Enginge won't start, need ideas to try

[Esgbradford]

Hi guys. It's been a while since I posted. Since then, I rebuilt and polished my A4's Carbureator, serviced the fuel pump, and installed a new fuel filter, new fuel hoses, new fuel fittings. I assembled everything, and tried to start the engine. No luck. Now, before you start getting ideas, I'll tell you what all has been tried, and the results.

So, according the the Moyer manual, there must be three things present for the A4 to start: Spark, Compression, and Air-Fuel mixture. When I assembled the carb, I took care to check gaps, etc, when rebuilding and installing.

I manually used the mechanical fuel pump to pull the fuel from the tank, through the new filter and hoses to the pump, so we know the fuel pump works.

When attempting to start the engine, we get good turn-over, and the sound seems to me that it is trying to fire. However, the enginge doesn't "catch". I adjusted choke and throttle, no luck.

First I suspected electrical. I pulled the plugs (have about 2 hours of use on them, perhaps less) and inspected. Two plugs had dry carbon , 2 had wet carbon -- makes sense since 2 cylinders would have been in either compression or intake mode. The carbon tells me that the fuel mixture is burning, were just not getting a clean burn. In fact, once when opening a plug, the mixture had burnt, but not been exhausted yet, and black smoke rose out of the spark plug hole.

I pulled a plug wire put it on a screwdriver, and turned the engine over with the screw driver about 1/4 inch from the block, the spark did jump the gap. I pulled a plug and grounded the plug and viewed the spark action. It was a good, white-blue spark.

So, then I suspected that we weren't getting proper fuel, I used di-ethyl ether with propane and butane starting fluid. It still did not start. This should eliminate carbeuration and/or fuel from being the cause of the problem, I would guess.

It was beginning to look like a compression issue. So, I returned the next day with a compression tester. I tested each cylinder 1-4: 115, 110, 115, 105. Which should be fine for a engine designed to be 95 or higher. One thing did happen though on one cylinder, it received a single reading of 150 eventhough the rest were 115. I think this means that the burn from one cylinder made it into the one being tested via intake or exhaust manifold. This may imply a stucky valve -- but the rest of the readings were good. But anyway, we do know that the engine has compression.

So I thought, maybe we have plug #1 identified wrong on the distributor(though the engine did work before the carb rebuild). I verified that the #1 plug was leading to the location on the distributor cap as previously identified by the Piston #1 TDC method. I double checked by rotating the plugs 90 degrees in each direction. Neither attempts did not even try to catch, so we can conclude that the #1 cable is in the right place. I then verified that the plugs were oriented 1-2-4-3 in a clockwise direction on the distributor. I then opened the distributor and looked at the rotor and disty cap. Both are in like-new condition (having less than 2 hours on them). There was no water or oil in or on the cap.

So, I thought that perhaps the timing was off, and the plugs were firing too late, and the pistor was already moving away from the flame before the gas burned. This could look like lack of compression, and cause carbon fouling. So, I advanced the timing a bit. Still would not start.

I did not try retarding the timing.

The fuel is old, but it didn't start with Ether, so it is unlikely that the fuel is the issue.

Did not check spark plug gap, points gap, etc. But since we were getting good spark and were jumping a quarter inch, then it doesn't seem like the electrical system is bad. Hmmm... Come to think of it, I only tested the spark on one wire, so it is possible that only one (or two) pistons are firing. However the carbon on each plug infers that all pistons are firing, without power.

I did not replace anything in the electrical system; it didn't seem necessary due to healthy spark.

So, I can't think of anything else to try other than the just start guessing and replacing things until I accidentally stumble on a working combination.

Thought. I had to manufacture a jet for the carbeurator. If the hole were too big, could it make too rich a mixture such that adding ether to the mix still wouldn't work? If so, then I should shut down the fuel pump (or disconnect it from the carb) and try starting it with just ether.

Any other ideas?

Oh yeah, I already tried drinking a beer, yelling at it, being nice to it, coaxing it, and threatening it. Nothing seems to work.

[Marian Claire]

Plugged exhaust??? Dan S/V Marian Claire

[ndutton]

Please confirm and report back:

1. Raw water intake valve is closed during all this cranking. Any chance the cylinder with 150 compression was #4?
2. Why the need to manufacture a jet?
3. Confirm gasoline in the carburetor bowl. There's a removable plug on the bottom.
4. Confirm the choke is closing completely.
5. Was the distributor ever removed during this work?

[lat 64]

Originally Posted by Marian Claire

Plugged exhaust??? Dan S/V Marian Claire

+1
My very thoughts.

I think you probably know this, but I'll put it up just for completeness sake:

the choke plate needs to be completely closed and the throttle has to be set about half way open to even get it to fire on most tries. Even when warm, it needs throttle. Only rarely does mine fire without throttle when restarting warm.

A very good post, by the way,
Russ

[TomG]

Sounds like a plugged exhaust to me too. And I should know. Can you seperate the hot section at the flange where it exits the exhaust manifold and give her a try?

[Mo]

Check that spark plug wires are going to right plugs. I remember someone having pics of the distributor....but if my tiny little mind is working (looking in over engine with flywheel forward) the one at the 9 o'clock position on the distributor is number one. Number 2 next going clockwise as you look at it as noted above...and so on to 4. It is very easy to make mistakes on the plug wires so start looking for simple things first.

If you have not move the points just run the cover of a cigarette pack through them to clean. If you have move them they will have to be re gapped. Sounds like it is trying to start.

[tenders]

Your comment about the burn-yet-incomplete burn is interesting. You've tried 90 and 270 - now try rotating those plug wires 180 degrees from where they're supposed to be and see what happens. You have nothing to lose and this fixed the symptoms I once had like yours: my distributor was somehow long-ago installed 180 degrees out of sync and I hadn't marked the wires when I took them off...and why should I? I had the Moyer book showing how it was supposed to be done sitting right next to me....!

(I have since concluded that the engine rebuilder, not Moyer, may have put the distributor in backwards in an effort to be helpful as the engine has a V-drive and is installed 180 degrees opposite from the usual way.)

Are you getting any backfiring? I was, once in a while. If you don't think you're getting backfiring, you aren't - it's scary.

-> Agreed, excellent post, you seem very methodical.

[JOHN COOKSON]

Originally Posted by Esgbradford

Hi guys. When attempting to start the engine, we get good turn-over, and the sound seems to me that it is [U]trying to fire. [/U]However, the enginge doesn't "catch". I adjusted choke and throttle, no luck.

This is what my A4 was sounding like when the choke was not closing all the way.
The movable arm on the choke needs to be free to swing through its entire arc and not hit the fixed arm, engine bed, or anything else or the choke will not close all the way.
Sometimes it's necessary to increase the angle between the fixed and movable arms so the movable arm has room to swing through its entire arc.

TRUE GRIT

[Esgbradford]

Hello all. Thanks for the input. I would have never thought to check if the exhaust was blocked. I like that idea, give me hope. I will try it on Saturday, and report back.

Instead of loosening anything to allow free exhaust, I think I may just take a long tube and pump out the water from the muffler. That should unplug the exhaust. That's the first thing I'll try.

If the engine still doesn't start, then I'll do ther other things, such as turning the wires 180 degrees, or check for fuel in the bowl.

I doubt that 180 degree wire rotation would be the solutuion since I determined the location of #1 by the thumb test TDC method. I'm thinking the fuel bowl idea isn't the problem -- if it were, the engine should have started with the ether. I'm pretty sure the choke does close all the way, but I'll try it and check it with a feeler guage.

Not sure about backfiring. I didn't hear any backfiring. I did see a few moments of gas being expelled from the tube above the flame suppressor. Would that be backfire? The piston with the 150 number, I'm pretty sure was #1 or 2. But I'm forgetting which now. Only happened once.

I know the spark plug wires are in order, but I didn't test them all. They were new last year. The distributor was not removed. The points were not moved.

All in all, I'm going to put plugged exhaust at the top of the list. That is a really good idea.

By the way, the reason why I needed to manufacture a jet is because I opened and inspected the carbureator, and all was looking good except for one mangled jet -- looks like a previous owner had recently rebuild the carb, and tried to remove the jet, but stripped it, and left it in there. I used a screw extractor to remove the jet.
I tried to buy another one, but found out that that particular jet isn't sold separately. So, I measured the threads and size of the screw, and measured the depth and widths of the holes, and then very carefully, with wire guage drill bits, drilled a brass screw to match. I think it's a piece of artwork, that little jet I made. It may not work... but I'm proud of it.

I'll let you all know what works and what doesn't.

Thanks,

Eric

[lat 64]

Originally Posted by Esgbradford

....I did see a few moments of gas being expelled from the tube above the flame suppressor. Would that be backfire?...

Huh?

If there was gas(gasoline) coming from crankcase vent, the rubber tube above the flame arrester, then I think something is amiss.

Can you give a better account of this particular symptom?
Was it really gas or some unidentified liquid?
Either way, it seems odd. There should be just vapors coming from there, and mostly invisible.

Russ

[Sony2000]

See if it runs with half a teaspoon of gas poured into each cylinder. Be ready to try an keep it running.

[sastanley]

Eric, I have a couple comments...

Put away the ether. It doesn't solve anything except burn too hot and damage the motor. There is a reason its nickname is 'motor crack'.

You can visually check the choke..simply loosen the screw that clamps the flame arrestor to the carb and remove the flame arrestor. Pull the choke cable and stick your finger in the carb..if the choke is fully closed you will not be able to move the butterfly...if there is any play in the choke with the cable all the way out, it needs adjustment. The most common problem I've seen here is the choke armature bumps into the choke cable sheath before closing fully.

As for the carb drain..why not take a second and drain it while you are checking the choke? Any crud laying in the bottom of the fuel bowl should get flushed out.

If the exhaust is plugged, it could be from a number of factors...most common is the build-up of scale and raw water deposits right at the point where the water is injected into the exhaust hose between the muffler & the hot section. Most people have a mixing 'tee' of sorts. You will need to pull that area of the exhaust apart to clean it out.

[JOHN COOKSON]

Originally Posted by Esgbradford

Not sure about backfiring. I didn't hear any backfiring. I did see a few moments of gas being expelled from the tube above the flame suppressor. Would that be backfire? The piston with the 150 number, I'm pretty sure was #1 or 2. But I'm forgetting which now. Only happened once.
Eric

I don't know how gasoline would come out of the slash tube if there was gasoline in the oil, but anyway check the oil for gasoline just for peace of mind.

TRUE GRIT

[Esgbradford]

I'm sorry for the confusion. By gas, I meant not liquid or solid. I probably should have Said vapor. Anyway. I found the obstruction to the exhaust. I am so embarrassed, that i don't want to say what it was.

[ILikeRust]

You're among friends. And besides, confession is good for the soul.

[ILikeRust]

We will, however, reserve the right to bust your chops mercilessly about it for years to come.

Just ask me about spark timing...

... or oil gallery plugs ...

[Esgbradford]

Okay, so i opened the ball valve on the exhaust. Seems like the exhaust is no longer blocked. Hahahaha...

I also checked the spark plug gap and wire order and position #1. The motor now tries such harder to start. The cylinders are really trying in succession. But now the vapor coming out of the crank case vent is more often and is white/blue smoke which disipates rather quickly. Could this indicate a blown gasket? I'll capture a video, and then find out how to post it.

BTW, the choke is fully closed.

Eric

[ILikeRust]

Originally Posted by Esgbradford

Okay, so i opened the ball valve on the exhaust. Seems like the exhaust is no longer blocked. Hahahaha...

There's a ball valve on the exhaust? Is that to keep the sea out of the engine when anchored or moored? Interesting.

Originally Posted by Esgbradford

The cylinders are really trying in succession. But now the vapor coming out of the crank case vent is more often and is white/blue smoke which disipates rather quickly. Could this indicate a blown gasket?

I'm thinking at this point, it might be flooded, after all your unsuccessful tries to start. Also possibly timing - you might want to start at square one to make sure your timing is on. Find top dead center of the ignition cycle on cylinder 1 and make sure the distributor is pointing at the right place.

[lat 64]

Confessing on the internet, that takes a real man!

I think Dan gets the award on this oneThe first one to post the right diagnosis gets a free pound of compost worms from my personal herd. You pay shipping—UPS ground of course.
Sounds like the rings are stuck or worn out. Time for MMO and/or saving pennies for the overhaul. I bet you can keep it running for this season anyway.

Cheers,
Russ

[smosher]

Actually, everyone does interesting things on Occasion and if you did it, probably means someone else has either done the same or will do the same.

By stating what you found would help future A fourians from making the same
mistake.

Everybody has done it, I've done my share thats for sure, just find my posts.

Steve

[Mo]

Good show Eric. Once spent the better part of a day troubleshooting the engine running poorly. I'd put new plugs in about 2 weeks earlier and overlooked them time and time again, unable to find the cause of the miss I finally checked the plugs...it was a plug problem....and I did post my short-coming. As stated by the guys, that's how we learn.

[sailshigh]

End of season and start of season I put Marvel Mystery Oil in my cylanders. It always seems to keep the compression up and I have used it for over 20 years. It may help with your issue, but no guarentee...Good Luck!

[Esgbradford]

I work in IT support. One of the things I find myself telling people at times is just because you found a cause of a problem, doesn't mean that there isn't a second cause too. Looks like I found the second cause of my engine's woes (and am working on the third).

Many people on this board have indicated that the correct position of wire #1 on the distributor is at 9:00, as looking at the engine from the fly wheel. I had previously used the thumb-blow-off test to find the position #1 on my distributor, which was at 6:00 -- much to some people's disbelief. So, since I was adjusting the disty to see if a few degrees would allow my engine to run, I decided to rotate the disty 90 degrees clockwise, which would in theory put position #1 at 9:00 instead of 6:00. I had to then move the wires too, to match length of wires. Then I tried it again. Boy did it ever try to catch. It seems that a previous owner had moved the distributor for one reason or another. The interesting thing was that it really did run, before, with the disty turned 90 degrees to 6:00.

Anyway, the engine did catch a few times, and started to get the RPMs up, but then it slowly dropped RPMs, and died. It did this several times. Each time, I could feel my heart lifting with hopes that the problem had been resolved. But dash it all, the engine quit and I was crushed each time.

So, problem #1 was the Exhaust valve was closed.
Problem #2 was the distributor position.
Problem #3 is the dying of the engine, and the general lack of power. I suspect that may just be old gas. I'll pull most of the old gas out and put some new gas in there. Any other suggestions?

Thanks, as always, for your suggestions.

Eric

[Esgbradford]

Originally Posted by sailshigh

End of season and start of season I put Marvel Mystery Oil in my cylanders. It always seems to keep the compression up and I have used it for over 20 years. It may help with your issue, but no guarentee...Good Luck!

Thanks for the suggestion, I did that too. I put about 1/4th ounce, a little less than a tablespoon in each cylinder, then with the plugs out and the gas off, I turned the engine over a few times, to ensure spreading on the walls. It splattered out of the holes...

Eric

[Carl-T705]

Eric, took measurements and came up with a replacement carb jet...... I like your style!!!!! Now get every bit of that old gas out and get some fresh stuff in there. I doubt you have any serious problems, good compression eliminates ring problems. You've got spark, if the timing was drastically off you would get backfiring either at the intake or exhaust. (If the gas is good). Did the problem start after working on the engine or just after the Winter layup?? I would remove the water feed for the exhaust and blow air through the exhaust to be sure it is clear. You can remove the sparkplugs and check for air escaping there as well. Or have someone put their hand over the exhaust when cranking the engine to see if they can feel air escaping. This may sound a little crazy but check that you have good voltage at the battery when engaging the starter and at the coil.