At wits end trying to start 8n

I find that I seem to get such high compression--that's not the right word, I know--that gas vapor will blow out the air intake where it attaches to the carb, when I'm trying to start the engine. (I haven't a clue how to describe/identify why it is that gas vapor should blow out the air/intake and carb gaskets (pre-re-tightened) when I try to start the engine. Seemed at one point to come out around the governor housing, too.)

Some more facts, narrated out of order. 1. I get good spark to cylinders 1 and 2. Weaker spark to 3 and 4. I'll replace two wires on Monday, though it seems improbable that two wires in a new set would be bad. (I put in a new distributor/coil/wires/spark plugs last season: gapped spark plugs and have verified accuracy of setting. (Spark plugs do get very black quickly: too rich a mixture?) 2. The carb floods very quickly. 3. When the engine was running last week, the air intake would "make a gulping sound." Now I seem to get very poor air draw. I took off the oil bath: got slightly better draw, but still not what it was nor is it satisfactory. 4. I cleaned EVERY filter in the fuel line, including the wire mesh at the fuel line elbow (into the carb.). Put in clean fuel. 5. Again, when trying to start tractor, I get TOO MUCH FUEL as it runs out the needle and air intake connection (pre-re-tightened). Have tried to start tractor on dry carb, gradually allowing fuel to spill into carb, to find some happy moment between starving/drowning. Cannot find that point. 6. Have taken off the distributor and coil, to let them air dry: no discernible condensation. The rotor will only fit on the shaft in one way, so I think timing is not an issue. (Dumb inference?) 7.1. Took the entire carb off, blew it out, hoping that since I do not have a tune-up kit--not one available nearby--running air through the thing would take out that single piece of dirt/gunk which keeps motor from starting. Replaced carb, no difference at all: not even with two Hail Mary's and three Our Father's. Also, crossed self: no effect. 7.2. Seems that the float in the carb. is solid, and does not, in fact, fill up with gas: also, is one-quarter inch from surface, all the way to the hinge. (I was thinking the float allows too much gas into the carb. That hunch may still be right?) 8. Came into house to find revolver for tractor, but have cooled off.

So: engine is very, very close to turning over. I get the occasional backfire. But the engine will NOT turn over. Carb floods, and I pull the choke wide open. Still, just lots of whirring and near starting. Perhaps the problem is electrical after all? Ideas???? jim.

(Please do not tell anyone about this.)
Thanks to all for the advice.

jim

Here's a simple test if you can shut off fuel flow to the carb: Make sure it is not still flooded. Crank with throttle & choke wide open & no fuel flow to clear the flooded carb. Then spray WD-40 into the carb while someone cranks it. If ignition is good, it should fire (WD-40 is a good substitute for starter fluid). If it fires, it ain't electrical. And if it fires, it will probably run for a couple seconds, further confirmation it isn't an electrical problem.

However, note that if it does not fire, that does NOT necessarily mean that it IS an ignition problem. Could be valves, compression, etc.

No one has addressed your "gulping sound", but that does not sound like an ignition problem either. Considering the poor air draw & this gulping sound, if the WD-40 doesn't make it fire, I would do a compression check for step 2.

What has changed since last week when it last ran? Has it been left out in the rain? If so, maybe it is ignition after all--check distributor cap for any hard to see lines like little, tiny hard to see cracks or tracks indicating cross firing. If the cap is damp on the inside, the current will follow the path of least resistance and a plug in a cylinder under compression has more resistance than one which is not. This would explain your backfiring, but it doesn't explain the flooding.

Good luck & keep us posted. I spent 2 days out in the field last week trying to bleed my Yanmar's non-standard fuel system so I understand your frustration.

You write..... .."2. The carb floods very quickly. "..... ..while flooding carb is most likely caused by yer heavy-handed choking technique, or could be caused by sticking float valve, but it is a very likely candidate for NON-floating float. The float occasionally developes pin-hole leaks in solder seam. SINK yer float in GLASS JAR of HOT WATER and watch for tiny stream of bubbles being forced out.

You write..... .."3. When the engine was running last week, the air intake would "make a gulping sound." Now I seem to get very poor air draw"..... .almost sounds like you have a "stuck" intake valve. When an intake valve sticks open, you ain't gonnna gitt much "suck". Suck (vacuum) is needed to gitt the fuel/air mixture into the engine. Iff'n engine don't gitt fuel/air, it ain't gonnna run even iff'n carb is flooding. Does that surprize you?..... ....respectfully, Dell

Jim.

• OH SNAP!!!

This really all sounds like a number of issues but it can be tied to a tired engine that is low on compression. Try jumping it with 12 volts directly to the starter and see if it will fire off. Don"t jump to the battery! Make sure you have it in nuetral.

My engine is low on compression and can be a real trick to start sometimes and mimicks the symptoms that you are describing. I use a combination of low throttle settings and choking which I think increases the velocity of the air passing through the carb and better atomizes the fuel.

Soundguy

The puking back out of the carburetor point to:

1.) Firing order wrong.

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2.) Burned or stuck valve. (Do a compression check.)

3.) Some of these engines had a fiber timing gear that would tear loose from it's hub and/or lose teeth, causing the camshaft and distributor to get "out of time" with the crankshaft, or not turn at all..

jim.