89 Cat 426B loss of power

[MattCAT89]

Recently came into a 426B Cat backhoe. It ran great with plenty of power but after I repacked several rams, installed new starter it loss nearly all of its power. I replaced the fuel filter and air filter. It runs fine at idle and I can drive it around but it won’t get out of first gear and when you try to use any hydraulics while driving, it boggs down but won’t die just loose its power. Any ideas ??? What would cause it to loose all the torque and power but still run and idle ok ?

 

[heymccall]

Did you change BOTH fuel filters?
Fuel filter, water separator filter, and screen under lid of transfer pump.

 

[MattCAT89]

View attachment 194390 View attachment 194391 View attachment 194392 Did you change BOTH fuel filters?
Fuel filter, water separator filter, and screen under lid of transfer pump.

My parts book doesn’t show a second filter. I have the water separator on one side then on the drivers side the fuel filter.

 

[heymccall]

Well, I suppose I picked the wrong serial number range.

For further discussion, a full serial number would help.

Irregardless, the transfer pump on that Perkins engine will have a screen under a removable top cover. The transfer pump is on the passenger side of engine behind the boom tower upright.

Is it possible that you've displaced a gasket or seal on the fuel separator?

If you did displace a seal on the yellow filter, you'd have a fuel leak. The separator, however, is on the "suck" side of the transfer pump. The yellow filter is on the pressure side.

And, if you loosened any fuel lines at their connections, especially on a machine of that vintage, the rubber compression ring will need replaced.

 

[heymccall]

Does transfer pump look like this? If so, the top comes off.

 

[thepumpguysc]

THATS the set-up that, IF u put the orings ON the filter it chokes off the fuel..
U HAVE TO put the orings UP IN the filter head NOT ON the filter..

 

[oilslick]

Listen to thepumpguy, my dad did exactly what he's talking about and it lost prime. Good luck and report back,eh?

 

[thepumpguysc]

Lol.. Hi Oilslick.. U still runnin strong.??
I remember u.. U guys fought that thing for months & w/ 1 phone call, I screwed myself outta a pump overhaul..Lol