F12 problems...

Hey guys,

I've posted a couple of times about my F12, maybe you remember the pictures and video.

I replaced the carburetor with a brass one that I cleaned up and rebuilt. The issue now is that I can't hand crank it. I pull started it, and after about 10-12 impulses it started and runs great!

I took the carb back off of the tractor and checked the gaskets to make sure that I didn't have an air leak, everything is sealed up tight now.

I have double checked the timing and everything looks good there as well.

I'm running it off of a jumper tank right now (not through the fuel pump), but it is getting plenty of gas.

The Mag is super hot, I can jump almost a full 1/2 inch with the spark.

I'm sure there could be several things to check, I'm just wanting to get this thing hand cranking again before I tear it all the way down to start painting.

Thanks in advance guys!

Richard

I at one time had the same problem. It didn"t want to start, but when it did, it would run rough and you could really hear the impulse working until after about 12-15 impulses. When you are timing your mag, make sure the pointer (#2) on your rotor is pointing in the exact direction. I"m assuming you are lining up the #1 piston on TDC of the flywheel. Another thing I found is the pawl of the impulse coupling can be worn and/or dry. If you have the mag off of the tractor, you can lubricate the pawl/impulse assembly. If it is still on the tractor, put a few drops of oil in the lubricating port on top of the impulse cover. Hope this helps, at least its someplace to start.

Try a squirt of starting fluid in the intake before you crank it. I
have two f 12"s one starts right up but the other is hard to start
unless I use a little starting fluid. I don"t know why this is. I
have gone through the carb and mag and everything seems to
be set right. Did a compression check and all cylinders are
between 60 and 65 lbs. don"t know if this is low or not. Let us
know if this helps you.

You told us last time that this tractor crank started with the original carb, you then changed the carb to a brass one and now it won't start with the crank. That tells me something is not quite right in your brass carb. F12s can be very touchy starters, you need to check and double check everything in that carb from float level to every nook and cranny in every passage. You may need to adjust the jets a little at a time until you hit the sweet spot. Play with the throttle position..etc etc... until you find it.

As for using starting fluid in a hand crank tractor. That may just be the worst piece of advice ever given on here. These tractors can and have hurt/killed people during a kickback. This is why everyone advises you to use only upstrokes and tuck your thumb. Just a touch of either would compound the kickback drastically. If you want to use it go ahead, its your arm, but I would never ever recommend using it to anyone else unless using a belt or pull starting the tractor.

36F30,

Yes, I had it hand cranking... usually on 3-4 cranks with the other carb. I've put it back on, but it still won't hand crank. I went back through the brass one, and it's super clean. It runs great, but only starts when being pulled.

I've been out of town this week, but I plan to work on it more on Friday.

(quoted from post at 14:15:51 09/18/13) 36F30,

Yes, I had it hand cranking... usually on 3-4 cranks with the other carb. I've put it back on, but it still won't hand crank. I went back through the brass one, and it's super clean. It runs great, but only starts when being pulled.

I've been out of town this week, but I plan to work on it more on Friday.

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It concerns me that you are using a temporary tank. I know guys that fight their fuel pumps, some have welded up the ends of the push rod to make up for wear and get a full stroke on the pump again. If it were mine I would get everything hooked back up properly and go step by step through the system. Get the whole thing working as one system. Once everything is in place and working , fuel-spark-and compression then you can start tweaking things to get it right. Once you get it dialed in and figure out the exact way your tractor likes to start you will be happy with it. My 30 has 8,000ft pistons in it, not fun to crank but I have figured out it needs to be set at 2/3 throttle,open the fuel valve,(Fairbanks mag, can't change the advance setting), then pull the choke fully and crank it over 1 full revolution -gas will then drip out the vent, open the choke back up and then it usually fires on the second pull. I have several other hand start tractors and each one has a different routine to start it. I have watched my brother in law crank on our old JD GP for twenty minutes without so much as a puff, I can then walk over and start it in 2 -3 rolls of the flywheel. Also got a B that everybody else has given up on and pulls it, I start it by hand. Bottom line is You are going to have to figure out your procedure for your tractor.