New guy with 1950 DeSoto - starting issue

[Joe48]

I have to hold my foot on the gas pedal and hold it to the floor to start the engine there doesn't seem to be any flooding, there's no smell of gas or sign of any running down the carburetor. Sometimes after I first start it up and

let it warm up I can restart by not even touching the gas and just hitting the starter botton, I assume this means the ignition system and timing are set and working properly.

[Young Ed]

I have to hold my foot on the gas pedal and hold it to the floor to start the engine there doesn't seem to be any flooding, there's no smell of gas or sign of any running down the carburetor. Sometimes after I first start it up and

let it warm up I can restart by not even touching the gas and just hitting the starter botton, I assume this means the ignition system and timing are set and working properly.

When its warm I always start mine without touching the gas.

[Lumpy]

Have you tried a little starting fluid? No...have not re-read the whole thing.

 

Edit: okay, I read the whole thing...again. I hear a lot of "at the right time" concerning the spark. I will beg to differ, if the spark plug fires when the piston is on the intake stroke, you will get a bang out of the carb. If it fires on the exhaust stroke, which is pushing unburned fuel out of the cylinder, you'll get a bang out of the exhaust.

 

It might not start, but if there is spark and compression, you'll get some popping, or banging, or the engine will kick-back...no matter what plug wire goes to what plug, or if the timing is 180 degrees off, or 30 degrees, or 270, or whatever.

 

I hope you have pulled the carb, and are just trying to start with starting fluid, until you get some kind of reaction out of the engine.

 

Now I know that really doesn't help, but I have to ask again, are the plugs sparking under compression? On motorcycles, I have experienced spark plugs that sparked when out of the engine, but not when in it. Or perhaps the spark was like ten times as weak when in the engine. I don't know. I had an AJS that could eat a plug in one week.

 

Also, I'm sure you are using new plugs, but they could be fouled and dead from all the gas and oil, might want to get a new set, and just use them with starting fluid, and no oil down the cylinders, and no carb. I've had good luck cleaning spark plugs with carb cleaner, but in this case I'd get a new set.

 

Anyhow, good luck, we are pulling, hoping for you, but it's sure becoming a mystery.

 

k.

Edited June 24, 2014 by Lumpy

[Jeff Balazs]

Lumpy;

I had already suggested this a while back. It is just a hunch but I would have to say that it sure seems as if the spark is breaking down as you have suggested. This is not something usually associated with a low compression engine like this but I suppose if the coil was real marginal it could happen. Just because they fire when out of the engine doesn't mean they will when in place.

 

I still have an old AJS that can eat a plug in no time at all..... but it is a very high compression two stroke with an original stator ignition.

 

Jeff

[Lumpy]

Yes, I can't shake the idea that if there is spark, and any compression at all, and you give it a shot of starting fluid, something is going to pop or bang, or the engine will kick back or something...no matter where the timing is set, or which wires go to what plugs. If not, it's hard to believe there is fire in the hole. All the gas that's poured into the chambers, and all the oil squirted in...I'd say start fresh with a fresh set of plugs, take that $&&$ carb off the manifold, and turn it over with a few shots of starting fluid directly into the intake manifold.

 

Wow, I'm not familiar with two-stroke AJS's. I had a '52 500 single for many years. Now I have a Yamaha TT500 that I painted green camo, and then put AJS stickers on it, because nobody knows what an AJS is. !! It likes to have a nice fresh plug in it, if you don't like kicking a 500 single over lots of times before it starts. Once it starts, there's nowhere it can't go. !!!

 

k.

[Joe48]

I have to hold my foot on the gas pedal and hold it to the floor to start the engine there doesn't seem to be any flooding, there's no smell of gas or sign of any running down the carburetor. Sometimes after I first start it up and

let it warm up I can restart by not even touching the gas and just hitting the starter botton, I assume this means the ignition system and timing are set and working properly.

[Jeff Balazs]

Yes, I can't shake the idea that if there is spark, and any compression at all, and you give it a shot of starting fluid, something is going to pop or bang, or the engine will kick back or something...no matter where the timing is set, or which wires go to what plugs. If not, it's hard to believe there is fire in the hole. All the gas that's poured into the chambers, and all the oil squirted in...I'd say start fresh with a fresh set of plugs, take that $&&$ carb off the manifold, and turn it over with a few shots of starting fluid directly into the intake manifold.

 

Wow, I'm not familiar with two-stroke AJS's. I had a '52 500 single for many years. Now I have a Yamaha TT500 that I painted green camo, and then put AJS stickers on it, because nobody knows what an AJS is. !! It likes to have a nice fresh plug in it, if you don't like kicking a 500 single over lots of times before it starts. Once it starts, there's nowhere it can't go. !!!

 

k.

I don't see any need to take the carb off. If there is an actual spark happening "around" the correct time.... then ether should get a reaction. May not start but it should at least make some noise like it is trying to.

 

Lumpy we got way off topic....... I have a 49 AJS 500 single and a 74 250 AJS Stormer. The Stormers were MXers and off road bikes made by Norton- Villiers. Has a variant of the famous Starmaker 2 stroke. I have owned it from new and used it as a desert racer.

Good thing you are on this side of the pond..... I know folks in the UK that would have you drawn and quartered for putting an AJS sticker on a Yamaha.   Heck now that I think about it I may just have to give them your name and collect the bounty.

 

There are some interesting similarities between the story of Chrysler and Associated Motorcycles that produced AJS and Matchless M/C's among many marques. They were both the smallest of a Big 3 and each had a long tradition of engineering firsts. Owner Charlie Colliers won the very first IOM TT in 1907 and was a huge proponent of endurance and race testing. And just like we see certain Mopar products pull down huge $ at car auctions today you will also see AJS racing bikes hitting astronomical $ at M/C auctions.

 

Jeff

[Lumpy]

My reasoning to take the carb off is to eliminate pouring anymore gas into the cylinders, until the problem is resolved. Ensure the plugs (new ones) remain clean and dry. Once he gets a reaction, a kick back, a pop, or a bang, then put the carb back on and try to start it. If the timing is correct, then the engine will even run for a few seconds. Then go back to flooding the thing out. ?? Right at the moment, I think the carb is just kind of "fouling" things up. "It's not helping!" As the wife would say.

 

Oh but the AJS stickers on my TT500 are in HONOR of my old AJS. !!! And AJS in general. They should give me the bounty in appreciation. Yes the history of AJS is interesting, and they built some far out, ahead of their time engines...much like Chrysler. I'd love to have another one, maybe that's what I'll find in a barn someday, and I'll get it for $50.00. But probably not. Also looking for a flathead BMW basket case, for around $100.

 

ken.

[jeffsunzeri]

 

I have to hold my foot on the gas pedal and hold it to the floor to start the engine there doesn't seem to be any flooding, there's no smell of gas or sign of any running down the carburetor. Sometimes after I first start it up and

let it warm up I can restart by not even touching the gas and just hitting the starter botton, I assume this means the ignition system and timing are set and working properly.

 

No.

It would indicate that the timing is OK, but there are some components in the ignition system that are heat-sensitive when in marginal condition.

[knuckleharley]

Lumpy;

I had already suggested this a while back. It is just a hunch but I would have to say that it sure seems as if the spark is breaking down as you have suggested. This is not something usually associated with a low compression engine like this

Jeff

I experienced this years ago with a 10 HP Briggs and Stratton riding mower engine. Damn thing nearbout drove me crazy before I figured out compression was killing the spark. This was with a Champion spark plug.

 

I also had this problem with Champion spark plugs in a stock 53 Mercury flathead V-8. For reasons I never did figure out,it would kill at least 3 Champion spark plugs in a very short time.  I went through this twice and then switched to either AC or Autolite plugs,and never had a problem with it again.

 

If everything else checks out and you still can't figure it out,replace all the plugs with new Autolite or AC plugs and see what happens.

[Joe48]

I'm going thru the whole ignition system again, put in a new set of Autolite Plugs and maybe see if I need to replace the coil or the wires going to it. Let you all know in a couple of days how it went.

[Jeff Balazs]

I experienced this years ago with a 10 HP Briggs and Stratton riding mower engine. Damn thing nearbout drove me crazy before I figured out compression was killing the spark. This was with a Champion spark plug.

 

I also had this problem with Champion spark plugs in a stock 53 Mercury flathead V-8. For reasons I never did figure out,it would kill at least 3 Champion spark plugs in a very short time.  I went through this twice and then switched to either AC or Autolite plugs,and never had a problem with it again.

 

If everything else checks out and you still can't figure it out,replace all the plugs with new Autolite or AC plugs and see what happens.

I have run across enough problems with Champion plugs over the years that I do not trust them at all.  EVER.

 

That said the OP's problem may not actually be a problem with the plugs at all. I think it is more likely it is either the coil or some other component in the ignition system...maybe a combination of things...and/or a timing problem. Any chance a badly worn timing chain may be contributing to the problem? I never hear anyone talking about this but my otherwise fairly fresh rebuilt engine had a pretty sloppy timing chain in it. Mine had sat for years and when I pulled the head and oil pan it was obvious that it had very low mileage on a rebuild. But when I pulled the timing cover the story was a bit different. Just another idea.....

 

Jeff

[Don Coatney]

This thread has been unsolved for a long time. So I will tell my story from earlier today. My car had been running really good until I went for a drive yesterday. My engine developed a slight irregular misfire with no repeatable pattern. I suspected an issue with adjustment of my dual point setup so the first thing I did was pull my distributor. I set up my bench test using an electric drill, power supply, and test coil. I found a slight variation in dwell angle. I made a very slight adjustment in point gap and corrected that issue. Upon reassembly I discovered what I believe was the real problem. A cold solder joint on the power supply wire from the coil to the distributor as pictured below. I made this cold solder joint recently but I used my small solder gun and not my big iron. So I made up a new wire and corrected that problem.

 

Prior to pulling the distributor I brought the engine to TDC and noted the rotor position. Having made the slight point adjustment and correcting the cold solder joint I re-installed the distributor and positioned it very close to the same position it was in when I removed it. I made an attempt to fire the engine and it was a no go. I made attempts to fire the engine with my remote starter button and a hot wire under the hood while turning the distributor under the hood and it was all a no go. I connected my timing light while cranking the engine with the starter and found my timing was a good way off from TDC. So I brought the engine to TDC using the starter motor. I pulled the plug wire from #1 spark plug and connected it to a spare plug sitting on the head. I then (without spinning the engine) moved the powered up distributor until I was getting spark exactly at TDC correctly static timing the engine.

 

As I had been spinning the engine a lot with no fire I suspected my plugs may be fowled so I removed them and sand blasted them. While the plugs were out I also used an air gun down the plug holes to clear the cylinders of any flooding. Reinstalled the plugs, hit the starter button, and the engine fired right up. I then used my timing light to dial it in.

 

So my point being correct engine timing is a very small window. If you take the time to insure your engine is correctly static timed and all other system problems are corrected the chance of starting is greatly improved.

 

 

 

 

 

[Jeff Balazs]

Very nicely put Don.

My own observations on my engine is that is around an 8 degree window  (4BTDC to 4ATDC) and anything beyond that makes for hard or at least harder starting. As this has been my first experience with a Mopar L6 it took me a while to come to grips with this. I suppose because it is in such a soft state of tune I was expecting it to be more tolerant of how the timing was set. Actually nothing could have been further from the truth. This window could vary some from engine to engine but it really isn't going to be by all that much.

 

Jeff

[Lumpy]

I was wondering if the flathead's chamber shape, and flame front, and all those strange and different flathead characteristics make it more sensitive, but my flathead motorcycle's engine really tolerates a lot of variation in the timing, and will usually start regardless of where the timing is, within reason...but probably more like a 20 degree "window" or more. Way too early and it will kick back, and of course ping badly under load, but otherwise fires up way advanced, or way retarded. ?? You really have to experiment with it to find the sweet spot...setting it "by the book" does not always work well.

 

k.

[Niel Hoback]

That's pretty much how mine acts. Whenever I have the dizzy out for some reason, I stick it back in about where I think it was, and crank on it for a few seconds. If it kicks back, I know to retard it about a half inch and it will usually fire and run so I can get a light on it and do it right.  If it spins over easy and doesn't fire, I know to advance it about a half inch and it will fire up for me.  Its pretty flexible about timing, I think about 10 degrees either way, which is quite a big window.  

   You know, that's kind of why I like these old mopars, they aren't real particular, don't complain much, and go along way on a few bucks.  My dad taught me that 55 years ago. Its still true.

[Joe48]

Well here's the latest, I went through everything in the ignition new plugs, wiring connections, timming, etc. Then after taking it out driving and reaching full 180+ engine temp. I turned the engine off and it would start right up again, but if I let it sit a half hour or so while still warm it still doesn't want to start. I then have to give it several 10+ second long attempts cranking the starter over while holding the gas pedal to the floor while the engine struggles to fire up and start but eventually does then runs just fine.

[greg g]

adjust your float so that there will be less gas in the float bowl.

[T120]

Read through this topic today and there has been a lot of helpful information passed along and apart from the
engine being tired I'm surprised with a good battery it hasn't at least had an encouraging sputter.The lack of
good compression(rings,valves or both)sounds troubling-resulting in loss of vacuum(suction) pulling in proper fuel/air
mixture.I have nothing to add.I normally would not recommend starting fluid but it has been suggested...
(The mention of AJS Matchless 500 singles brought back fond memories and I would certainly welcome the opportunity to make room in my garage for one).

Edited July 7, 2014 by Ralph D25cpe

[Lumpy]

I agree, starting fluid is kind of a last resort...and in this case the last resort was way back there on page two or three!!! But...where's Wilf?

 

k.

Edited July 7, 2014 by Lumpy

[soth122003]

Joe48,

 

Greg is right. I had to lower my float to avoid that problem. initial setting is 5/64". set mine a 7/64".

Also, instead of holding the pedal to the floor, pump the pedal about 3 times. This will work the accelerator pump to put in 3 squirts of gas instead of one by holding the pedal down.

[T120]

I guess I got off track reading through this topic (thinking about motorcycles)  - didn't realize we hadn't heard from Wilf in a while... 

As I understand it, an engine should pull min 3 inches of manifold vacuum at cranking speed...

[bbbbbb99]

This thread has been unsolved for a long time. So I will tell my story from earlier today. My car had been running really good until I went for a drive yesterday. My engine developed a slight irregular misfire with no repeatable pattern. I suspected an issue with adjustment of my dual point setup so the first thing I did was pull my distributor. I set up my bench test using an electric drill, power supply, and test coil. I found a slight variation in dwell angle. I made a very slight adjustment in point gap and corrected that issue. Upon reassembly I discovered what I believe was the real problem. A cold solder joint on the power supply wire from the coil to the distributor as pictured below. I made this cold solder joint recently but I used my small solder gun and not my big iron. So I made up a new wire and corrected that problem.

 

Prior to pulling the distributor I brought the engine to TDC and noted the rotor position. Having made the slight point adjustment and correcting the cold solder joint I re-installed the distributor and positioned it very close to the same position it was in when I removed it. I made an attempt to fire the engine and it was a no go. I made attempts to fire the engine with my remote starter button and a hot wire under the hood while turning the distributor under the hood and it was all a no go. I connected my timing light while cranking the engine with the starter and found my timing was a good way off from TDC. So I brought the engine to TDC using the starter motor. I pulled the plug wire from #1 spark plug and connected it to a spare plug sitting on the head. I then (without spinning the engine) moved the powered up distributor until I was getting spark exactly at TDC correctly static timing the engine.

 

As I had been spinning the engine a lot with no fire I suspected my plugs may be fowled so I removed them and sand blasted them. While the plugs were out I also used an air gun down the plug holes to clear the cylinders of any flooding. Reinstalled the plugs, hit the starter button, and the engine fired right up. I then used my timing light to dial it in.

 

So my point being correct engine timing is a very small window. If you take the time to insure your engine is correctly static timed and all other system problems are corrected the chance of starting is greatly improved.

 

 

 

 

 

Something like this was my first thought

[Jeff Balazs]

Just a guess.....but he was sounding fairly frustrated. Maybe he is just taking a break before he tackles it again?

 

Ralph......you ought to keep an eye open for an AJS or Matchless. They are out there......just sort of depends on what you want. A buddy of mine wanted a restored one several years ago. He got a pretty nice Matchy from Oz via Ebay. Nice solid complete runner for a decent price. I built mine the hard way......bits and pieces. Started with an engine out of a attic in Iowa. I built mine as a period desert sled. Gathered the parts from all over the world. Took a year and a half but it was really fun and I still have friends all over the place. In my opinion the ones built in the late 40's and early 50's are the sweetest runners. The later bikes have higher compression and lighter flywheels.......they make more power but are not as forgiving to ride.

 

Jeff

[Wilf DeSoto]

I've been busy with a lot of things, so sorry for the late reply. I cannot login on every device I have. I have since my last post also tried new spark plugs, other coils, different timings. Still nothing. Somebody is going to help me though, so maybe I will get it up and running soon again.