Break'n her in

[FMPreacher]

9N / 12 volt / front mnt dist. / fresh eng.
Well got the old N's engine rebuilt and running finally. What's your valued opinon on how to break it in properly? I've done a 2 mile test drive up and down the road. And somehow it's developed some trash in the main main jet(I Think). Somehow between a good sediment bowl, new inline filter, & new strainer elbow on the carb. Headed to the shop to fix that in a little bit. She only runs good above a idle if you hold the choke out a little. I'm guessing something inside the carb is flaking off???(who knows) God Bless You and Your "N"

 

[Bruce (VA)]

"She only runs good above a idle if you hold the choke out a little."

Pulling out the choke gives you a richer mixture. So, you could have either a fuel or spark problem.

A carb out of adjustment will also cause this problem; set the main jet at 1-1/2 turns out & leave it alone.

A dirty carb can cause the problem as well; start by cleaning the fuel screens.

Dirty/old gas, or water in the gas can cause this problem.

Restricted fuel flow can cause this problem; remove the bolt at the bottom of the carb & check for flow.

On my 1950 frontmount, needing choke to run is the first sign that the points need adjusting/replacing.

Old plug wires can cause the same problem.

A vacuum leak can do the same thing. Get a hand propane torch and carefully spray it (unlit of course) around the intake manifold at the carb to manifold interface & the manifold to block gasket of the tractor while it is running. Or, you can use carb cleaner or WD40. If it speeds up, you found the leak. Sometimes (rarely) manifolds crack or get rust holes.

Lastly, when all else fails, you could have an air leak around the carb metering section. The likely suspects are leaky throttle shaft seals and/or a worn throttle shaft. Or, just a real dirty carb w/ clogged passages.

Bottom line: Probably 75% of "needs choke to run" problems are fuel related, but do not rule out ignition problems. Just check the likely fuel problems first.

Re the break-in, it should be run at variable RPM. Run the engine up to around 1500 RPM and back down, put it in gear and make a few laps around the yard at various speeds.

Please be sure to post back & let us know what the fix was. We all learn something if you tell us what worked!
50 Tips

 

[FMPreacher]

Thanks Bruce, You gave me a lot of good info there. Respectfully though the carb was the only thing that wasn't rebuilt or replaced if it was feaseable. I want the machine to be very dependable. As I was trying to adjust the carb nothing I did to the main jet effected it's running even completely removing it while the engine was running! That's what makes me feel there's thrash in it. Headed to the shop after this post I'll know in a little while.
God Bless You and Your "N"

 

[Bruce (VA)]

You're welcome. IMHO, pull the carb off & rebuild it. Do a search on carb rebuild by GB & JMOR. Great pics & info!
50 Tips

 

[DollarBill]

What's your valued opinon on how to break it in properly?

Reverend, there's two schools of thought on breaking in a new engine. One is baby it for a while and the other is to run the dog wee out of it.

I've done it both ways and can't offer evidence that one method is any better than the other.

Let your conscious be your guide.

 

[FMPreacher]

Well it was exactly as I figured. Something was stuck in the main jet. Got the carb all cleaned up put it back on. Now she runs like she had ought to. Local Tractor dealer advised me to break it in how I intended to use it. I put the bush hog on and did some light to medium mowing at variable RPM's on the lower end though. I'll tell you what though with the difference in power it was worth every penny and minute spent on rebuilding the engine. Man what a difference!!God Bless You & Your "N"

 

[Hobo,NC]

(quoted from post at 01:38:45 10/28/11) Well it was exactly as I figured. Something was stuck in the main jet. Got the carb all cleaned up put it back on. Now she runs like she had ought to. Local Tractor dealer advised me to break it in how I intended to use it. I put the bush hog on and did some light to medium mowing at variable RPM's on the lower end though. I'll tell you what though with the difference in power it was worth every penny and minute spent on rebuilding the engine. Man what a difference!!God Bless You & Your "N"

variable RPM's is the hot tip... Usually 30 min. well above idle and 30 min. just driving it around varying the RPM will do it... After I am sure its up to operating temp,,, all adjustments made,, no leaks and the temp is OK I go for my test run in 4th gear I go from idle to full throttle,,, once it achieves max RPM (2K are so) I slam the throttle back to idle,,, I repeat 10 times... Its like breaking in a automotive engine but you never bring a auto engine to max RPM ....

I really like folks that go the extra mile to help folks BUT it really shows their diagnostic skills are sub par when they chase their tail throwing a monkey wrench into a fuel issue ... Its notcher sparkies and never izz when will they learn.. If it were yer sparkies your main complaint would B get'n the mutta started... Weak spark always shows its tail far'n off a cold engine when max available KV is needed... ... If it lites rite off cold it not weak sparkies and you can take that to the bank...