1872 hydrostatic- moving tractor that is not running

[1811Cub]

Does it even sputter a bit if you squirt fuel in the throat of the carb? if not, disconnect the engine to tractor wiring connector to eliminate the key switch and kill circuit. If it runs at that point, then the key switch or kill circuit is at fault. You also must verify compression. An engine needs fuel, spark, timing, and compression to run. On the carbs, the base settings for the mixture screws should be lightly seat them, then back them out 3 turns. Once it is running, then you can fine tune the mixture to best suit your engine.

 

[Gary James]

Good info. Anytime I couldn't get a hit I would try a quick start of starter fluid. Never made a difference. Not compression. Two weeks ago it ran but really rough. After replacing everything and purging the crankcase I got it to run really great, that was until the crappy fuel pump design for the connectors caused leaking.

I'm following the carb setting angle. I've tried everything form almost closed to 5 turns out. One thing, I think I got one hit at the very end of today. The the that has me buffaloed is out of the blue when I got one hit it started after some coaxing. This makes me think about the kill circuit. Isn't the kill circuit the magneto line from the ingition switch? New ignition switch. Maybe a short in the line?

Interesting about the timing. Can you time a magneto? An outstanding question I have had is, even if I see a spark detector light up, can the magneto get weak?

Thanks again, great info.

 

[1811Cub]

Like the previous KT17, the ignition system fires both plugs at the same time. One spark is wasted in one cylinder and the other actually does fire the mixture. If the flywheel to magneto gap is set to .010 then it will be properly set. I'm sure there are minor manufacturing variances in the magnet position that would affect timing, but nothing that can be easily adjusted. I've had to replace a few of these. They are known to go bad. Mine would fail when the engine was warm.

 

[MarcHeld]

Yes, the kill wire runs to the ignition switch. Make sure you have continuity back to the ignition module. (It’s buried behind the cowling on the right rear side.) wires run up through a grommet.

 

[John Kliesrath]

Try some starting fluid or carb cleaner. That will let you know if it’s a fuel problem

 

[Gary James]

That was the first thing I tried. It has never made any difference. I'm going to try this directly into the cylinders.

 

[Gary James]

If it was the kill wire, wouldn't that mean I would never detect a spark?

 

[tkhoffman]

You say you have spark. In spite of that, pull a plug after cranking and look for gas on plug or plug threads. That will verify gas to cylinders and might lean toward bad timing.

 

[Gary James]

I'm leaning toward that assessment. Doesn't that mean pulling the engine? Originally I thought it was a bad coil until it actually fired a few times before the new carb went on. The plugs are moist (unlike when the gas was blowing out of the crankcase and into the cylinders.)

 

[Gary James]

Well, I got it running. It was rough at first but I fiddled with the carb and it is running a lot better. (I'm not a carb guy but I'm getting there.) I don't have a clue except I kept swapping carbs. I got one of the old ones on and it started flooding the crankcase again. I did the same old drain the oil and then I put the new carb back on. It never started when I put it on the first time. I know blowing the cylinders helped getting it started again. Could it have been the temperature that maybe got it to run? Dunno.

Question. I wasn't going to put the Cub Cadet low-ash oil in it so I just went with SAE 30 untill I got this figured out. I plan on eventually going back but does anyone know if there are big differences or concerns for using SAE 30? I have followed a few postings about oil and the 1872. Thanks for the posts!

 

[1811Cub]

Main thing is to stick with the SAE30 weight dino oil. Most oils in that grade are comparable. Make sure the engine is clean, the belly screen is clean, and all insulation from the firewall to the engine is present to ensure proper airflow to keep the engine as cool as possible.

As for the carb, stick with an OEM original Carter/Kohler #26 and rebuild it using a Kohler kit and float. That is the best solution to your problem. I do not like the Walbro fixed jet carbs that commonly came on the M18's. The Chyna carbs are a crap shoot. Some are good..some are really bad.