I just replaced my solexes with weber carbs this weekend, and I am still having trouble starting. Fuel is definitely getting into the carbs, and the engine is turning over due to the starter. The trouble appears to be electrical. I pulled the distributor wire a little bit out of the cap, and did not see any arcing while trying to start, and there was also no arcing at the coil end of the wire either. The points,and rotor are new, and the distributor cap is in pretty good shape. What should I check next?

Next stop … get fire. To test the coil, insert a plug wire from the distributor into the coil with the plug sitting on top of the valve cover so you can see if it sparks. With the distributor cap off, open and close the points manually; you should see a spark and hear a snap every time you open the points. If you don't get a spark, check voltage on the positive side of the coil. Then check wires, connections at the points for a possible grounded wire. If all of this is OK, try it with the engine turning to open the points and look for spark. When that works, install the rotor, cap and center tap wire and replace the plug wire in the distributor but leave the plug on the valve cover. When turning the engine, you should see spark at the plug. If so, you are done and it should start. If it still doesn't start, try spraying starting fluid down the carburetor. If you have spark, it will start or do something.

Thanks Jim. I've tried the starting fluid in the carbs, so I know I have no fire. When I open and close the points manually, does the key need to be in the ignition in the run position? I am actually a kind of lost when it comes to the coil and distributor... before getting this car I only had a 300CD...no electrical worries. Anyways, without the distributor cap on if you were to open and close the points manually, will you not get one hell of a shock, and how does the coil "know" when you are opening and closing the points? I did just buy a bumch of electrical tools like a multimeter and current/ continuity tester. Is there a good way to use this right now? Which is the positive side of the coil?

You do need to have the key in the "on" position. Did the car run before you put the new Webers on?

Try not to be in electrical contact with the coil or plugs or points - not dangerous (unless you have a pacemaker, maybe), but for most folks, it's not a very pleasant experience. You should get a spart at the points if you open and then close them.

Thanks guys!
Bill, the car was not starting when I changed the carbs, but I thought it was because I accidentally left the key in the ignition over night. Now I realize that I must have burned something out. Okay, I just went outside and tried two things. First I used a light bulb current sensor between the positive side of the coil and the engine block, and it lit up with the key in the on position. Then I tried to manually get a spark by putting the center wire if the distributor cap to the engine block (still connected to the coil) and opening and closing the points. No spark. What does that mean, a bad coil?

I broke out the multimeter. It should 12.14V at the positive side of the coil and continuity with the engine block at the negative side. Then I tested the distributr cap and it showed coninuity at each side fo terminals. When I tested the spark plug wires... none of them showed continuity. I can't explain why..it doesn't make sense, but I am going to go pick up some new spark plug wires now.

Okay, new coil, new spark plugs, new spark plug wires to accompany my new weber carburetors and new air filters. And the darn thing won't start!!! There was an electrical problem but I think I fixed it. The engine seems to want to start, especially when I pump the gas; it occasionally sounds like it might but then it doesn't. Starting fluid does help it along briefly, but it doesn't catch. What should I try next?? The webers came prejetted, but there weren't any instructions that came with it, so I just bolted it on as I thought it should go. I took a guess about how the linkage should be...when I press the accelerator, the throttle levers do go down in unison (not all the way down, but mostly). Do I need to adjust the idle mixture and other screws? How do I know which screws do what? Like I said, there are no instructions. Ugghhh...this is frustrating!

Hemant …. Lots of things going on. Try to focus on one at a time. Don't worry about the carburetor adjustments until it actually runs. Focus on the electrical system until you can see spark at a spark plug. Do not worry about not getting connectivity through your plug wires with your multi-meter; the wires have very high resistance to elimate radio interference. Back to trouble shooting … connect the multi-meter to negative side of the coil and ground. When you open and close the points the circuit should open and close. You should see the same open and close on the meter when you turn the engine over with the starter. If you do not get this open and close connectivity, you installed the points incorrectly, one of the connectors is probably touching ground or you are missing an insulator washer on an electrical connector. When you get this working, then check the coil with a plug wire from the coil to a plug on the valve cover, key on, open and close the points and you should see spark. After this works, reinstall the rotor, distributor cap, plug wires and center coil wire and with the plug on the valve cover, check that you have spark to the plug when the engine is turned over.

At this point, it should couch, sputter or do something or we need to do some more checking. Again, focus on electrical until it works correctly.

Thanks Jim
After getting the new coil, the electrical side seems to be okay. With the spark plugs taped to the top of the engine block, I could see them firing in order as I turned the engine. I put them back in and tried to start the engine. It almost runs if I pump the accelerator pedal. I sprayed some starting fluid onto the air filters and that seemed to help a little bit. I think I am almost there. Where do I go from here??

Next step, get the timing close. Do you have a timing light? I'll assume not; Bill Streep, chime in if I say anything incorrect. The object is to get the spark plug to spark at the correct time. Since it "tries to start", it is close. On the driver's side front of the engine, there is a metal pointer next to the crankshaft pulley. There are marks on the pulley; TD, 10, 20, 30 and 40 to indicate Top Dead center, 10 degrees rotation etc. With the car in 4th gear, rock the car forward to turn the engine until 20 is opposite the pointer while the numbers are counting down. Now do the spark plug on the valve cover again with the plug wire to the coil. Loosen the bolt at the base of the distributor so that you can rotate it. Turn the key on and rotate the distributor back and forth until you see a spark. You want to stop rotating the distributor while it is being rotated counter clockwise and at the point of the spark. Tighten the distributor bolt; replace the spark plug, wire and center wire. The timing is now set to 20 degrees before top dead center in a static condition. Bill or Arthur check my direction and static setting.

Also check the carburetor idle jet adjustments. The four adjustment screws on the base of the carburetor where it joins the manifold should be adjusted to one and a half turns.

Try to start it again and see if we made any progress.

Jim,

Good explanation. Since I haven't had a problem starting mine in a while, I can't remember the static setting, but I'll check it in a little while. I always set my timing to between 35-38 degrees at 3000 rpms (or higher).

I might suggest an easier way to check the timing.

Rig a wire from the small terminal on the starter long enough to reach the battery. Pull spark plug #1 and touch the wire to the positive terminal on the battery while watching the pulley as described as the engine turns over. Make sure that the 20 degree mark is aligned with the engine on the compression stroke. You can either look at the cam lobes for #1 to make sure they are closed, or listen or feel for the compression.

At this point, the rotor should be pointing at the #1 wire. If it is close, you should turn the distributor until #1 fires. If it is 'way off, you may have to re-position the distributor.

BTW -Is gas getting to the carbs? No problems with pump or filters?

My $.02.

Thanks Jim and Bill.
I don't have a timing light, and I have no problem picking one up on the way home from work if it helps--but you guys may have to guide me in using it. My car is parked in my driveway which is pretty steep and the front wheels have sunk into the mud, so rocking the car forward is nearly impossible. What about jacking up the rear of the car and turning the rear wheels instead? I can't wait to try this... my roommmate almost bought a timing light yesterday because he wanted to learn to set the timing in his '66 mustang. Is there anything else I may need from the autoparts store on the way home?

The timing light is all that you will need. The objective of rocking it was to turn the engine; you may be able to do that by turning the fan while keeping the fan belt tight. If you have a 22mm socket(?) or a US socket that will fit the bolt in the center of the crankshaft, you can turn the engine that way. If you get a timing light, that might be easier. Buy a timing light with an "inductive" pickup.

Attach the red and black clips of the light to the battery and the "pickup" to the first plug wire (forward). With the light trigger pulled, the light should flash as the engine is turned over. Aim the light at the timing mark on the front of the engine, with the engine turning over, the flash of the light should "freeze" the timing mark so you can read it. Rotate the distributor until it "freezes" at about 20.

Adjust the carburetor idle jets and it might run.

Good Luck.

I'll bet you that your problem is a short between the points and the wire to the coil. If your distributor is new, check where the wire goes through the distributor to make sure it has the proper insulating washers.

If you were getting spark and fuel your car would make an effort to start. The timing wouldn't be all that far off since the distributor is indexed.

If everything was removed from the car and your timing is way off and the car won't start, you can follow this procedure to make sure its all set up correctly:
I call this the toilet paper job, and it never fails!

With the spark plugs out turn the engine with a wrench (gearbox in neutral) and have your friend put his thumb over the spark plug hole on the #1 cyl to check for pressure. When he gets pressure then you know the enging is coming up on the compression stroke in that cylinder. Then watch the timing mark and set the engine to the correct static timing. (Jim or Bill or ?? what is the right number?) When you have the engine at the right point, then you can set the points. Loosen the distributor clamp so that the distributor turns freely in place. Then turn it so the points are closed. Take a piece of toilet paper and carefully pry the points open and slip the paper in between and let go. Now hold onto the paper being careful not to tear it...just pull gently and turn the distributor slowly around. When the points just barely begin to open the paper will slide out. This is where your spark will occur. Now put on your rotor and look where it is pointing. Make sure that corresponds to the wire on the cap going to the #1 cylinder. Check the remaining wires to make sure they go to the correct plugs according to the firing order.

Give everything a once over and before starting the car. It should start. Once your car is running you can check the timing and set it again for full advance while running if you prefer.

Good luck!
Eric

I've found that my preference on turning the engine is to block the right rear wheel front and back, put it in 4th gear, and jack up the left rear. With the parking brake off, have someone turn the tire. Removing plugs makes precision work a little easier.

I just got back from vacation, and started working on the 190SL again. Here's my current status... I found the pulley and got a 22mm wrench to turn the engine by hand. For some reason the pointer that points to the numbers on the pulley is missing. I looked at a friend's '61 190sl and he has one, so I know where it is supposed to be. So I roughly set the engine to 20 with the numbers counting down (clockwise) and then taped spark plug wire to the engine block. I turned the distributor counterclockwise til I got a spark, and then locked it into place. Then I connected the other spark plug wires to the spark plugs in this order 1-3-4-2 going clockwise and tried to start it. It didn't start, but it backfired through the carbs. What does that mean? What should I try next?
By the way, I have no ballast resistor on the new coil (which is an MSD Blaster 2-- I assumed there was already an external one since the old dead coil needed one as well), and I have a new Crane fireball 3000 in the box that I am waiting to install after I get the car running. Am I better of trying to get it working with the Crane Fireball in place?

[Edited by hgupta on 04-21-2001 at 05:20 PM]

Backfiring through the carb generally means that the engine is firing with the intake valve open, which means that the timing is too far advanced. Mark the current position of the distributor. Retard the timing a slight amount and see if there is any improvement. If there is, go a little more until it starts.

Backfiring through the carb can also be caused by a too tight intake valve adjustment.

Don't put it at 20 where you think the pointer is.
Put it at zero.
Then pop the dist cap and turn the dist til the rotor lines up with the #1 plug wire tower.
That should be close enough for start.

I went out and bought a compression guage. I put the guage in spark plug hole number 1, and turned the engine until the guage showed the slightest bit of pressure. I turned the engine a little bit further until the timing pointer was approximately 20...the rotor was now pointing in the opposite direction of where it was before. Then I did the spark plug thing that Jim Villers recommended , and the engine almost started! So I think I have the timing very close! So now I am a little lost...do I want to set it to zero as Arthur recommended or to 20?

Zero is TDC [ top dead center]
That means the piston is all the way up and ready to be ignited. 20 is advanced and not good for starting.

Remember , this is a four stroke engine. That means the
timing can be 180 degrees off at the rotor. That is what you have noticed. That is why you have to bring the piston up on the COMPRESSION stroke when you are setting the pointer position. When you have TDC on compression stroke and rotor facing #1 plug wire, you are READY TO START.
Otherwise , you can be on the exhaust stroke--no good.
I think you have it now.

This applies to most any 4 cycle engine

Woohoo! It started! With the pointer at 20 (If I had a pointer) it starts, and I can rev the engine upto 3000 RPM (I didn't try further). At zero it backfires through the carb, but these are just rough estimates for the timing. Even though it starts, there are 2 problems that I encountered. First the engine didn't idle when I left off the accerator pedal, it just slowed down and stopped. Second, after it stopped, there was a some smoke (exhaust?) coming out of the carburetors. What does that mean?
Is there a good way to adjust the timing without a pointer?

[Edited by hgupta on 04-21-2001 at 11:21 PM]

The more I think about it, the madder I get! Why would the previous owner take off the timing pointer? It makes no sense! Well, I ordered a new one, and so I will have to wait until Tuesday to try to get this thing running. Do install the Crane Fireball, do you have to recheck the timing? Should I go ahead and install it while waiting to get my pointer?

Great job Hem ant .... Nothing feels better than success. As a next step, I am in the keep it simple camp. One thing at a time. Now that it will start, check a few things: Does it have oil pressure? Keep it running a while to see if the thermostat opens and the cooling system works and you are leaking water. Is the generator working, ignition light off? Check for oil and fuel leaks. Listen for noises that don't sound right. Delay the Crane ignition until everything else is adjusted and it starts consistently.

Without a timing pointer, you can still do a lot. If you have a timing light, check to see that the timing varies when the engine is revved (shows that the ignition advance is working). You can do a "quick and dirty" timing setting by revving the engine over 3000 RPM (when the advance is finished advancing) and set the 30 to 40 where you think the pointer should be. This should be close enough. Next adjust the idle speed screws (next to the throttle) so that the engine idles or at least doesn't stall.

Check is for vacuum leaks. With the engine "idling", spray propane (unscrew the tip from a propane torch) around your intake manifold gaskets and listen for changes in engine speed. A change in Ram's indicates the location of a vacuum leak (it is sucking something other than air through a crack and this changes the engine RPM). I use propane but carburetor cleaner or brake cleaner should also work (thought I have never tried it). Intake manifold leaks are very common in 190SL. If you still think that you have a vacuum leak, disconnect and plug the hose to the brake booster (at the rear of the engine).

Again .. good work.

Thanks Jim,
I'll check each one of those items and report back. What about the smoke coming out the carbs after the engine shuts down? Is that just cause the carbs are new or because the timing is off? It scares me to run it like that.

The "smoke" you are seeing is gasoline vapors. I think that this is "normal" for a side draft carburator. Mine does it when I have the air horn off. The vapors should not cause a problem but your carburators should not drip fuel. If they do, you should investigate it before proceeding. While I have never had a fire, I do keep a fire extingusher near each door. Always think safety first; an accident can ruin your whole day.

Please don't take Jim's thoughts about intake leaks lightly. My opinion is that this is the single biggest problem with keeping these cars running right. The side draft carbs hang off of the intakes, and bounce up and down wearing the aluminum intakes. If your car is like most, the carb support from the engine to the front carb is missing. I use just plain old water to check for vacuum leaks - anything of these suggestions will show a change in rpms, which indicates a vacuum leak. If you have one, let us know, and we'll tell you how to remedy it.

As for the carbs, Robby has the best idea on balancing them. Balance them at WIDE OPEN rather than at idle stop. (make sure that they both hit the wide open stop at the same time). If you got yours with the factory recommendations, the should run at least ok, so I wouldn't worry about what jets, etc. you have.

Once you get it running, you can adjust the idle mixture screws. This assumes you don't have an intake vacuum leak! With the engine hot, AND the carbs balanced like above, adjust your idle speed screws so that they both just touch the stop. You should idle at 1300rpms or less. Mine idles at about 1000 - many won't idle below 1300 (the book says 1300). If you are over 1300 rpms, you can't properly adjust the mixture. Remove the linkages from the carbs - your idle speed adjustment should keep it running. Put a digital tach on the ignition (you can use your ear if you have to, but it's not very accurate). Now you can adjust each of the 4 idle mixture screws. Be careful, don't screw them down hard or you can ruin the carb by cracking the little hole in the carb that the screw goes into. Starting at one end, turn the screw in until you either hit the bottom, or the engine speed decreases (you are looking for a change in rpm of 1 or 3 or so). If nothing changes, screw it out until it drops. You will likely have it speed up slightly, and then go down. You are looking for the leanest mixture (screwed in) that gives you the highest rpms. Now go on to the next one. You may have to go through this a few times with each one in turn to get it right.

Let us know how you do.

Okay, my timing pointer still hasn't come in yet. I hate how a much needed part takes forever to arrive, but someting like a horn button arrives next day. Anyways, I did check out all the things that Jim and Bill recommended, and everything seems fine. I found out that the source of the smoke was not my carbs but was leaves that had stuck to the manifold! My linkages are kind of loose, so I am going to try to make a nicer one. I was able to redo my linkages so that they are tighter, and set the timing to something like 35 at 3000 RPM. I don't know what is up with my timing light, but it doesn't seem to freeze the numbers very well--the numbers seem to jump around. Besides having a crappy timing light, an even worse tach, and no pointer, the car seems to like where I set it. (I had to mark "35" on the pulley with white out to see it clearly--that's the last time I buy cheap tools off of ebay!). Then we were able to get the idle down to about 1500. I still need a carb sync tool, so there's not a whole lot of precision stuff I can do.
The good news is that I did drive the car around the block, and wow what a difference! It surprised me when it peeled out when I first hit the gas. The old solex carbs needed full throttle to even get the car moving! I did notice that the coil was getting really real hot, and there seemed to be some sparking going on near the distributor cap at the wire that attatches to the points. Hmmm....is it time to drop in the crane?

I'd blow off the carb synching tool. Seriously. I have one, and I NEVER use it. I really like Robby's method - make sure they both hit the wide open stops at the same time.

My timing light was a cheapo from Western Auto/Parts America. Works fine. I use a piece of chalk on the end of a dowel to mark my timing, but I like your whiteout idea... You could also be experiencing some electrical problems - As I recollect, you have new wires, rotor, cap. Were the wires good ones, or cheapos? Seems to me if the car will get rubber, it's running pretty well??

I don't know if I've ever felt my coil before. If you have the Crane ignition, and the car is running well, I'll pop the sucker on and see if it runs better. It's pretty easy to do...

No intake leak? None? Wow, I wish I was so lucky...

yeah, the wires were cheapos...well $20 for the set even though they are 7.5 mm and supposedly silicon insulated. The bosch ones were $45 but not in stock, and the MSD ones were $75 plus $12 for the crimping tool and had to be custom cut. The good thing about the custom ones is that they will fit back in the wire holder and look a lot nicer. Right now I have wires running all over the place. I may get a set of them, but I didn't want to blow all my money in one place.
By intake leak, you mean right where the carbs bolt on, right? I used new gaskets with some sealant that my mechanic gave me... I think it was called something like Indian seal. He told me not to bolt the carbs in so tight that they cut into the seal, so maybe that helps as well. There wasn't a leak when I first checked it, but it hadn't been run much yet. I'm crossing my fingers hoping that one won't appear.

No, the leaks will show up between the head and the intake manifold, not the intake manifold and the carbs (although that will happen also...). The intake manifolds are aluminum, and the exhaust manifolds are cast iron. The "wobbling" of the carbs causes the intakes to bounce up and down wearing the tops and bottoms. Try spraying carb fluid or water between the manifolds and the head when the engine is hot and running. If you get a change in rpms, you have a leak. Can't balance the carbs with a leak... Oh, and NO amount of gunk will fix it. Been there, tried that. If you have an intake leak, let us know...

Bill ... Permatex #2 (non-hardening type) liberally spread around the manifold joint will work but is very "tacky". I ran that way for a number of years. You still need the carburetor support (I use two, one for each carburetor).