743B Fuel injection pump leaking

Help Support SkidSteer Forum:

oracle_of_ferndale

Well-known member
Joined
Feb 12, 2013
Messages
76
There is fuel leaking from the bottom of my injector pump where it bolts to the engine - around the timing shim.

So far I have:

1) changed all of the rubber fuel lines, and checked/tightened all of the steel lines to make sure fuel is not leaking from somewhere else.
2) cleaned both surfaces where the injection pump meets the engine.
3) cussed at the machine and its manufacturers.

None of these stopped the fuel leak.

Do I just need to improve the seal between the injector pump and the engine (maybe a liquid gasket or a new shim?), or is this a symptom of some other problem?

Thanks.
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,839
Is it leaking out of the delivery nozzles or from under the pump?
I have never seen it leaking from underneath, but i have seen it coming from the delivery nozzles where the injector lines connect. There are rubber Orings that seal them between the housing and the delivery nozzles. If you taken them out be VERY careful as this is where your injector is tuned, if things are pulled out, you can mess up the delivery quantities.
 
OP
OP
O

oracle_of_ferndale

Well-known member
Joined
Feb 12, 2013
Messages
76
Is it leaking out of the delivery nozzles or from under the pump?
I have never seen it leaking from underneath, but i have seen it coming from the delivery nozzles where the injector lines connect. There are rubber Orings that seal them between the housing and the delivery nozzles. If you taken them out be VERY careful as this is where your injector is tuned, if things are pulled out, you can mess up the delivery quantities.
It appears to leak from under the pump. I have never removed the delivery nozzles. I will try a bit of sealant and see if it works.
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,839
It appears to leak from under the pump. I have never removed the delivery nozzles. I will try a bit of sealant and see if it works.
No sealant is needed, just new O rings, one on each nozzle, but if it was leaking here, surely you'd see lt around them.
If it's leaking under the shims, i'd be concerned it's getting into the engine too, does the oil smell of diesel at all?
 

jsenicka

Well-known member
Joined
Dec 31, 2017
Messages
45
No sealant is needed, just new O rings, one on each nozzle, but if it was leaking here, surely you'd see lt around them.
If it's leaking under the shims, i'd be concerned it's getting into the engine too, does the oil smell of diesel at all?
If it is one or more of the delivery valves, You need a set of o-rings and copper gaskets Bobcat Gasket Part # 3974368 Bobcat O-Ring Part # 6646730 The other possibility is the seals around the fuel inlet banjo fitting.
 
OP
OP
O

oracle_of_ferndale

Well-known member
Joined
Feb 12, 2013
Messages
76
If it is one or more of the delivery valves, You need a set of o-rings and copper gaskets Bobcat Gasket Part # 3974368 Bobcat O-Ring Part # 6646730 The other possibility is the seals around the fuel inlet banjo fitting.
Thanks. One of the copper gaskets was missing from the banjo.
 
Top