BX1800 Fuel Injector Pump Shims Factory Spec

Does anyone know the standard shim size specifications for the BX1800 fuel injector pump? I could not find a spec in the Workshop Manual. Just want to know how these were set from the factory so I have a good starting point for adjusting the timing.

The previous owner replaced the pump himself, and it has both a 20mm and a 30 mm shim installed.

Thanks

I have not yet performed the spill test. At this point, I was hoping to verify it has a reasonable shim thickness. Based on the symptoms, I am more suspicious of a malfunctioning governor, so I’m going to focus on verifying it’s operation first.

FYI: the engine starts and runs well when not under load. I cannot verify it reaches full rpms since there is no tach, but it winds up pretty fast. However, it struggles under load. Just engaging the 60” mower deckdrops the rpms way down and takes several seconds to wind back up. Mowing on level ground is a struggle in low range. Mowing uphill is almost impossible. I have to inch it forward in order to keep the rpms from dropping too low. I think the symptoms are too extreme to be injection timing alone. I’ve replaced fuel filters and do not think it is a fuel delivery problem at this point. It does not sputter - just does not have much torque. It runs this way consistently. I never get the impression that a governor is engaging to help with the torque. I often have to stop ground motion and let the engine spin back up.

Suggestions are appreciated. Thanks

I should have clarified - it struggles uphill with the mower running and deck raised - not actually doing any mowing work. Agreed a 54 would be best, but I think at a minimum it should be able to move itself around.

I took a look at the governor today - all seems to be in place. The manual identifies an internal governor adjustment screw that affects governor operation under max rpm. I would like to experiment with it. If I am reading the diagram correctly , this is accessed under a cap protruding towards the radiator. The cap is loosely attached but does not come off - at least not easily. Is this the correct location for this adjustment , and how is the cap removed ?

Otherwise, I think the advice to start with the basics of valve lash and timing is my next step. I***8216;ve seen firsthand on another vehicle how a valve adjustment can correct some significant performance issues.

I***8217;m not sure if there is blow-by. Should I check this through the dip/stick?

Thanks

I did the valve lash adjustment and injector pump timing today. The valves all had a bit of extra play, but not way off. I reduced timing shim to one 25mm shim only. The tractor now runs exactly the same - low torque and no sign the governor is trying to compensate for rpms dropping. The engine even feels sluggish imo to rev up without any load. Before I investigate compression , has anyone successfully adjusted the governor or turned up the fuel? How do I get to those adjustments ? Thanks

I removed the fuel tank, cleaned it out, replaced all the fuel line, and repaired the severely leaking fuel sending unit seal with the factory kit. I can now fill my tank without loosing a 1/4 tank of fuel! This was no doubt introducing dirt into the fuel tank. However, it was not clogging up the fuel delivery enough to affect performance.

I decided to remove the cap from the injector pump fuel adjustment and play with this setting. After getting the cap pried off, I first noticed that the adjustment bolt was not secured by the lock nut, and turned freely. Perhaps this was from prying the cap off - who knows. I’m pretty sure the cap had never before been removed. Anyway, after backing the bolt several turns, the engine started to come to life and started to kick out a lot of black smoke when revving the engine. I took it out to the field, and on the way noticed the governor doing its job while going up a hill - sending black smoke out. During the mowing test, it was immediately obvious that it was getting way too much fuel due to the black smoke rolling out. I starting turning the bolt in a turn at a time until only minimal amounts of black smoke appeared under load. This also produced the most torque and effortless mowing since I bought this tractor. Definitely found a sweet spot between too much and too little fuel. I feel this little 18 hp beast is now worthy of being called a tractor. It doesn’t have an over abundance of power, but I feel it is now close to how it should run. It recovers quickly from engaging the mower deck and from high stress situations. I can make it up hills without concern the engine will die.

I think experimenting with the fuel setting could be worthwhile for anyone dealing with a lethargic tractor, but only after verifying the other more common problems are clear. Thanks again!

Thought it may be helpful to someone to provide an update on my bx1800. Despite improving performance by adjusting the fuel, I became increasingly convinced it was still not running as well as it should. ( Remember, I bought it running this way, so I never knew it when running well). The symptoms were poor power and torque (for what I thought an 18 hp tractor should have), poor starting ( could not start it in cold weather, and tons of black smoke), & excess fuel consumption ( from turning up fuel to compensate for the real problem). (I replaced a nonworking glow plug, but didn’t help starting).

My mechanic father-in-law suggested this was a symptom of poor performancing fuel injectors. Said it was probably dumping non vaporized fuel into the cylinders. After unsuccessfully trying concentrated injector cleaner, I ordered new injectors ( non-oem). To make a long story short, this fixed all my problems. The difference was astounding from the first time starting. Purrs like a kitten, loads of power in any situation, no problem running the mower deck and going up steep hills. The little beast is so fun to drive and with only 500 hours should last me a long time. Thanks again.

Yes, I still have the .25mm shim in place. Somewhere along the way I did a second spill test and received the same results, so I think it is correct.