8n won't start after work

[cookesrc]

Hi, first time poster. My '49 8n won't start after doing some work on it. Hope someone can help. Here's the story:

The tractor was burning some oil and had a fair amount of blow by at the fill tube. Also looked like combustion gas was getting into the coolant. Compression was in the high 80's in 3 cylinders, low 80s in #4 (only cylinder that didn't increase with a little oil, looked like exhaust valve leak after inspection). Tractor ran ok but was getting worse under load.
This tractor mostly just pulls a bush hog, so I really didn't want to get into a full rebuild this year. I am aware of the machine work this engine really should have, so please reserve judgement. I pulled the pistons and the sleeves seemed respectable (no scratches), but glazed. Honed the sleeves, replaced rings (gaps are correct). Marked the valves, removed and cleaned them. Valves looked ok. Certainly they would be reground if it were in the machine shop, but in the spirit of this "rebuild" I just lap them. They seat pretty well though.
Reassemble, new gaskets all around, torqued to spec. Now the tractor won't start. It fires a few times like its going to start up, but then just turns over as if it has no spark. But it has strong spark on all 4 cylinders (will jump about a 1/4" gap). There is good fuel flow to the carb, and out of the bowl. I never messed with the carb but the manifold was removed. I've removed the breather tube and after I choke it pretty good trying to start it, fuel runs out of the mouth of the carb. Pulled the plugs and they are all wet. Compression is 110 cold on all 4 cylinders. I can dry off the plugs and leave them out for a bit, and when I try again it will try to fire for a few seconds and give up. Starting fluid has no effect at this point (because plugs are wet?)
FYI its teens and below here in VA right now, but it's always started in the cold with a little effort before. I've got fuel and spark, good compression, and I'm running out of ideas. The manifold looks to have a good seal. What am I missing? Any help is appreciated.

 

[mddorange]

:welcome:
To TBN from Alabama. Is that the gasoline engine or the distillate engine? Did the distributor get tken out or turned?

 

[cookesrc]

:welcome:
To TBN from Alabama. Is that the gasoline engine or the distillate engine? Did the distributor get tken out or turned?

Gas engine, It has the front mount dist which i didn't remove. Didn't remove anything related to timing.

 

[JimRB]

Grabbing at straws.

Check points gap.

Double check valve clearance. Not sure if it is adjustable. Does your engine have the adjustable tappets mentioned in the video? https://www.youtube.com/watch?v=VG0TPXa7SVI


Check that carb is able to shut off fuel at correct fuel level in carb. Too high and it could cause flooding. Does the carb have a fuel cut off valve before the carb? Close it and crank a bit to clear off flooded cylinders.

Try a bit of ether with the fuel cut off closed.

Remove all the spark plugs. Hit them with a lit propane touch to dry them off. Check gap.

For excitement aim the propane touch at the open spark plug holes of a cylinder that has both valves closed. Often you can get the fuel mixture to ignite/burn off. Do not wear plastic clothes when trying this trick. Minor explosions can happen. Probably not a great trick to try on cylinders with open intake valves. If the cylinders are flooding, letting more gas in from the carb is not going to help matters.

Just some things I would be doing. I have done the touch in spark plug holes on my Toyota which had a leaky fuel tank. Cylinders would get wet
with water and not spark off. Lighting off the cylinders with the torch would get it to start. That truck went to the junkyard in the sky after a few years of farm use and starting frustrations. It was not an on the road vehicle.

 

[Eyecatcher]

If you didn't remove the distributor, and you have god fire at the plugs, the points, condenser & coil must be functioning. You certainly have gas at the carb, if it runs out the throat after choking. The plugs being wet indicates that either it's flooding, or not firing at the proper time. Since you had the head off, you had to remove the plug wires. I know they are probably in the metal pipe, so plug end is hard to cross, but check to make sure they are located properly at the dissy end. If they are, it must be flooding. How long did it set with gas in the carb while being repaired? At this point , I would dis-assemble carb and have a look. It doesn't take long for this modern alky/gas to deteriorate.

 

[candoarms]

Did you perform a compression test on each cylinder after you were done rebuilding the engine? Is it possible that you've possibly damaged the head gasket while installing it?

Joel

 

[DJ54]

If the plugs are wet, could be a possibility of over choking..?? Try just a couple of revolutions at full choke, then knock it off, and see if it will fire. You may need to catch it, once it fires/starts choking again at full, or partial, and let it catch it's breath. I'd imagine it will need to run at partial choke, until the manifold warms enough to get good vaporization of fuel.

 

[cookesrc]

If you didn't remove the distributor, and you have god fire at the plugs, the points, condenser & coil must be functioning. You certainly have gas at the carb, if it runs out the throat after choking. The plugs being wet indicates that either it's flooding, or not firing at the proper time. Since you had the head off, you had to remove the plug wires. I know they are probably in the metal pipe, so plug end is hard to cross, but check to make sure they are located properly at the dissy end. If they are, it must be flooding. How long did it set with gas in the carb while being repaired? At this point , I would dis-assemble carb and have a look. It doesn't take long for this modern alky/gas to deteriorate.

The carb sat about 10 days, probably had gas in it. I'll disassemble it as soon as the kit gets here.

Did you perform a compression test on each cylinder after you were done rebuilding the engine? Is it possible that you've possibly damaged the head gasket while installing it?

Joel

110psi on all 4 cylinders now

I'm going to dry it out again and try it with a little ether. It's driving me crazy

 

[Eyecatcher]

Be very careful with the ether, a litle goes a long ways. Before I tried anything else, I would pull the carb, remove the fuel bowl and make sure the float isn't sticking or has a hole in it. Sure sounds like it's flooding.

 

[cookesrc]

So I drained the carb, dried out the plugs and started it on a shot of ether. Sounded good for a few seconds. Tomorrow I'll rebuild the carb and hopefully I'll be sorted out.