No start

[Gramps in NM]

Stuck for sure. 1951 8N sidemount, 12V
Within last few months have installed new plugs, plug wires, points, rotor, condenser, dizzy cap, replaced wiring.
STEPS TAKEN
engine turns over well, enough to pull back starter
tractor in heated garage
keeping battery fully charged
Items checked, gap on plugs/points
points opening/closing properly
Good strong spark from plugs jump 5/16
fuel flow strong--drained and replaced fuel
firing order 1243
new gaskets on intake/exhaust manifold
rotor aligned with #1 plug wire when 0 degrees on flywheel
checked linkage, as should be
replaced carb with new one, tried various points on set screws, fuel runs from air inlet if choked just a little.
placed hand over air inlet on carb, have suctiuon
Checked compression, all 4 over 90 at 6500 feet
After numerous tries engine does not fire, but plugs are not wet. have cleaned plugs and retried, no start.
tried starter fluid, did not fire off or even give a good chug.
tractor was plowing snow and starting to run rough, with severe pause when initially accelerated. would then run strong at higher RPM.
First thought was carb, hence the new one as I knew the old was going fast downhill. Have also tried the old carb again without sucess.

WHAT have I MISSED?
Thanks and all suggestions welcome.

 

[LeoinMI]

Just a guess here.There may be moisture in the distributor if you were plowing snow with it. Or,..condensation can form in the distributor or in the gas tank.(Moving the tractor from a heated space out into the cold and back into a heated space again).

 

[GRAY WHISKERS]

Try a shot of starting fluid in each spark plug hole. You will have to work fast. But if you don't get a pop. Then you diff. have problems. I have a couple spark inducaters i hook up to make sure I have spark. I don't trust just one wire for a check.

 

[Anonymous-0]

if the plugs are dry, it can be only a few things. you have a vacuum leak somewhere in your intake or not enough compression in the engine. try squirting a little motor oil in each spark plug hole and turning it over a bit. then dump a little gas down each spark plug hole, then fire it up. if it starts, you know it has to be one of those. if it doesnt.......timing is off maybe?

 

[Dell (WA)]

Gramps.......you write......"tractor was plowing snow and starting to run rough, with severe pause when initially accelerated. would then run strong at higher RPM".......sounds like you had CARB FREEZING. internal ice clogging the mixing jet causing ruff running and then with higher RPM's running off'n the mainjet for strong running.

Carb FREEZING is a know phenomium due to certain climatic conditions. Infact lite airplane have a "CARB HEAT" control that is pulled during landing so you don't loose engine power. Loosing engine power can ruin yer day, eh?

You write......"After numerous tries engine does not fire, but plugs are not wet. have cleaned plugs and retried, no start. tried starter fluid, did not fire off or even give a good chug".......didja know that you can putt'chur 5-nipple capple 180* outta and you will gitt plenty of bluefire sparkies but won't start nuttin'.

You write......"replaced carb with new one, tried various points on set screws, fuel runs from air inlet if choked just a little".......didja know most carbs don't have their setscrews adjusted correctly? Assuming you have a M/S carb, adjust the side-pointing idlemix to 1/2-turn and the down-pointing mainjet to 2-turns. That should gitt'cha started.

And surprizingly enuff, iff'n you "overchoke" yer carb, guess what? itt'll LEAK outta the mouth. DO NOT CHOKE until after 2-rumpas and then only a QUICK PULL on the knobby. After engine starts, you can "feather" yer choke (about 1/4") for warm-up.

Try those and report back........Dell

 

[nobo]

rotor should be at number 1 at 4 degres before tdc on compression stroke

 

[Gramps in NM]

Thanks to all of you for your inputs. Almost all of your suggestions had been considered/tried. Late yesterday after having replaced the fuel h from a fresh plastic jug (bought two days prior) I climbed up into the seat and gave her a go. Away went Molly, ran a little rough at first with high RPM. All my prior attemps at starting had been from the floor, not from the seat. Believe the solution came from new fuel (that moisture thing) AND sitting on the seat depressing the clutch gave the engine a little boost. Might be someting to remember when advising on difficult starting, get in the seat and push that clutch in.
Now I just have that very fast idle to contend with.
Thanks everyone

 

[JMOR]

(quoted from post at 11:06:31 01/17/11) Thanks to all of you for your inputs. Almost all of your suggestions had been considered/tried. Late yesterday after having replaced the fuel h from a fresh plastic jug (bought two days prior) I climbed up into the seat and gave her a go. Away went Molly, ran a little rough at first with high RPM. All my prior attemps at starting had been from the floor, not from the seat. Believe the solution came from new fuel (that moisture thing) AND sitting on the seat depressing the clutch gave the engine a little boost. Might be someting to remember when advising on difficult starting, get in the seat and push that clutch in.
Now I just have that very fast idle to contend with.
Thanks everyone

olly just need to feel the warmth of Gramp's backside in her seat! :lol: