630 VH4D won't stay running

[Fabricator]

Just went through and changed engine oil and filter and the hydraulic oil, filter, bronze filter, and a hose that was leaking. Working on all of that, I also noticed that the PO had screwed up the fuel shutoff solenoid and taped things back together. So I replaced that as well since I was in there. First time I fired it up things seemed to run well and I went through the motions of driving forwards and back and running the bucket and arms to bleed out any air. Probably ran for ten to twenty minutes. Then it died. Sort of struggled for a bit and was running rough before it just cut off. Since then, I can get it started with some effort and it will run for a minute or two before going into this "struggle" and dying. Seems to be getting fuel and spark, but I haven't torn everything apart. I did pull the solenoid thinking I may have dislodged some crud in the R&R but the filter on the input side is clean. Any suggestions?

 

[BobMelroe]

I'd check the obvious first. Make sure you are getting a good spark, adequate fuel, and everything is connected as it should be. You may have dislodged something, or bumped a wire that has a bad contact. Or maybe something else happened as some sort of weird coincidence. Another poster on this forum has the same problem as you do. Haven't heard from him in awhile, so I'm not sure how he made out.

 

[Fabricator]

I'd check the obvious first. Make sure you are getting a good spark, adequate fuel, and everything is connected as it should be. You may have dislodged something, or bumped a wire that has a bad contact. Or maybe something else happened as some sort of weird coincidence. Another poster on this forum has the same problem as you do. Haven't heard from him in awhile, so I'm not sure how he made out.

Yeah, the fuel shutoff solenoid was one of those "bumped something else" things. The PO had hacked the wires and literally taped them back together with electrical tape. Messing around with the hydraulic hoses pulled the wires apart. When I saw how badly they were butchered I figured I'd just replace the whole unit than mess with it more. I've owned the thing for twelve years and I'm surprised this was the first that problem had surfaced. Definite fuel and definite spark - at least initially. As I said, I can get it to run for a minute or two at a time. So not quite long enough that it would even be "heating up" that causes it to have problems. Relatively new battery and charged up. I don't use the Bobcat frequently, so I'm sure that sitting unused hasn't helped matters. Needing the bronze filter replaced has kept it sitting longer than normal until I could find time to tear it apart. Debating whether to tear apart the carb or the ignition first. I'm sure both could use some attention. The points likely need attention, but I'd expect that to cause a constant issue rather than slowly dying off after a couple minutes.

 

[Fabricator]

Yeah, the fuel shutoff solenoid was one of those "bumped something else" things. The PO had hacked the wires and literally taped them back together with electrical tape. Messing around with the hydraulic hoses pulled the wires apart. When I saw how badly they were butchered I figured I'd just replace the whole unit than mess with it more. I've owned the thing for twelve years and I'm surprised this was the first that problem had surfaced. Definite fuel and definite spark - at least initially. As I said, I can get it to run for a minute or two at a time. So not quite long enough that it would even be "heating up" that causes it to have problems. Relatively new battery and charged up. I don't use the Bobcat frequently, so I'm sure that sitting unused hasn't helped matters. Needing the bronze filter replaced has kept it sitting longer than normal until I could find time to tear it apart. Debating whether to tear apart the carb or the ignition first. I'm sure both could use some attention. The points likely need attention, but I'd expect that to cause a constant issue rather than slowly dying off after a couple minutes.

I did see a couple posts that sounded somewhat similar. This one, but he has a diesel: http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=26817 And there was this one about a 630: http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=25996 I haven't checked compression yet, but I don't think that I have anything that catastrophic. When it is running I can move and raise the arms fully and such. Was there another post that was similar that I haven't found yet?

 

[jerry]

I did see a couple posts that sounded somewhat similar. This one, but he has a diesel: http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=26817 And there was this one about a 630: http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=25996 I haven't checked compression yet, but I don't think that I have anything that catastrophic. When it is running I can move and raise the arms fully and such. Was there another post that was similar that I haven't found yet?

I would suspect the needle valve and float in the carb are sticky and slow to react at times, sitting for a while with gasoline the way it is now will cause this kind of problem.

 

[Fabricator]

I would suspect the needle valve and float in the carb are sticky and slow to react at times, sitting for a while with gasoline the way it is now will cause this kind of problem.

I thought about varnish building up. But I can set the throttle at a constant - it isn't running smoothly because it doesn't run long enough to warm up properly - but at a constant it will just run and then start to die off until it quits. Just odd...

 

[jerry]

I thought about varnish building up. But I can set the throttle at a constant - it isn't running smoothly because it doesn't run long enough to warm up properly - but at a constant it will just run and then start to die off until it quits. Just odd...

Unless it is cold where you are it should not have to warm up to run smooth, just a minute or so and it should be running smooth with no choke on. If you have good flow of gas to the carb I do think the float may be the trouble. sometimes just taking the needle valve out and wiping it with very fine emery or steel wool if it is not neoprene will be all that is needed. First make sure that the flow from the tank doesn't stop or anything when it is allowed to run into a container a few minutes. My 632 had similar trouble this year and it took a new fuel pump to cure it even though the old one had pressure it was low.

 

[jerry]

Unless it is cold where you are it should not have to warm up to run smooth, just a minute or so and it should be running smooth with no choke on. If you have good flow of gas to the carb I do think the float may be the trouble. sometimes just taking the needle valve out and wiping it with very fine emery or steel wool if it is not neoprene will be all that is needed. First make sure that the flow from the tank doesn't stop or anything when it is allowed to run into a container a few minutes. My 632 had similar trouble this year and it took a new fuel pump to cure it even though the old one had pressure it was low.

Does the carb on that engine have the electrical anti diesel solenoid on the bowl? If so they do cause trouble also.

 

[Fabricator]

Does the carb on that engine have the electrical anti diesel solenoid on the bowl? If so they do cause trouble also.

Many thanks for the advice from everyone. No electric running to the carb, so I'm guessing it doesn't have the anti-diesel solenoid. Looks like I'll pull the carb apart and clean that up. But first I'll see what the fuel delivery is for a couple minutes just to make sure of that. I verified that I was getting fuel, but not for more than a couple seconds.

 

[OldMachinist]

Many thanks for the advice from everyone. No electric running to the carb, so I'm guessing it doesn't have the anti-diesel solenoid. Looks like I'll pull the carb apart and clean that up. But first I'll see what the fuel delivery is for a couple minutes just to make sure of that. I verified that I was getting fuel, but not for more than a couple seconds.

Have you tried running it with the fuel cap off just in case the vent is clogged.

 

[Fabricator]

Have you tried running it with the fuel cap off just in case the vent is clogged.

Sometimes it is the simplest things, isn't it? I'll add that to the top of my checklist.

 

[Fabricator]

Sometimes it is the simplest things, isn't it? I'll add that to the top of my checklist.

Ok, I'm not sure if I'm making progress or not. I took the grill off the top of the engine compartment to get up close and personal with things. Realized I should have done that to replace the fuel shutoff solenoid instead of reaching in through the back at arms length... Took the needle valve out and cleaned it off as suggested by Jerry. There was some buildup, but it didn't look that bad. While I was there, I adjusted the governor and choke according to the directions in the manual. Then cracked the fuel cap a bit just to make sure it wasn't vacuum locked as Old Machinist suggested. As I side note, it has about 3/4 tank of fresh fuel. A few cranks and some adjustment of the idle screw and I got it running. Let it just go at a fast idle for about five minutes and it seemed to be doing ok. So I went through the motions with the arms and bucket and driving it back and forth a bit. No troubles. Seemed to run pretty strongly. So back and forth in the lane a bit and still no troubles. Actually, with the governor and choke adjustments it was running stronger than it has in the recent past. So I've had a load of brownstone wall stones in the pickup since the Bobcat was blocking access to where I wanted to store them. Drove the Bobcat up to the back of the pickup, leveled the bucket to the tailgate, and idled it down while I jumped in the pickup bed and loaded the bucket up with stones. Drove them down to where I wanted to stock pile them, idled down again, got out, and unloaded and stacked the stones. Back up the pickup for a second bucket full. Unloaded. Back up to the pickup for a third bucket full. Down to unload. As I was reaching the unloading pile with the third load and was turning to line up with it, suddenly it started struggling and died out pretty much like it did before. Tried to get it started, but it would only catch for a moment, struggle, and die out. Same as before. Had some rain showers coming in and I have to get over to my folks for the evening, so I didn't have time to mess with it any more today. I did check to make sure that the fuel cap didn't vibrate closed to create a vacuum, but other than that there didn't seem to be any difference from when it was running. All told, I'd say I had it running about forty minutes today. At this point, my thoughts are: 1) crud in the fuel that is sporadically getting sucked in and causing problems? 2) intermittent problem with the float? 3) intermittent problem with the fuel pump? Have to dig in to this some more tomorrow. I was all ready to dance a jig today when it was running because I thought I had it licked.

 

[Tazza]

Ok, I'm not sure if I'm making progress or not. I took the grill off the top of the engine compartment to get up close and personal with things. Realized I should have done that to replace the fuel shutoff solenoid instead of reaching in through the back at arms length... Took the needle valve out and cleaned it off as suggested by Jerry. There was some buildup, but it didn't look that bad. While I was there, I adjusted the governor and choke according to the directions in the manual. Then cracked the fuel cap a bit just to make sure it wasn't vacuum locked as Old Machinist suggested. As I side note, it has about 3/4 tank of fresh fuel. A few cranks and some adjustment of the idle screw and I got it running. Let it just go at a fast idle for about five minutes and it seemed to be doing ok. So I went through the motions with the arms and bucket and driving it back and forth a bit. No troubles. Seemed to run pretty strongly. So back and forth in the lane a bit and still no troubles. Actually, with the governor and choke adjustments it was running stronger than it has in the recent past. So I've had a load of brownstone wall stones in the pickup since the Bobcat was blocking access to where I wanted to store them. Drove the Bobcat up to the back of the pickup, leveled the bucket to the tailgate, and idled it down while I jumped in the pickup bed and loaded the bucket up with stones. Drove them down to where I wanted to stock pile them, idled down again, got out, and unloaded and stacked the stones. Back up the pickup for a second bucket full. Unloaded. Back up to the pickup for a third bucket full. Down to unload. As I was reaching the unloading pile with the third load and was turning to line up with it, suddenly it started struggling and died out pretty much like it did before. Tried to get it started, but it would only catch for a moment, struggle, and die out. Same as before. Had some rain showers coming in and I have to get over to my folks for the evening, so I didn't have time to mess with it any more today. I did check to make sure that the fuel cap didn't vibrate closed to create a vacuum, but other than that there didn't seem to be any difference from when it was running. All told, I'd say I had it running about forty minutes today. At this point, my thoughts are: 1) crud in the fuel that is sporadically getting sucked in and causing problems? 2) intermittent problem with the float? 3) intermittent problem with the fuel pump? Have to dig in to this some more tomorrow. I was all ready to dance a jig today when it was running because I thought I had it licked.

If it was mine, i would pull the carb off and pull it down, clean everything with carby cleaner. Blow out all the jets, clean every little thing, you then know your carby should be in great shape. It could be a piece of rubish floating around causing all these dramas. When the carby is clean, install a NEW inline fuel filter between the tank and carb, then you know if there is any junk on the tank its not getting in your nice clean carb.
That is where i would start. It may be a little work, but you will at least eliminate one thing.

 

[Fabricator]

If it was mine, i would pull the carb off and pull it down, clean everything with carby cleaner. Blow out all the jets, clean every little thing, you then know your carby should be in great shape. It could be a piece of rubish floating around causing all these dramas. When the carby is clean, install a NEW inline fuel filter between the tank and carb, then you know if there is any junk on the tank its not getting in your nice clean carb.
That is where i would start. It may be a little work, but you will at least eliminate one thing.

Yep, eliminate things step by step.

I think that the idea of something floating around the carb and mucking things up is more likely than muck from the fuel tank causing problems. I do have a fairly new filter downstream of the tank. One of the first things I did was pull that out and make sure that fuel was flowing through it. I've also checked the screen on the inlet of the fuel shutoff solenoid three times now with nothing showing up.

Futzing around with the needle valve may have displaced the bugger and let it run - only to die when the bugger came back around and blocked something up again.

If nothing else, a clean carb isn't going to hurt matters at all.

 

[Fabricator]

Yep, eliminate things step by step.

I think that the idea of something floating around the carb and mucking things up is more likely than muck from the fuel tank causing problems. I do have a fairly new filter downstream of the tank. One of the first things I did was pull that out and make sure that fuel was flowing through it. I've also checked the screen on the inlet of the fuel shutoff solenoid three times now with nothing showing up.

Futzing around with the needle valve may have displaced the bugger and let it run - only to die when the bugger came back around and blocked something up again.

If nothing else, a clean carb isn't going to hurt matters at all.

P.S. Just figured that I didn't have HTML turned on so my posts were getting all quashed together. Sorry about that.

 

[Fabricator]

P.S. Just figured that I didn't have HTML turned on so my posts were getting all quashed together. Sorry about that.

Picked up a carb rebuild kit this week from the dealer for under $40. Took the carb off and have been soaking it since Thursday. What a grimey mess! Inside looked pretty decent, though.

Hopefully I can get it back together today and this will clear up the problems.

 

[Fabricator]

Picked up a carb rebuild kit this week from the dealer for under $40. Took the carb off and have been soaking it since Thursday. What a grimey mess! Inside looked pretty decent, though.

Hopefully I can get it back together today and this will clear up the problems.

Ok, got the carburetor all cleaned up, everything disassembled, new parts installed, and everything back together. Still nothing...

It's getting spark - pulled two spark plugs and tested. It's getting fuel - pulled the hose where it goes into the bowl of the carb. But hard to say whether it is getting good spark and whether it is getting a steady supply of fuel. But it is getting enough fuel that it should at least catch.

This is going to drive me nuts at this rate!

 

[Fabricator]

Ok, got the carburetor all cleaned up, everything disassembled, new parts installed, and everything back together. Still nothing...

It's getting spark - pulled two spark plugs and tested. It's getting fuel - pulled the hose where it goes into the bowl of the carb. But hard to say whether it is getting good spark and whether it is getting a steady supply of fuel. But it is getting enough fuel that it should at least catch.

This is going to drive me nuts at this rate!

With the age and the little that I've had to put into it in the past twelve years I've owned it, I really can't complain about putting new parts into it.

When I bought it, I put in a new starter solenoid, new plugs and wires, new distributor cap and rotor, replaced a couple hydraulic lines, fixed an axle seal, and made some adjustments. She's served me well ever since. As this is a machine for personal stuff around my property for the most part, I've probably put less than a thousand hours on her in the last twelve years.

But I would like to get it running again and the order parts, wait for them, put them in, doesn't work, order more parts, wait for them, etc, etc, has been going on for awhile now.

I'm thinking that a fuel pump, new spark plugs, and new spark plug wires are likely warranted in any case. But I'm wondering if there is anything else I should add to the list? I've considered one of the Pertronix setups to eliminate the points - something I hate tinkering with. If I do that, I'll likely replace the coil as well - as I said in the last post, I'm not sure how good of a spark I'm getting.

But the crazy thing is that I had it running pretty good for awhile there and then nothing. It seems that as well as it was running I should at least be able to get it to catch or run rough or something.

 

[Fabricator]

With the age and the little that I've had to put into it in the past twelve years I've owned it, I really can't complain about putting new parts into it.

When I bought it, I put in a new starter solenoid, new plugs and wires, new distributor cap and rotor, replaced a couple hydraulic lines, fixed an axle seal, and made some adjustments. She's served me well ever since. As this is a machine for personal stuff around my property for the most part, I've probably put less than a thousand hours on her in the last twelve years.

But I would like to get it running again and the order parts, wait for them, put them in, doesn't work, order more parts, wait for them, etc, etc, has been going on for awhile now.

I'm thinking that a fuel pump, new spark plugs, and new spark plug wires are likely warranted in any case. But I'm wondering if there is anything else I should add to the list? I've considered one of the Pertronix setups to eliminate the points - something I hate tinkering with. If I do that, I'll likely replace the coil as well - as I said in the last post, I'm not sure how good of a spark I'm getting.

But the crazy thing is that I had it running pretty good for awhile there and then nothing. It seems that as well as it was running I should at least be able to get it to catch or run rough or something.

Ok, rather than pull everything back apart again, I was able to reach under the carb and remove the access plug for the main jet. No fuel came out. The plug sits at the bottom of the bowl, so I was expecting at least something...

So it looks like ordering a new fuel pump Monday morning is the next step in this story.