Not Running tried everything I can think of

[JasonB]

Hello all!

I'm new here and have used the 838 sight extensively to try and figure out what is going on with the A2 that I am working on.

*background*
Father-n-law bought a used A2 that is suppose to have a "rebuilt" engine in it (still need to do a compression check)
Uses it as a run-around for the lease that he is a manager at so it runs/ran off and on for a few days every few weeks and then pretty much 3 weeks at a time (during deer season)
A while back it died and he couldn't get it back up and running. The land owner was currently active so he was able to talk to some of the "motor Pool" guys and told him what to look for. Ie.. Changed the!!
Batteries, coil, condenser, check the carb, and what ever else he "did". It ran for all of 50 hours and died again. While changing out a NOS spare tire I found that pretty much all of the wheels "hubs" were loose and offered to take it to my house in the nice air conditioned garage to fix the hub/bearing.
When there I pulled all of the parts that he had on hand from the stock house that they kept for the A2 and this is what I have done.

*NOW* (last season) oct-dec
New Coil shiny silver one but from NOS supplier from what I am told?, Condenser, points, accelerator diaphragm gas
while replacing all of the parts *thanks you for all of the past post that have been on this web sight* I was able to do all of the things that are common to the A2 for problems.

RAN LIKE NEW!!! for about 2 hours.. While out in the field I noticed that I could start to smell fuel (more then normal it needs a new gas cap gasket) and informed them that I think it was starting to flood. When on the way back, going down a slight incline in 1st gear to avoid the horrendous breaks on this mutt it backfired out of the carb so loud that the two that were in the back thought that my father-n-laws side arm had gone off! And it died...
rolled down the hill where we were able to get it semi sputtering and raced across the field to park it where it has never "run" again.

*NOW NOW*
In the last 2 weeks I have had it delivered to my house where I have.
Full rebuilt the carb 13660B but it has a B-Z spring loaded screw
adjusted the points
Adjusted the valves
changed the fuel pump (the other was bad)
changed the inline "clear" filter
Blown the return line out

Had it running for about 20 min with high idle at one point after adjusting the carb mixture screw parked it and in about 4 min at semi high idle it died from what I'm guessing was a flooding situation because I was running it a little rich.
Parked it and let it cool off (about 5 hours while I was out) to come back and find it wont even try to start.

So back to step 1.
Power to dist. (check)
points (check), Plug gap (check), valve lash (check),
Pull the whole carb apart and break it down all the way to carcass to check rebuild, While doing this I noticed that the fuel/air mixture screw didn't actually seat all the way into the body *finger tight as to not gaul the body* with the spring on so I removed the spring and was able to have the tip of the screw protrude out into the carb. (Only modification that I did here was to but about 1*1/4 winding off of the spring and with just my fingers was able to seat the screw into the body to have the screw fully close off the mixture hole.
Checked the float while reassembling (check)
reinstalled the carb
checked the return line again for blockage
Fully charged the batteries again.

Still not even a hint of fire??

I have no way to set the timing on the A2 that I know of. It has fairly new looking plug Wires on it and I have no spares to "strip" the shielding off of for an induction light.

Just ordered a new coil and plugs from Midwest

Any ideas would be great and if I missed anything let me know?

Again love this sight and all of the resources that it provides to the 151 community


Jason,
Grease and bloody knuckles

[JasonB]

on a side note Hopefully rick and answer this
on my zenith it keeps blowing distorting the diaphragm
I did take some 2000 grit and polish the edges to try and get any burrs off of the body and cap that might not be apparent but I have now gone thru 3 of the diaphragm's trying to figure this one out?

[rickf]

Ok, You got my attention. Kind of, long day. It sounds all the world like a bad coil, when you say NOS shiny one do you mean the one that comes with the mounting kit and has kind of a brushed shiny finish as opposed to a chrome finish? If it is a chrome one then it is one of the bad ones. No matter really, it sounds like all of the symptoms of a bad coil. Have you checked for spark? It will run rich as the spark gets weak. You described the backfire as like a gunshot but said it was through the carb. A backfire through the carb with the air filter hooked up is just about inaudible. Usually a backfire under deceleration is out the exhaust and is the result of unburned fuel lighting off in the exhaust pipe. This is a classic sign of a bad coil or could just be an exhaust leak letting air into the rich mixture with the same end result. Put together with the other symptoms I am leaning towards a bad coil. Now, with all of that said you tell me you are blowing out the accelerator pump diaphragms. A backfire into the carburetor will possibly do that since the pump is vacuum operated and a backfire will put a lot of pressure in that pump cavity. Backfires through the carburetor are caused by one of two main reasons, lean mixture under load and timing too far advanced. Is the timing set right on the line? And if you are using an advance timing light is it set to zero?
With points ignition especially if the switch is left on with the engine not running and the points happen to be closed that is a dead short through the coil, it will not last to long like that. The verdict is still out if the electronic ignition shuts off after a period of no rotation, I have heard both ways but no proof. What I would do is pull all of the plugs so you get decent cranking speed and hook the plugs back to the ire and lay them on the valve cover. Have someone turn on the switch and crank it and watch for spark at the plugs. It needs to be a hot blue spark. If yellow or none then the coil is bad. One thing to check before doing anything though is make sure you are getting 24 volts to the coil terminal. If not check at the wire coming into the distributor. If you have it there then the capacitor at the distributor inlet has gone bad. This very seldom happens but it is something to check just to be sure.

[JasonB]

Rick the coil that I currently have is a shiny one with no markings *hence the new coil already on order*. I'm not sure what I'm getting from Midwest its OEM so its probably the same thing but it did have a little American flag in the corner of the description so I hope that its at least made at home.
Rick thanks for the reply here's what I have so far.

backfire: The backfire with what you have said makes sense with how loud it was (they made my father-n-law get out to prove that he hadn't shot himself) *apparently a 1911 can discharge when not at 1/2 cock. Funny that he didn't know this seeing how he was a gunsmith the last leg of service for the Tx Guard and on the shooting team?

The guys at the motor pool did say that with a carb backfire that it can "blow the diaphragm" but I haven't had any more after the last one.. I'm figuring that the fuel pump went out and that gave us the lean condition, hence the backfire.
I have gone thru 1 more diaphragm after the backfire because the brand new one had a pinhole in it after the backfire, but they are still "breaking down?" where the orange silicone is delaminating off of the diaphragm like its been pinched.
I also have changed the position of the spring for the pump to the outside because the first TM that I had looked at showed it to be on the inside with the diagram. But wasn't able to get the updated info until I came on to 838. Its now installed "correctly" where the diaphragm is facing cup "out" with the spring against the cap.

exhaust leak haven't had a chance to see if there is any leakage in the exhaust but you make a good point about that.. I can see how blending fresh O2 with spent fuel gas will ignite in the pipe causing a backfire.

I don't have a way to check the timing that I know of, Please let me know if there is a way to do it without destroying the plug wires. I only have what is on the A2 and don't want to have to explain why I unshielded a wire so that I could test the timing when the cheapest set I can find is 140$.

24.27volts to coil from coil to plate
not sure if that is telling you anything there because I couldn't find a good procedure to check the dist. wires.. I need to know what wires to check.
When you say "wire coming in" I'm assuming that is the wire that is giving the power to the coil but I can check really quick if you can let me know soon, Ie. its still daylight outside
I was wondering about the capacitor and how to check if it was bad also.. it looks like NOS seeing how the insulation is fraying at the connector but I don't know that I want to mess with it if there is a way to test and see if its still "good".. I'm guessing that the more that I handle it the more insulation will "fall off" and leave expose wire.

[muttguru]

Jason,

I'm not sure how you completed certain carb jobs. This is how they should have been done:-
1. The order of installation of a new diaphragm is crucial to its correct operation. This is how it must be reassembled.



The diaphragm can go either way round BUT ONLY ONE WAY is correct. The centre "cup" disk of the diaphragm must face the spring. The smooth centre disk side faces the carb.

2. How did you set the float level? It should be a gap of 9/32" taken at the tip of one of the float arms.....with the gasket FLAT, as in the photo below.




3. There's a nylon (mylar) tip on the end of the fuel inlet needle (the neeedle that closes when the float rises). If the tip is worn, it can stick in the inlet and cut off the fuel supply. Check its condition.

4. There isn't much point in working on the carb unless:
- the points in the distributor are correctly set;
- the spark plugs are correctly gapped;
- the valve clearances are correctly adjusted;
- the ignition timing has been set.

Ken

[rickf]

As far as setting the timing the easiest thing to do if you do not have an old wire to strip is to acquire a plug wire from any car, preferably an old one that no longer needs the wire. Cut the ends off and strip them back a half inch or so exposing the center conductor and, now this is the hard part so pay CLOSE attention!!!! Jam the end of the wire in the hole in the plug and in the hole in the cap. That will work just fine for setting the timing with a common inductive timing light. REMEMBER! the timing light will be 12 volt!! use a car battery or lawn mower battery to hook the leads of your timing light to or you will be buying a new timing light. Or if you have the battery box cover off of the 151 just hook across ONE battery

[eflexter]

Usually if the timing is off......its off.......and it stays off. If it runs sometimes and other times it doesn't, that sounds like a classic intermittent electrical problem. I'd be checking for spark if I were in your shoes.

It's important to grasp (as Rick said in his post) that it has to be a HOT spark. I have had multiple experiences of being fooled by a WEAK spark which has an orange cast around it and you don't get the nice POP noise when it arcs.

My best test for a true spark is starting fluid. Block or pinch your main fuel line because you don't need any additional fuel flooding the engine. Spray starting fluid inside the carb throat (hold the throttle open while you spray). If you have good spark, SOMETHING will happen. It will either run.....back fire.....or pop out the carb.....but that starting fluid will burn.

If it doesn't pop.....you have a weak spark ( or no spark at all). Weak coil is common. Faulty electronic ignition module is possible. Fouled plugs is common.

[nobby]

Spray some easy start into the carb. If it fires up and runs then the prob is carb/ fuel related.
If it still doesn't fire then its electrical.
at least it will point you in the right direction.

[Emmett]

Not trying to sound stupid here, did you check your oil? If it's overfilled, does it smell like gas?
Had a float stick one time, filled the crankcase with fuel, backfired so strongly it blew the muffler in half.

[JasonB]

Ken: thanks for the reply.. I did do it as the new TM in what you show.. ironically enough it ran great when the diaphragm was switched but then found out that that was the wrong way when it backfired . Never thought of using a small piece of paper to measure the gap just stuck with the old calipers and converted the measurements into a 3point decimal. "did that because on one of the topics Rick or maybe it was you had said that if its adjusted wrong it will not work correctly so I triple checked the measurement.. now I have the "rise" set to the right gap to pretty much .282 on both sides of the "U" like you are measuring.. as for the "drop" or "fall" of the float most have said that there is no "max" so I didn't worry about that as much just made sure that when the float was all of the way down it didn't let the shuttle fall out. I did replace the shuttle and jet for said shuttle because I thought that there might be a chance that it was "hanging" or "sticking" with the soft nylon. as for the rest of the carb, that is one thing that I have experience in doing.. I couldn't find a "master rebuild" for it so I just took it apart piece by piece and replaced every part that I could do.. Only thing I couldn't get out because I didn't want to damage was the "throat choke" and the emulsion tube.. People have said that it was very "fragile" so I didn't do anything to it but make sure that it was varnish free..

I found a Tip from a VW restorer to use a product called "tarn-x" from the cleaning supplies at the local hardware store. "big orange store" and it works GREAT.. its a silver polish and will actually strip the varnish off of the brass while you are spraying it onto the carb.. Did read the directions and It says not to leave it on for more then 2 min. I can see where this might be bad because it starts to "burn" or "re-tarnish" the brass if you leave it in the solution for to long.. I did this because of what Rick has said on a post that there might be something blocking the passages.. also because the VW's carbs are made pretty much out of the same material..

Rick:Thanks for the reply, by saying that you "strip the end off" and "jam it in" I've always assumed that people have meant to jam it in and screw the plug wire back onto the unit. But with what your saying I'm assuming that you are trying to say strip it back and jam it in using the silicone on the "new" stripped wire to hold the wire in place.. In this case I can totally see how that would work for a timing light. Just have to find an old plug wire now. I also knew about the 12v timing light.. I'm a truck driver and have seen many-a-mechanic curse the day when your timing light flashes 1 time like a flashbulb.

Eflexter: Thanks for the reply, I know exactly where you are coming from.. I was taught that there are 2 reasons an old car wont run.. Fire and Fuel.. if you can spray the carb down and get a hiccup then its not fire..
That being said all I have as of now is some brake fluid. I've tried that "with no success" but didn't think to block the fuel line so it might be in excess.. I really need to get me some ether starting fluid.
Funny story, had a friend learn the hard way NOT to look in the carb when running a "shot load", needless to say he was glad he wore a ball cap that day.

Nobby: ^^^ On the same page as ya.

Emmet: Know just where you are coming from with what you are saying.. I changed the fuel pump and that was my first thing to check when I did.. I didn't want to put all of the work into it just to have thinned oil destroy the engine.
I've also seen this happen with diesel cups tearing and pumping fuel into the oil.


Thanks to all who have responded all questions are welcomed!

[JasonB]

Emmet: You got me thinking and I went out side to see what I could find.. Found a faint smell of gas in the oil but level looks good.. Will be changing it out as soon as I get it running.. Probably just as you said washing by the rings.. but better safe then a new engine.

I did try removing fuel line and shooting a bit of cleaner into the intake thru the carb and got zip... zilch... nada... just turn and turn.

so

I checked "just for grins" the connections on the dist.
24v to cap input (cap to breaker plate)
24v from + to breaker plate.. (I'm assuming that means that the cap. is good)
rechecked the ohms to the secondary side to breaker and it was LOW.. I'm guessing that the "coil" is opening up because its 100+ today..

glad I ordered one yesterday!

[rickf]

I am not a big fan of using ether as a diagnostic tool. Like any other gas the proportion of gas to air has to be right or it will not fire. It is great for getting old lawn mowers and big diesels without glow plugs started but I prefer to stay away from it on anything else. The chance for damage outweighs the benefits. Just my personal opinion.

[eflexter]

Rick, I think mechanics have to stick with what works for them, based on their experience. Never be sorry about having a different opinion.

My experience began on the farm trying to get huge diesels started after sitting all winter. Ether was the only way. I use it constantly now to start any vehicle that has been sitting and the fuel in the carb has evaporated. Rather than crank the starter until the battery goes dead. For me it's indispensable.

[rickf]

Carb cleaner is a safer alternative since it is not explosive. Ether can and has caused blown head gaskets and bent rods. And on newer diesels, most of which have some sort of supplementary heater for starting, the explosion can be very violent. I saw a head blown completely off of a 24 valve Cummins.

[JasonB]

well guys still nothing..????
got the new coil.. still a shiny silver one from Midwest
installed new coil
installed new plugs
shot with starter fluid.

Nada. nothing. zip. zilch

removed the plugs from the block and set on top of the valve cover, called my neighbor out to help and not even a warm glow much less a flicker of a spark.

Talked with another "more experienced" mechanic and he said "check the cap. for carbon marks or signs of bulging..
removed the cap. and thing looks all but brand new?

It has a new condenser that I put in last Oct but I'm thinking now that one or the other has gone out??? seeing how I get 24v to the + side of the coil I'm leaning more to the condenser??

Edit update.. just watched a video on my comp and I'm almost sure that its the condenser now.. you can apparently use the Ohm setting on the meter to "charge" the condenser and see a "slow rise".. mine isn't hardly doing a thing. if anything its going down (red to lead, black to chassis) while doing that on my fluke I can see a "continuity bar" and it was jumping all over the place.. so a gentle pull on the lead and it rises.. what I'm finding is that there is probably a broken wire inside of the condenser and when I pull on the lead to "straighten it out" you can see the fluctuation on the meter severely.

any thoughts?