800 Ford won't stay running more than a few secounds

[jaxs]

My question; is there a way to tell for certain wherther problem is with fuel or is it with spark? I have owned propane tractors of all colors for over 50 years and worked on this type ignition even longer. I know my way around a vom so I have never thrown many electrical or ignition parts at problems before. To save a few of the reccomendations,I've listed what I have done.
The facts;
800 Ford on propane, owned 20 years,not using oil,was starting,running and idleing perfect until faltering for a few seconds like it was running out of fuel then ran fine for 30 minutes while completing task. Started and ran fine for 10 minutes next day then sputtered for 10 seconds then fine for 15 minutes. Two days later,started and emediatly sputtered 5 seconds then died. I tested primary pressure on Impco model J regulator and drew a bubble on secoundary outlet. Set a full grill bottle on ground next to tractor with new model J and new hose to carb. Did-assembled carb,inspected and cleaned. Checked intake gaskets,tried wiggleing distributor parts for wear. Repeated the start,sputter 5 seconds then die behavior two dozen times over the next two days while I replaced coil,points,condenser,wire from coil to points,insulator where 12v wire enter's distributor,dist cap,rotor button,plug and coil wires,primary conductor to points,spark plugs. Spraying starting fluid and squirting gas into carb intake as it sputter's make's no difference. It start's and run's about the same with a plug wire on old plug grounded to block. It look's like plug sparks right up to the last gasp. There's been a Battery Minder on it the whole time but the theory of starter depriving ignition isn't vailid here anyway because it die's after starter is no longer operating. I've already stooped to throwing parts at it and would at minium like to determine wherether it's fuel or fire before replacing parts second time. Any known trick to eliminate fuel or ignition from the equation?

 

[super55]

This is an interesting problem you have. Sounds like you have already done a large part diagnosis and replacement of typical parts.

Only thing I can think of is to go and put a timing light on it. If if your having spark all the way through and it didn't keep running when you shot ether or gas in the carb throat when it ways dying out it would lead me to check out the timing on the tractor. Could possibly have a stretched timing chain or a worn distributor thats throwing your spark off causing it die out.

 

[jaxs]

I will put a light on it. I skipped past timeing because my light has been loaned out for 3 years:smiley_aafz:and A. I didn't think timeing would come and go like the first couple of times it faltered,and B. I figured if timeing was close enough to start,it would be close enough to run,at least until put under load. I did check compression when changing plugs (148 to 152) which I thought ruled out broken/skipped teeth on cam-crank. Pulling front cover to look at match marks on gears will be the last thing to happen unless someone convince's me it's possible with symptoms at hand. In the old days every mechanic used an oscilloscope when ignition problems were suspected. I called around to borrow one but everyone is using scanners and I don't see an obd port on my tractor:confused3:. Just for grins,I turned gasoline off on my MF-65,ran it out of fuel then sprayed starting fluid into air intake. It hardly fired. Neighbor claim's starting fluid isn't what it used to be. Have ya'll noticed a difference in s.fluids?

 

[super55]

Oscilloscopes are about as common as dwell meters now.

The only reason I bring up the timing chain, cam and distributor is because I just recently had an old 67 ford pickup that I had to send to the shop because the thing would run fine until you shut it off than you couldn't get it started no matter what for about until it sat for an hour or two. I was wholly convinced the thing was carb related. Went and put a new carb on it, re-routed lines to ensure no vapor lock etc. Ended up being the distributor and cam were severely worn and timing gear was missing two teeth. Thing was jumping timing all over the place. As long as it was running it wasn't an issue but the vehicle would not restart for anything.

You might want to go check out ytmag forum. It's a tractor forum that focuses on old iron tractors and there are some really info on it. Some of the people on there were service mechanics for brands no longer around. They can probably give you some better advice than I can.

 

[Soundguy]

the best way to test spark on an old ford.... isn't with any meter.. it's with it's own spark plugs!!

never guess about spark. if she stalls, pull a plug and roll her over and see if the plug is hitting. if yes, double check other plugs. if yes.. it AIN'T spark.

Also.. if it has spark and makes NO pops, AND the valves are moving.. then it is not getting any fuel.

 

[jaxs]

You might want to go check out ytmag forum. It's a tractor forum that focuses on old iron tractors and there are some really info on it. Some of the people on there were service mechanics for brands no longer around. They can probably give you me better advice than I can.

I thought I'd touch base to let you know I didn't just wander off and abandon my post. I'm still trying to recover my timeing light. Meanwhile I looked up the ytmag forum, searched archives then lurked a while. Interesting group that undoubtedly have a fine time but I didn't even sign up to pose my question. The forum is set up similar to this and others I've visited but the members don't follow rules very well. Eventhough there's a rural living forum,it sit's quit while regulars use technical forums gossiping about pet peeves,how many possums were caught in the chicken coop last night,health issues,current events and such. That wouldn't matter except new posts don't bump thread back to the top and new threads are shortly buried unless retired mechanic visits real often. God bless the admins for allowing it because as I said,they do injoy themselves and that's a good thing. I'll check in with update when I recover my light.

 

[pmsmechanic]

This sounds like an interesting thread. I'll say something if I have something useful to say. In the meantime I might just learn something.

After thinking about the situation as described my thoughts are that it's fuel. The time of starting is always the hardest on a coil. If there's any weakness in the ignition it usually shows up then. Your tractor starts. It just won't keep running. I would be tempted to take the intake hose off and add a bit of propane from a soldering torch and see if it keeps running. Just an idea.

 

[Soundguy]

This is an interesting problem you have. Sounds like you have already done a large part diagnosis and replacement of typical parts.

Only thing I can think of is to go and put a timing light on it. If if your having spark all the way through and it didn't keep running when you shot ether or gas in the carb throat when it ways dying out it would lead me to check out the timing on the tractor. Could possibly have a stretched timing chain or a worn distributor thats throwing your spark off causing it die out.

I guarantee you that no ford red tiger engine HAS EVER had a stretched timing chain.. ever...

 

[Soundguy]

I thought I'd touch base to let you know I didn't just wander off and abandon my post. I'm still trying to recover my timeing light. Meanwhile I looked up the ytmag forum, searched archives then lurked a while. Interesting group that undoubtedly have a fine time but I didn't even sign up to pose my question. The forum is set up similar to this and others I've visited but the members don't follow rules very well. Eventhough there's a rural living forum,it sit's quit while regulars use technical forums gossiping about pet peeves,how many possums were caught in the chicken coop last night,health issues,current events and such. That wouldn't matter except new posts don't bump thread back to the top and new threads are shortly buried unless retired mechanic visits real often. God bless the admins for allowing it because as I said,they do injoy themselves and that's a good thing. I'll check in with update when I recover my light.

you must not have hit the ford forum.. it is generally filled with tech questions and answers. only an isolated OT post or two.

 

[jaxs]

The jury came in today and all is back to normal. Everything on tractor was fine all along,,,,except alternator. When I finally got my old school tools back and hooked light up,it went crazy then finally burned out. After some voltage readings,I realized something wasn't right with battery voltage while engine was running. Alternator is putting out high voltage alternating current. Disconnected alternator and she ran like her old self. Best I can figure,here's what was happening. Since everything was in order as far as fuel,ignition,compression and such,when engine was cranked over it fired and began running. As engine began running,alternator begain kicking out alternating current. Alternating current connected to a transformer will cause transformer to put out voltage eventhough there's no make and break like there is with points opening and closeing. Not only was the coil fireing in sync with points,it also fired at same frequency as alternating current,voltage was stepped up considerably and undoubtedly jumping wires. All that stray sparking probably amounted to world's worst case of pre-detonation so engine died. I'm so happy to have it up and running I just might take it to the atv mud pits and show the kids how it's done. Might even wash it afterwards and drive it to church Sunday.