My BX23s has developed a problem where suddenly the rpms will gradually drop and then it backfires and often dies. Sometimes after backfiring it will gradually increase rpms but continue to rev up and down. The tractor is two years old and I had a similar problem without backfire after using the backhoe which turned out to be a switch problem on the seat. I bypassed the seat switches and the problem went away. I changed the air filter and both fuel filters today and then all seemed well as I mowed for about 15 minutes then it started again. Bad thing is when it backfired, the mower deck PTO shaft flew off and slammed the fluid filter causing fluid to spray everywhere. Tomorrow I will clean up the mess and replace hydraulic fluid and filter. Any ideas?
BX23s rpms drop then backfires and dies
- Thread starter Bill Clark
- Start date
85Hokie
Moderator
Staff member
Lifetime Member
Equipment
BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
You have more the one problem going on.....
First the "backfire" - really no such animal in a diesel - but I think I understand what you are describing.
Since you have changed BOTH fuel filters - did you see any contamination in them? Since both are clean now and you bled the system and it runs normal for a while - I would say you have a fuel blockage at the tank nipple. This can be a royal PITA to fix. OR maybe if you are lucky - a restricted fuel cap.
Question - does your fuel pump tick when key is turned to run only?
While you are under the machine - get a large container and see if the fuel hose off the tank will allow fuel to move freely into the container. Should be a steady stream - if it slows - you have found a problem inside the tank!
AS for the PTO coming off - either it was not "snapped" onto the shaft - or it broke, which happened? IF that collar is "clicked" onto the pto shaft - it should never come off in a situation like that.
Did you bypass BOTH seat switches? OR just the one?
First the "backfire" - really no such animal in a diesel - but I think I understand what you are describing.
Since you have changed BOTH fuel filters - did you see any contamination in them? Since both are clean now and you bled the system and it runs normal for a while - I would say you have a fuel blockage at the tank nipple. This can be a royal PITA to fix. OR maybe if you are lucky - a restricted fuel cap.
Question - does your fuel pump tick when key is turned to run only?
While you are under the machine - get a large container and see if the fuel hose off the tank will allow fuel to move freely into the container. Should be a steady stream - if it slows - you have found a problem inside the tank!
AS for the PTO coming off - either it was not "snapped" onto the shaft - or it broke, which happened? IF that collar is "clicked" onto the pto shaft - it should never come off in a situation like that.
Did you bypass BOTH seat switches? OR just the one?
Thanks for the response 85Hokie!
1.) Backfire was the wrong word but it sounded like a backfire on a gas engine. The exhaust blackened the front end loader pivot bar.
2.) Yes, the fuel pump ticks.
3.) Fuel filters were light brown.
4.) Did not dump diesel into a container when I changed the filters to check flow, but when I primed the system with the key switch I watched the front filter fill and it seemed consistent in flow. I will try taking off the hose at the filter and checking flow as you suggest.
5.) Shouldn't have said seat switches. Only bypassed the rear switch which is normally open unless the seat is in the forward- facing position.
6.) When I attached the pto shaft I felt the usual click. Could be it didn't engage all the way. Strange it ran for that long and popped when the engine began lurching. The shaft did not snap but it banged up the yoke pretty good.
Replaced the hydraulic filter, cleaned the screen and replaced the fluid today. What's involved in fixing the problem with a tank blockage? What do you mean by restricted fuel cap? Tank blockage seems to make sense as the run time to failure varies.
Thanks again for the guidance!
1.) Backfire was the wrong word but it sounded like a backfire on a gas engine. The exhaust blackened the front end loader pivot bar.
2.) Yes, the fuel pump ticks.
3.) Fuel filters were light brown.
4.) Did not dump diesel into a container when I changed the filters to check flow, but when I primed the system with the key switch I watched the front filter fill and it seemed consistent in flow. I will try taking off the hose at the filter and checking flow as you suggest.
5.) Shouldn't have said seat switches. Only bypassed the rear switch which is normally open unless the seat is in the forward- facing position.
6.) When I attached the pto shaft I felt the usual click. Could be it didn't engage all the way. Strange it ran for that long and popped when the engine began lurching. The shaft did not snap but it banged up the yoke pretty good.
Replaced the hydraulic filter, cleaned the screen and replaced the fluid today. What's involved in fixing the problem with a tank blockage? What do you mean by restricted fuel cap? Tank blockage seems to make sense as the run time to failure varies.
Thanks again for the guidance!
85 probbly hit the nail on the head,, I know the BX is a royal PIA to change the lower filter,, but I would pull the line right from the tank and check the flow. Also the cap , sometimes critters will mud them up and you will never see it. Take you air gun and blow back into the tank and see if your flow changes. if so you got gunk in your tank. There is no easy way to clean the BX tank, I have heard of guys using a shop vac, with a piece of garden hose on the end to get to the bottom. OH and is the fuel new? You might have some water migrating through the system. And it pays to dump some additives in like the white bottle. I was going to say to check the fuel lines to see if they have gone soft, but 2 years old I doubt... OH wait, a dumb question, you dont think there may have been any cross contamination with gas do you?
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
re: There is no easy way to clean the BX tank,
RIGHT... BTDT.... the ONLY way is to remove tank from the tractor. Found a 'mini plastic bagel', size of an O-ring stuck in the outlet port of the tank.There is NO way (vac, slosh,blow, whatever that would have been able to remove it... I spent 3 leasurely days remove,clean, replace.... local dealer (afterwards) quoted me 3 hrs shop time ( +-$350). If you go the 'removal' PM me. It isn't hard, but seat is HEAVY and awkward and the knob under your butt(PTO posn) is tricky to remove ($8 to replace....),fender pan is 'fun' by toyrself too...
RIGHT... BTDT.... the ONLY way is to remove tank from the tractor. Found a 'mini plastic bagel', size of an O-ring stuck in the outlet port of the tank.There is NO way (vac, slosh,blow, whatever that would have been able to remove it... I spent 3 leasurely days remove,clean, replace.... local dealer (afterwards) quoted me 3 hrs shop time ( +-$350). If you go the 'removal' PM me. It isn't hard, but seat is HEAVY and awkward and the knob under your butt(PTO posn) is tricky to remove ($8 to replace....),fender pan is 'fun' by toyrself too...
85Hokie
Moderator
Staff member
Lifetime Member
Equipment
BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
I swear IF I ever have the problem ..... I think I will go THIS route ..... even though it might not be a perfect answer - but then again for the cost and the time to fix, and IF EVER you needed to get back IN the tank - this would be a perfect answer.
https://fueltankparts.com/collections/custom-flanges-parts-adapters
https://fueltankparts.com/collections/custom-flanges-parts-adapters
the way the tank is shaped, you'd have to put an access panel in the center, and it's not easy to get to. They're not that bad to remove from the tractor if you have to clean it. Looks much worse than it actually is. Remove roll bar, floorboard, rear fender assembly-and the tank is staring you in the face. Plus it gives great access to clean everything.
Thanks to all for the great advice. I haven't had a chance to check the fuel flow out of the tank yet, but will get to it this weekend. The fuel cap restriction is not an issue. The diesel is less than a week old. If the flow looks good I will drain the tank, add new fuel and try the white bottle. If the problem persists, I think I will go lugbolt's route and rip her apart to get to the tank for cleaning. I will get back with y'all on the post-mortem. I truly appreciate all of the help here.
85Hokie - I was still perplexed about the mower PTO shaft coming loose during the misfires. I am sure I felt the firm click when I re-attached the mower deck and it did run for quite a while without issue. After removing the shaft, I saw that the collar spring was broken. Could have happened due to impact after the disconnect (the shaking was pretty violent), or maybe the spring failed during the torquing. No way to ever know for sure.
GreensvilleJay
Well-known member
Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
that 'access port' wouldn't have helped me. You also need a borescope with powerful LED as well as special tools to remove the offending blockage, in my case a black O-ring shape shard of plastic wedged into the fuel exit spigot.
I now have an inlet fuel strainer to prevent 'foreigh bodies' from getting INTO the tank......100+hrs and so far, so good !
I now have an inlet fuel strainer to prevent 'foreigh bodies' from getting INTO the tank......100+hrs and so far, so good !
Attachments
Well, drained the tank at the lower filter inlet and didn't see any flow restriction. Put new diesel in with algicide and fuel treatment, ran it for 10 minutes and then let her sit for two days. Fired it up to mow and went for an hour, then yup, it happened again. When it was acting up I opened the hood and noticed that the front filter was almost empty. I let it sit for a few minutes then turned they key to the first position and couldn't hear the usual pump priming click, nor did the front filter fill with fuel. I'm going to replace the fuel pump this weekend and hope for the best.