilt.

    the bug probably isn't that bad off, but wouldn't soaking the power head out in penetrating oil and turning it periodically clear the ring freeze issues?

    wouldn't fix any rings that have already broken under movement, of course.

    OR.... would the best course just be to pull the mill, open it up, and do a ring job on general principle?
  • to clarify - the engine is not frozen. It turn over again and again when I try to start it. It just won't fire anymore.

    Tonight I replaced the plugs and points after inspecting them. No salvaging the plugs. black and messy (not just a carbon film). Points were worn.

    Fortunately my father left me with a couple boxes of parts so I just have this stuff.

    Even if there were no compression, wouldn't it still fire except that I would have no horsepower? It's gas. Could it be that the fuel still in the line from the tank back to the engine is so old that it won't burn? At the worst, it's like 2 years old. I guess I need to invest in a compression tester.

    Also, I made a habit of turning the engine by hand every so often when it say there. Never had any trouble or sign of something being stuck.
  • swschradswschrad Posts: 2,171
    if you don't know about the fuel, the magic book of "dunlosin" says drain it, pour in fresh, and replace the fuel filter. there will still be somewhat less than a cup of fuel in the carb bowl and the fuel lines that is nicht so gut, so you wouldn't see results until you cranked it out or drained it out of those areas as well. dripping fresh fuel into the carb bowl and getting little barks of power from the engine might signal your tank of gas is useless... or your fuel pump is useless. disconnect at the carb and see if you can crank a cupfull in under a minute. if so, pump is good enough.

    you don't necessarily need a compression tester if you can whittle some wooden plugs. put 'em in the plug holes. if they blow out with a satisfying POP! when you turn the crank by hand, there's enough. be sure the plugs can't be sucked into the engine by whittling soft wood, way down in size, so there's no way they could be sucked in.

    a no-compression engine can't pack the gas/fuel mixture tight enough so its expansion on sparked explosion doesn't generate enough energy to turn all that steel around and around. so it won't ever start.

    you could also use an ohmmeter to check the plug wires end to end... if they are over 30,000 ohms, there are enough breaks in the conductor (carbon fiber, usually) so you are blowing away all your spark power in widening the gaps in the conductor. just for grins, hook an old plug up to one of the plug wires, use a clip lead to tie the outside gap side to engine ground, and see if you generate a spark when you crank the beast. if not, the coil may be no good. don't hold it, spark voltage is dangerous.

    I was going to add if you can get your hands on a timing light, would be interesting to see what your spark angle is, measured from the marks on the crankshaft. but if nobody has munged around with the distributor setting, it's probably close enough for shade-tree testing.
  • I'm pretty sure the wires are good, but I'll check. Also, I can use the timing light to see if current is going through the wires!

    Still what get's me about all this is that I got it to start and run for about 5 seconds. lots of smoke, but it ran.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,488
    You need about, roughly, 75 lbs of compression to fire the cylinder, minimum.

    If a flat engine sits for a long time, the bottoms of the pistons just sit in the cylinder bore, and moisture collects at the rings. The rings then rust to the cylinder and when you move the engine for the first time in years, the rings break off...or...they don't break, but you have this "rust ditch" from galling on the cylinder wall, and compression escapes past the rusty rings.

    If you have compression, some fuel dribbling in from somewhere, and a good fat spark, this engine will run--maybe not well or for long, but it will run.

    A gentle push start might be the answer, especially if the old starter motor is dragging and not spinning the engine fast enough.

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  • You can take off the coil wire from the center of the dist. cap and hold the end close to a metal part to see if you have a spark jump. Spark should be whiteish not yellow. Hold the end with a rag so you don't get jolted and have someone crank the engine over a few times. If no spark from coil, check for battery voltage to coil.

    If you have spark from the coil you can check out the sparkplug wires by pulling one off the sparkplug side and using a screwdriver in the end hold it close to a ground point and have someone again crank the engine to check for spark.

    Can you smell gasoline when it is cranking over? you might have water in you gasoline from sitting so long. Drain the gas out of the tank put in fresh and use some dry gas to remove water.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,488
    Also be real careful as VW engines like to catch fire sometimes.

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  • Also, watch your finger and hands when working around moving parts. If you are not sure about what you are doing, leave it to a professional.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,488
    I'm just a little concerned because if you are trying and trying to start an air-cooled VW, with that carburetor perched right above the distributor cap and wires,'s risky if you start flooding the carb.

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  • I am knocking around the thought of buying a Type 3, not sure which style. Has anyone on this board been keeping one going. How hard is it to get parts compared to a Bug? I do not own a VW at this time. I learned to drive in a bluegreen '74 super and remember it as a great car except for the fact it melted my tennis shoes to the floor that were setting by the rear heat hole! The car was smashed by a Power company line truck while it was setting in our driveway! My mother drove a 411 squareback for years so I know a little about them.
  • I've had the engine catch fire once many years ago. Not cool. But now I have a fire extinguisher sitting right next to the enginer when I'm trying to start it.

    I've checked the plug for spark using a timing light at there's at least something going to the plug. My next stop is to get a compression tester, but I've been unterbelichte for a few days so I haven't gotten it yet. My hopes are dwindling for an easy resurrection.

    chrisducati - type-3 vws are not as popular as bugs and they are a little harder to find parts for, but do a google search for type 3 parts and you'll find a lot of resources. I was actually thinking of getting one as a project car, or possibly a Thing. :) I don't want to do too much with the bug I'm working on now because it has HUGE sentimental value.
  • swschradswschrad Posts: 2,171
    if ever you wanted to rebuild an engine, the old bug mills are a great place to start, and there are still parts out there easily gotten.

    have not opened the two big sealed parts myself ;), but I hear the watchword is buy your penetrating oil by the gallon, and take real long breaks between applications.
  • I finally got over my cold. So I disconnected the fuel line from the pump to the carb and pointed it into a can. Turned the key and no fuel came out. So I jacked up the front and pulled the fuel line off the fuel filter that was under there. I think the filter there is like 20 years old because my father never knew it was there. My intent was to drain the tank and check the tank filter screen. The fuel dripped at 1 drip/second out of the filter. So once the tank is drained, I'll remove the filter from under the front and put in a new fuel line under there, with no filter.

    What can I do with the old gas once it's drained?
  • swschradswschrad Posts: 2,171
    mold it into ashtrays?

    there are volatile sections of gasoline that will certainly have vaporized long, long years ago. what's left will have a bunch of lacquer in it, and is as likely to burn properly in a cylinder as pig ears.

    it should be recycled, but "bad-[non-permissible content removed] gas" tanks are not easily visible around these parts.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,488
    Check with your local city dump and see if they can take it.

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  • Peter, I just saw your post. After reading all of the advice, you came onto the key thing. You said it ran for 5 seconds and quit. That is about how much fuel was held in the carb bowl. You have now figured out that you have a clog in the fuel system, so you are almost home free. I would be looking for a screen or filter in the system that could be plugged.

    You did not mention the outside temperture where you are located. Hopefully, it is above freezing. If your fuel tank is empty or close to it, you can collect a bunch of condensation, which can rust fuel screens or freeze. I believe that there is a fuel screen on the intake to the fuel pump.

    When I was learning about bugs, I used a book called "Idiots Guide to VW's" or something to that extent. It was a black and white book, spiral bound manual that was very comprehensive. My ex wife rebuilt her '72 super beetle engine from that book. She was very mechanically inclined, but no VW experience. It ran fine....

    If you got spark at the plugs, it will start if there is something flammable in the carb. My guess is the fuel stopage is the main problem. Don't complicate the problem by introducing other varibles like new wires, etc. It should run with any decent fuel.

    Good luck,
  • thor8thor8 Posts: 303
    I generally use a methodical approach, ruling out the simplest first and moving up.
    The engine needs two things, fuel and fire………… and mechanical integrity.
    Fortunately these old engines are very straightforward. Move from the plugs on up, wires, distributor cap, rotor, points and condenser and finally coil, isn’t that beautiful, there is no more.
    If all checks OK or corrected, you have a spark and does not fire up.
    Compression check, like Mr Shiftright said no compression no detonation. (turning the engine very slowly will give lower values don’t be fooled by it)
    Things to look for if very low, valves easily determined first. Rings second.
    Tank, clean lines, filters, pump, carburetor.
    The reason I mention tank is because fuel in a tank for years will make a beautiful goo, I once left a pickup parked for three years, I finally had to take the tank out, drain the rotten fuel, pour a gallon of Aviation paint stripper, gravel and an assortment of bolts and nuts and between two people shake and shake and shake and at the end never cleaned out, the new gas will dissolve that varnish for ever, I had to put a big inline filter with a clear glass bowl and every few hours would clog up, it was very visible in the glass bowl, but it will give you an idea about the problems it can cause to your fuel system.

    If you have a spark and compression and does not fire you have either too much gas or none. Easiest to check first is assuming you have none, pour a little on the carburetor or use starting fluid, if it fires up for a few seconds and dies you know you have a fuel problem, a carburetor rebuild is on hand regardless.
    With fresh gas on the tank and new filters turn the engine and let it pump some gas into a clear jar to make sure the lines are purged clean.
    There are no more gremlins. Welcome back to the simpler times.
  • swschradswschrad Posts: 2,171
    that's about it, a non-computerized engine's guide to junkyard wars in a couple paragraphs.
  • thanks Thor. I wanted to make sure I rule out all of the easier items before draining and cleaning the tank. I'm now in the process of letting it slowly drain.
  • isellhondasisellhondas Issaquah WashingtonPosts: 19,826
    Can wake up the most stubborn engine! Just don't use too much.
  • ..RATBERT,..replace the filter!! not eliminate it!! was put there for a reason!!...
    ..and,i always ran one of those in line,clear plastic kind, between the fuel pump and the carb..
    itll save ya a carb rebuild in the future...ALSO..the simplest way ta clean a carb on a air cooled is to see if th auto zone's got what they call a carb parts cleaner looks like a gallon paint can full of carb cleaner..(also,might be just the trick ta clean out the tank!!?!!)..take and put the entire carb in that stuff for a few days,making shure to get it into the bowl-try workin the accelerator pump-till it squirts should save ya the couple HUNDRED the bug shop wants for a -o.e.m-replacement.. can check to see if the motor will run by disconnecting the fuel line from the tank at the fuel pump(the line that DOESN'T go to the carb),buy a few feet of fuel line,and drop it down into a gas can of fresh gas..pour about a cap full down the carb,and see if it runs..then decide if th carb needs cleaned..if it runs then,just use the spray carb cleaner..if you use the straw that comes with the cleaner,try spraying some back down the line to clear the clog!!??..might work!!??!
  • nephew's wife has a new aqusition,..
    ..a 1970 vw camper..maybe a westfalla..that's been sitting since nixon was in office,or at least regan..and (oh joy!) i've been drafted as the technical advisor!!..before she bought it from her girlfriend,i told her to be prepared to do the work,as my ability to climb around and under a bus anymore was virtually nonexistant since my back injury.. forewarned fellow air bus VERRY selective who you let know ANYTHING about old buses..or be prepared to "invest" time and effort !!
    ...who out there can let me know where to get a front axle for a -70 bus??..i might have some connections near me here in cincinnasti,but,i thought i'd check here too..i'm shure it'll need other stuff too,i guess i just miss the bug shops i dealt with while i was in l.a.. was gettin starters for $50 bucks,,a tow bar for 35,i get back to ohio,and you'think you were workin on some exotic import!!??!..the starter a friend needed had ta be shipped(two weeks),and went for 200 bucks!!?!plus shipping!..oh well!!..tryin ta save a few bucks!!any guud places on th web y'all herd of??
  • ratbert1ratbert1 Posts: 72
    update. I know it's been a while, but there have been personal reasons.

    I think I will eliminate ONE of the 2 fuel filter. One was added in the engine compartment because the one UNDER the tank was not known. I think 1 filter is enough.

    The carb has been thoroughly cleaned. It needed it.

    I have pulled the fuel tank level transmitter and it looked pretty nasty so I disconnected everything from the tank. This weekend I'll be pulling the tank out and cleaning it. It definitely needs to be done. I would bet that the filter screen is pretty clogged. I have replacement fuel line from the tank to the rigid line that goes under the car and I plan to pressurize the rigid line. That way any bad gas will be pushed out and I know that the line is clear.

    I will also be replacing the fuel lines in the engine compartment. Hopefully the fuel pump is still ok. That would be the only variable left if fuel doesn't get to the carb when I'm done.

    I'm still looking for a good deal on a type-3. :) I'd love to find a notchback!
  • isellhondasisellhondas Issaquah WashingtonPosts: 19,826
    I realize we all have different tastes, but I have never seen the attraction to those. They have primitive fuel injection systems for one thing and as far as looks...well...I just don't get it!

    But...that's me!
  • ratbert1ratbert1 Posts: 72
    I don't know why I like the notch. I don't want to restore one to original - those are kind of ugly to me like that, I think it would look sharp painted in a dark, dark purple with cool wheels and tinted windows.
This discussion has been closed.