BX 22 High RPM misfire

dodge man · May 13, 2013

Just another thought, a lot of people have had problems with debris in their fuel tanks. Something like a leaf will move away from the intake of the tank, but after it runs a while will get sucked into the intake and plug it off part way. I could never figure out how this could happen, but I was fueling my Bx yesterday and it was very windy, it has a large opening to the tank, so I can see how stuff could end up in the tank.

Adjusting the valves is something you can do yourself if you have the ability and the tools. I've never done it myself, but from what I've read about it, its something I would try my self. I can't remember the service interval, but I bet its due for your tractor if its never been done. My vague understanding of the process is you pull the valve cover and adjust the lifters using a feeler gauge.

ehenry · May 13, 2013

I haven't seen anyone mention this.......When you removed the filter under the tractor, did you see any water in it? Water will make one run like crap.

I've got a BX22 1300+ hours that has the exact same problem. I'm wondering if the electric fuel pump is starting to fail when the tractor come up to temprature. The tractor will run with out the electric pump but it will missfire and not have any power.

I've got two new filters and plan on draining the fuel tank and refilling with fresh fuel from a well used truck stop. I'm also going to replace all the factory hose clamps with clamps that you have to screw to tighten to eleminate the sucking of air when the tractor warms up. If this doesnt fix it then I'll check the valve clearances.

anyone know if you set the valves on this engine with it hot or cold?

Also, if you find the issue with your tractor PLEASE post it or PM me.

DOC4444 · May 13, 2013

Replacing the filter did not work, as previously noted. I just found this: http://www.tractorbynet.com/forums/...learance-adjustment-d905-valve-adjustment.jpg

Anything I should know about glow plug removal?

I assume I will need to replace the valve cover gasket. Are there crush washers, seals, etc. needed to reinstall glow plugs?

Thanks!

DOC

oldnslo · May 14, 2013

ehenry said:
If this doesnt fix it then I'll check the valve clearances.

anyone know if you set the valves on this engine with it hot or cold?

Valves are checked with the engine cold.

DOC4444 · May 14, 2013

RATS! Did not work. It made so much sense and I found one rocker with only half a thou clearance. However, the pattern did not change. It ran perfectly from cold up to the point it reached FOT, then started misfiring, as before. Hard to imagine valve got burned and how could it run so well all the way up to FOT.

The motor was overheated 500 hours ago, but other than needing a water pump, it has been pretty good. What else could be happening when it gets fully warm? Coolant is getting into combustion chamber? Too much fuel to combust when hot?

Am having it picked up by the dealer tomorrow, unless someone convinces me otherwise.

BTW, it was pretty easy to turn the motor with a big lever on the flywheel without GPs removed, MUCH easier than I would have expected. Is this a sign of poor compression? It runs so well from cold that I have a hard time imagining compression is low.

Thanks again,

DOC

ehenry · May 15, 2013

I plan on running my tractor this afternoon moving some dirt. This will be after draining the tank a 2nd time, 2 new filters and fresh store bought fuel. I plan on having the tools with me to immediately pull the hose from the output side of the secondary filter to check flow from the electric fuel pump to see if its failing when it gets hot.

I'll post what I find.

ehenry · May 18, 2013

I got to run my BX yesterday for about an hour after draining the tank completely and refilling with fresh fuel and replacing both filters. When the tractor started missing and spitting I shut it down and pulled the top hose off the 2nd filter, turned the key back on and fuel just dribbled. It appears that the electric pump is failing after it gets hot.

Got a new pump ordered.

DOC4444 · May 18, 2013

How long after starting from cold did the misfire start? Did you check fuel flow coming out the front filter when cold, BEFORE it started misfiring so you had something to compare it to when you checked it hot?

Thanks!

DOC

ehenry · May 18, 2013

I ran the tractor probably 30 to 40 minutes full throttle. Prior to starting ,I checked flow from the out side of the 2nd filter just before the mechanical pump and had good flow. Now, it didnt squirt out and hit the ceiling or anything like that but it was a good steady flow. When the tractor started missing I shut it down, pulled the hose from the out side of the 2nd filter and didnt have the flow I had prior to startup. Also, the pump didnt sound as it normally does. I checked the out side flow of the first filter between the tank and the electric pump as well and had good flow there. I feel confident that the electric fuel pump is my problem. If not..... I got a spare pump !

I also still have a pile of dirt to move and will jump back on it when I get the new pump installed and post if the problem is fixed.;