9N Success and Surprise

I have been trying to get my 9N running for quite some time now. I know that an engine basically needs only 3 things to run. Fuel, fire and compression. It had been sitting outside for the whole winter. FYI, it now has a nice dry home in a new garage. Pulled it into the garage and tried to start. Only one turn at the most before the battery was dead. Charged battery real good and it turned over slow. Good compression right? Weak starter. Got starter rebuilt since I knew it needed it anyway. Other alternative was 12 volt conversion but I believe Dell in regards to clean, bright and tight. New 00 cables, new 437s, new points and proper gap. Nice blue flame. Still no start but realize I get only a few turns before it seems the starter can't turn it over. Good compression huh! Changed oil and filter. On to fuel. Rebuilt carb. Still no start. Even with starter fluid, not even a pop. Strange. Moved on to verify compression even though I know it is good since it is so tough to turn over. Dug out the compression tester. Pulled all plugs. Put in #1. Turned over. Only 30lbs. #2 is zero. #3 is 60. #4 is zero. Not good! Still very slow to turn over. It should go like crazy without plugs. Something is not right here. 12 volt conversion seeming more justified. Put some oil in each cylinder expecting to free up the rings and valves to get some compression. Let sit for a couple of hours. Tried #1 again. Up to 60lbs. Progress and the engine is turning over better now but still slow. More oil and a couple of hours. #1 now up to 90lbs. Other cylinders coming up nicely too. After 4 rounds of oil and sitting, all up to around 90lbs and the starter is spinning it like crazy. Put the plugs back in, choked it, one hit of the starter and she's running but smoking a lot. Maybe a bit too much oil :) Adjusted carb, smoking stopped by now. Hooked up the brush hog and cut down 3 acres of waist high grass. Dang that was fun. Got lots of thinking done.

What I learned is that you can never tell if you have compression or not without the gauge. After sitting over the winter in the wet outdoors, the cylinders were all mucked up enough to give the impression of compression. Don't be fooled like I was. Use your gauge.

Also, if everything is as it should be, 6 volts is plenty. It turns over nice and fast now and starts with only a brief hit of the starter button.

Robert

P.S. This is the 9N that WillyN rebuilt a few years back.

• My 9N

Good luck,
Dan

Okay, where to start...

First, your 6 volt starter is SUPPOSED to crank slow - so slow even us veterans wonder how the dern things start.

Second, Weak compression is weak compression. Can't SOLVE it by putting oil in the cylinders. All that does is temporarily seal the worn rings which are causing your low compression. Now, it is POSSIBLE that all the comp rings in ALL your cylinders have collapsed and sometimes can be "freed" by putting Rislone or MMO in the cylinders. Perhaps that's what's happening in your case, but from your description I'd be very suspect of those rings.

Ns will run on lower than spec compression which was raised temporarily with the oil you added. I'd continue to check the comp SANS OIL ADDITION to see if you've freed the rings or just Jerry-rigged it to get it running...

I don't know if it was the rings, rust on cylinder walls or valves. What I do know is that the oil reduced a lot of friction that was causing the starter not to be able to turn it over even with no plugs. The friction problem would likely have been rings and cylinder walls. Also, the compression increased gradually over several 'treatments'. That told me something was loosening up rather than the oil just causing a temporary seal on the rings. Since I got zero on a couple of cylinders, I'd think valves were more likely the compression problem rather than rings. I'm not gonna suggest that everything is perfectly fine but I did want to stress to everyone the importance of the compression gauge rather than just thinking it was OK because it sounded and acted like there was compression.

Thanks for your reply.

Robert

While I agrre that a "zero" comp reading is valve-related, the otherwise "immediate" increase in your compression tells me That your rings were stuck too. The oil sealed the rings temporarily until the rings freed up. If your cylinder walls were, as you speculate, rusty and gummed up to the point your engine would barely turn, I really REALLY advise you to watch your compression. It's easy to break a ring and even a piston if you suddenly shock a basically frozen engine.

If a tired engine's been sitting more than a year especially exposed to the weather, it's not a good idea to first inject Rislone or MMO into the cylinders and oil galley, let it sit for a day, then re-inject oil and let sit for another day or two then HAND CRANK her thru several rotations to free everything up. If it turns failry easily, then okay to start. Otherwise, keep the oil up until she does.

I'd also change the pan oil after a few hours and look (with a flashlight) for metal particles in the old oil - indications of broken rings...

And, if you haven't changed out the hydraulic fluid and greased all fittings, it's a good idea...