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Cat 236b isn't getting fuel

J

JFH

Member
Joined
Sep 12, 2016
Messages
5
Location
Poquoson, VA
After replacing the foot throttle on my '05 236B, a new problem arose. The machine starts and runs fine, however when I step on the throttle it runs up, then slowly looses power until it falls back to idle ( even with the pedal pushed down). If I let off the throttle and let the machine run, the machine seems to pump enough fuel to throttle back up, but it again slowly drops off again. I've changed the filter and cleaned the whole assembly thoroughly. I do notice lots of white smoke when I use the throttle, not sure what the next step is.
 
T

thepumpguysc

Senior Member
Joined
Mar 18, 2010
Messages
7,538
Location
Sunny South Carolina
Occupation
Master Inj.Pump rebuilder
I got an "interesting" call this evening.. My Bobcat wont start..
When did this happen.?? I was running it and it quit.. so I changed the fuel filter and now it wont start..
The filter looked completely clogged so I THOUGHT I found my problem.. but it wont start..
Do you have fuel AT THE INJECTORS.?? We loosened one and no fuel..
Do you have fuel TO THE INJ. PUMP.?? No.. We have fuel TO the filter.
But when I take the line off the filter going towards the pump, no fuel..
ME> YA THINK MAYBE the filter head is clogged at the outlet fitting.??!!!!
SEEING YOU GOT FUEL IN AND NUTHIN OUT..
HIM> huh.. I never thought of that.. THANKS.. I'll take it apart and see.... the filter was plugged and coming apart, come to think about it..:eek:
and that's how MY DAY ended..
 
J

JFH

Member
Joined
Sep 12, 2016
Messages
5
Location
Poquoson, VA
Haven't solved the problem yet--236b no fuel

I pulled the suction line, blew ain't through it, then I disconnected all the fuel lines and blew air through them as well. Pulled off the transfer pump, filter, and filter head for a thorough cleaning and replaced. Problem still exists. I plan on draining the fuel tank tomorrow and video scoping the inside of the tank. Hopefully I find something. After that, I'm not sure what else to do. Is the transfer pump bad? I really don't believe it is the injector pump or injectors, but I can't say for sure. It acts as if it is starving for fuel. Suggestions are welcome. I've ne ER had this happen before.
 
D

Delmer

Senior Member
Joined
Jan 3, 2013
Messages
8,891
Location
WI
Completely unscientific observation: white smoke to me means air in the fuel. If it runs out of fuel without air, there's no smoke.

You can check to see where the fuel is to try to narrow down the problem. If it has fuel flow up to the injection pump, you could add a fuel pressure gauge there to see if the problem is upstream or downstream.
 
J

JFH

Member
Joined
Sep 12, 2016
Messages
5
Location
Poquoson, VA
The white smoke only appears as the engine is bogging down, once it has bogged out and returns to idle, the smoke diminishes.
 
D

Delmer

Senior Member
Joined
Jan 3, 2013
Messages
8,891
Location
WI
Yes, the higher fuel demand and a restriction and/or air leak causes the air and white smoke. When idling steady it doesn't demand as much fuel. Of course the white smoke is misfiring, so timing or an internal engine problem will do that also, just where I've seen white smoke. Does this have power to do any work at steady engine speed? or is it just barely enough power to move itself around?
 
J

JFH

Member
Joined
Sep 12, 2016
Messages
5
Location
Poquoson, VA
After pulling the suction hose from the tank and blowing air through it, it ran like a champ until I turned the machine off. Even afterwards, I can get it to run good, but you have to shut it down and start it up a few time. When it does bog down, it runs as it would at idle, so it will power around..at idle strength.
 
B

BlazinSS934

Well-Known Member
Joined
Feb 5, 2012
Messages
125
Location
Long Island, NY
I had a bobcat with a similar problem, rubber suction line would collapse when the engine compartment got warm. So it would start and run for 20-45 min fending on ambient temp and the die.


Sent from my iPhone using Tapatalk
 
J

Jukinju

Member
Joined
Jun 6, 2012
Messages
10
Location
Canada
This was the exact problem I had. Blew out lines, diesel conditioner, several filters, and it seemed to improve temporarily, I was going to replace the fuel pump but $700 made me choose to go deeper.

I found the problem. There was a bunch of junk plugging up the filter housing. I removed the bolt on the left and it was jammed with junk. Blew it out and checked everything else. Was clean.

it’s like I have a new machine
 
charles walton

charles walton

Senior Member
Joined
Nov 24, 2012
Messages
555
Location
Etowah Tennessee
JFH said:
After replacing the foot throttle on my '05 236B, a new problem arose. The machine starts and runs fine, however when I step on the throttle it runs up, then slowly looses power until it falls back to idle ( even with the pedal pushed down). If I let off the throttle and let the machine run, the machine seems to pump enough fuel to throttle back up, but it again slowly drops off again. I've changed the filter and cleaned the whole assembly thoroughly. I do notice lots of white smoke when I use the throttle, not sure what the next step is.
Click to expand...
Did you ever find the problem?
 
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