Help me help a good friend - Bobcat 873 starting/running issues

[Tazza]

fixed typo

I guess it could be a leaky one way valve. Can you get hold of a hand primer? or does it have one fitted? Can you try squeezing it and getting someone to crank the engine while you do this? it will essentially give you more fuel pressure to the pump. If it starts up, it would confirm its a fuel suply problem.

 

[DigitalFusion]

I guess it could be a leaky one way valve. Can you get hold of a hand primer? or does it have one fitted? Can you try squeezing it and getting someone to crank the engine while you do this? it will essentially give you more fuel pressure to the pump. If it starts up, it would confirm its a fuel suply problem.

it doesnt have a primer ball. Where is the one-way valve, in the pickup in the tank?

 

[Tazza]

it doesnt have a primer ball. Where is the one-way valve, in the pickup in the tank?

Usually in the tank, but the lift pump i thought would have one as well. If you can fit a primer bulb to it just see, it wouldn't hurt. The type i'm talking about are like what you have on a boat. Give it a squeeze and hold it then try and start.

 

[DigitalFusion]

Usually in the tank, but the lift pump i thought would have one as well. If you can fit a primer bulb to it just see, it wouldn't hurt. The type i'm talking about are like what you have on a boat. Give it a squeeze and hold it then try and start.

and where would a guy put one of those in?

 

[thetool]

and where would a guy put one of those in?

From the looks of your picture it looks like someone remove the primer ball and put in an in-line fuel filter? As said, you need the squeeze ball with its check valve to keep from loosing your prime. The ball goes where that in-line filter is.
Also, at your lift pump, if you remove the screw in the middle of the plastic cap there is a screen in there that gets clogged up sometimes-easy to check.
That is most definitley a Deutz engine.
I still thing you need to check compression, and now reading, especially seeing how much ether has been used.

 

[DigitalFusion]

From the looks of your picture it looks like someone remove the primer ball and put in an in-line fuel filter? As said, you need the squeeze ball with its check valve to keep from loosing your prime. The ball goes where that in-line filter is.
Also, at your lift pump, if you remove the screw in the middle of the plastic cap there is a screen in there that gets clogged up sometimes-easy to check.
That is most definitley a Deutz engine.
I still thing you need to check compression, and now reading, especially seeing how much ether has been used.

he said he purchased the 'cat with this issue, and with the inline filter there. Is there some special primer ball we need to buy? Do all primer balls have a check valve in them?
I assume you are talking about the screw/cap that is directly above and to the left of the dipstick in the picture above?

 

[DigitalFusion]

he said he purchased the 'cat with this issue, and with the inline filter there. Is there some special primer ball we need to buy? Do all primer balls have a check valve in them?
I assume you are talking about the screw/cap that is directly above and to the left of the dipstick in the picture above?

I picked up a primer ball with a check valve. We couldnt get the machine started right away. After a tiny shot of ether it started. We shut it down and went back to it about 35-40 mins later, and it fired right up... something it will not normally do. I then let it sit for another hour, maybe an hour and a half and tried to start it... it just wouldnt go.
Is there supposed to be another check valve on the return line after the injectors? There is a splice in the line there that looks like something is suppose to be there... right up by the air filter?

 

[Tazza]

I picked up a primer ball with a check valve. We couldnt get the machine started right away. After a tiny shot of ether it started. We shut it down and went back to it about 35-40 mins later, and it fired right up... something it will not normally do. I then let it sit for another hour, maybe an hour and a half and tried to start it... it just wouldnt go.
Is there supposed to be another check valve on the return line after the injectors? There is a splice in the line there that looks like something is suppose to be there... right up by the air filter?

Only one check valve is needed, the other line is simply the tap off lines, these just flow back to the reserve tank, no pressure here.
I have to agree with thetool, compression test is next. Starting juice does have lubricants in them, but they really are to be used as a last resort.

 

[thetool]

Only one check valve is needed, the other line is simply the tap off lines, these just flow back to the reserve tank, no pressure here.
I have to agree with thetool, compression test is next. Starting juice does have lubricants in them, but they really are to be used as a last resort.

He needs a con o' Start, ye barstard! LOL

 

[Tazza]

He needs a con o' Start, ye barstard! LOL

hehehe so true! I need to take a picture of it next time i'm in the store!!!

 

[DigitalFusion]

hehehe so true! I need to take a picture of it next time i'm in the store!!!

either of you two know what size fitting it is for the compression test? How do I shut off the fuel to do the compression test?

 

[DigitalFusion]

either of you two know what size fitting it is for the compression test? How do I shut off the fuel to do the compression test?

oh, I dont think I mentioned it, but I pulled the screen on the pump, it was spotless.
List of items done thus far:

• Checked fuel pickup - ok as far as we can tell
• Replaced all fuel feed lines (except the one between the primerball and pickup)
• Replaced fuel return line between injectors and splice by air filter
• Replaced primer ball
• Replaced fuel pump
• Replaced hard steel fuel lines on injector.
• Replaced glow pugs
• Checked screen on fuel pump
• Bleed fuel lines

So now it looks like its got low compression is what you guys think? My friend is gonna be bummed if thats the case. Is there still a possibility that its injectors or the injector lift pumps leaking? We have a buddy who is a diesel machanic (heavy trucks). He said he can take the injectors into work and test/clean them. He looked at the machine and was the one who bleed the fuel lines. He really didnt think there would be any reason why it would be an injector issue, and really thought it was one of the lift pumps leaking. He couldnt tell since I just moved to this house and dont have my air compressor hooked up to blow off the pump and watch to see if it was leaking.

 

[DigitalFusion]

oh, I dont think I mentioned it, but I pulled the screen on the pump, it was spotless.
List of items done thus far:

Checked fuel pickup - ok as far as we can tell
Replaced all fuel feed lines (except the one between the primerball and pickup)
Replaced fuel return line between injectors and splice by air filter
Replaced primer ball
Replaced fuel pump
Replaced hard steel fuel lines on injector.
Replaced glow pugs
Checked screen on fuel pump
Bleed fuel lines

So now it looks like its got low compression is what you guys think? My friend is gonna be bummed if thats the case. Is there still a possibility that its injectors or the injector lift pumps leaking? We have a buddy who is a diesel machanic (heavy trucks). He said he can take the injectors into work and test/clean them. He looked at the machine and was the one who bleed the fuel lines. He really didnt think there would be any reason why it would be an injector issue, and really thought it was one of the lift pumps leaking. He couldnt tell since I just moved to this house and dont have my air compressor hooked up to blow off the pump and watch to see if it was leaking.

sorry, I have been using the wrong terminology... when I say lift pumps, I mean the injector pumps.

 

[skidsteer.ca]

we just checked the pickup, its fine, the screen is clear, and we can hear the check valve bb rattle if we shake it. What are these things? They seem to be leaking, seems like a good bet they are the cause?

I too think you have a leak in the fuel sytem lines someplace that is letting air get inside and when the machine goes to start it does not have any fuel so it won't fire up.
Deutz appears (note I'm not a deutz mechanic or owner) to use a camshaft operated injection systen instead of a normal injection pump. These are common on the old detroit diesel 2 strokes In the cam system a lobe on the camshaft come around and forces the fuel spray out the injector at the correct time. At any rate did you get the leaks cured that are seen in the photo of the engine?
If you take a can of fuel and elavated it above the engine by placing it on something, and connect the fuel pick and return lines to it. Be sure to submerge the end of both lines under the fuel. Get the engine running on this can of fuel for ten minutes or so. This should ensure any that air that was in the fuel system was purged out the fuel return line to the can.
Watch the return fuel line to see if any air bubbles are coming out of it. If there is, see if they go away after a longer run time. If they are still there, some component on the fuel system is defective and in letting air from either the outside or from within the crankcase of the motor into the fuel system.
Now shut it down, with the fuel supply elevated it is now trying to gravity feed to the engine. Look all over to see if you have any leaks. Leave it sit for several hours or a day or so and see if it will start. This will eliminate the possibillity of the fuel leaking back. If the compression is low the engine should still smoke when you try to start it cold. If you have no smoke when you crank it over the fuel is not being delivered to the engine for what ever reason.
Ken

 

[siduramaxde]

I too think you have a leak in the fuel sytem lines someplace that is letting air get inside and when the machine goes to start it does not have any fuel so it won't fire up.
Deutz appears (note I'm not a deutz mechanic or owner) to use a camshaft operated injection systen instead of a normal injection pump. These are common on the old detroit diesel 2 strokes In the cam system a lobe on the camshaft come around and forces the fuel spray out the injector at the correct time. At any rate did you get the leaks cured that are seen in the photo of the engine?
If you take a can of fuel and elavated it above the engine by placing it on something, and connect the fuel pick and return lines to it. Be sure to submerge the end of both lines under the fuel. Get the engine running on this can of fuel for ten minutes or so. This should ensure any that air that was in the fuel system was purged out the fuel return line to the can.
Watch the return fuel line to see if any air bubbles are coming out of it. If there is, see if they go away after a longer run time. If they are still there, some component on the fuel system is defective and in letting air from either the outside or from within the crankcase of the motor into the fuel system.
Now shut it down, with the fuel supply elevated it is now trying to gravity feed to the engine. Look all over to see if you have any leaks. Leave it sit for several hours or a day or so and see if it will start. This will eliminate the possibillity of the fuel leaking back. If the compression is low the engine should still smoke when you try to start it cold. If you have no smoke when you crank it over the fuel is not being delivered to the engine for what ever reason.
Ken

This is just a thought and I've never had the engine apart but what about the fuel shut off solenoid? Maybe it's not allowing to fuel rail to open fully? Or maybe the solenoid is going bad and not opening all the time????

 

[Tazza]

This is just a thought and I've never had the engine apart but what about the fuel shut off solenoid? Maybe it's not allowing to fuel rail to open fully? Or maybe the solenoid is going bad and not opening all the time????

It is possible.... I just don't know how its setup in that machine....