Lack of Power Fuel Issues 763

[nobull1]

For the last couple of months I have found that the Bobcat seemed to be dieing out (almost stalling) under heavy load and sometimes hard to start when left for any amount of time. The last couple of days for no reason the machine would just die and I had to squeeze the primer and prime the system After doing this, sometimes it would work for an hour or two with out issues. I decided to take a look at the pickup tube in the tank to see if that could be the problem. Lucky for me the grommet came right out and I was left holding the elbow and about a 1/2” of the pickup tube attached just above the bottom of the elbow. I suspect that the tube completely broke off while I was trying to remove the grommet because it would run with a 1/2 tank of fuel before I removed the grommet. I believe that the line was cracked or partially broke and allowing air to enter along with the fuel. Sometimes it would get more air when under load and enough to starve the system for fuel.
So I tried to get a new line, filter and check valve and was told by Bobcat it would be a couple of days. So I went to my shop and found a piece of 1/4” black rubber gas line hose that was a tight fit onto the elbow. So I just cut it to the length Bobcat said it was at 9.5” and installed it. I used the machine for about a hour and worked fine and seemed to have more power under load as well. For the cost of the parts I ordered them from Bobcat anyways.
The questions are

1. Is the black gas-line hose acceptable or maybe even better than the Bobcat hose?
2. Do you need the clamps that hold the line to the elbow (must be small as there is no room for much more than the hose)?
3. The old hose is in the tank so do I need the filter check valve or will it possibly cause more grief than it will repair (plugging up and having to remove the pickup to clean)? Or will letting the potential junk come through be a bigger problem?

Brian

 

[waggles]

If the fuel hose is not affected by the fuel fine ! My old 743 had a plastic hose with no clamps at all that slipped thru the rubber grommet , it fell off inside the tank along with filter on the end. I left it there and just replaced them both with new hose and filter. No problems. You could remove the tank and empty it out but thats a big job on 763.

 

[OldMachinist]

If the fuel hose is not affected by the fuel fine ! My old 743 had a plastic hose with no clamps at all that slipped thru the rubber grommet , it fell off inside the tank along with filter on the end. I left it there and just replaced them both with new hose and filter. No problems. You could remove the tank and empty it out but thats a big job on 763.

If the line you used is rated for diesel then it shouldn't be a problem. When my pickup tube broke off in the tank I found that the spring clamp at the screen/check valve was magnetic and was able to fish it out with a strong magnet attached to a piece of steel rod. I would try to get the old tubing out because it may break up into small pieces and clog the elbow.

 

[skidsteer.ca]

If the line you used is rated for diesel then it shouldn't be a problem. When my pickup tube broke off in the tank I found that the spring clamp at the screen/check valve was magnetic and was able to fish it out with a strong magnet attached to a piece of steel rod. I would try to get the old tubing out because it may break up into small pieces and clog the elbow.

Brian
I wonder if the lift pump on the motor is failing. Sometimes it pumps and others it does not.
Try extending the fuel line temporarily so you can have the squeeze bulb primer in the cab.
When its seem down on power see if pumping the bulb helps restore normal power.
If you think it is related to the suction line or tank a temp fuel tank aka 1 gallon oil jug full of fuel to supply the engine will let you test if a new tanks makes all things well again.
Ken

 

[nobull1]

Brian
I wonder if the lift pump on the motor is failing. Sometimes it pumps and others it does not.
Try extending the fuel line temporarily so you can have the squeeze bulb primer in the cab.
When its seem down on power see if pumping the bulb helps restore normal power.
If you think it is related to the suction line or tank a temp fuel tank aka 1 gallon oil jug full of fuel to supply the engine will let you test if a new tanks makes all things well again.
Ken

Old Machinist
When the new line and other parts come in this week I will just have to make a judgement call of what to use. You made a point by saying is it rated for diesel? Good question as I know it is rated for gas and I just never thought about diesel, probably is but I will investigate further. I will try to use a magnet as you suggested, regardless. If I can fish it out good if not well, I tried.
Ken
Time fly's when your having fun, yeah right, about a year since we talked.
You might know since I returned a few weeks ago, I now have issues. All was well for the last year or so, now pow.
Anyhow I was thinking possibly lift pump as well until I removed the grommet at the tank and found no hose on the end of the ninety. I was somewhat careful removing the grommet and no way would I have broken an intact hose off. The remaining hose on the ninety was semi soft, not brittle and must have been at least partially broke IMO and sucking air. I believe the hose must have been there or it would not have worked with half a tank of fuel just before I took it apart. The other reason I was thinking it wasn't the pump was after it stalled the primer bulb was not collapsed and when I squeezed it for the first few pumps there was no fuel in it. I didn't think that a bad pump would allow air to be in the primer bulb? I could be wrong though and await your answer. The other thing is I do not know the mechanics of those lift pumps and wonder if they could be intermittent or if they would slowly pump less. Maybe you know and can educate me. The other reason I now think it isn't the pump is since replacing the line the machine has worked fine (at least yesterday) and “appeared” to have more power when under load. All I can do is keep trying it and see if the problem arises again. Last two times it happened I was almost trapped in the machine with the door on and the loader raised and bucket tipped forward in a snow bank. If the weather co-operates I will take the door off and try it for awhile and see what happens, just in case.
I am trying to add as much info as I can to this post for others as well as myself that have a similar problem so keep the answers and suggestions coming.

Brian

 

[nobull1]

Old Machinist
When the new line and other parts come in this week I will just have to make a judgement call of what to use. You made a point by saying is it rated for diesel? Good question as I know it is rated for gas and I just never thought about diesel, probably is but I will investigate further. I will try to use a magnet as you suggested, regardless. If I can fish it out good if not well, I tried.
Ken
Time fly's when your having fun, yeah right, about a year since we talked.
You might know since I returned a few weeks ago, I now have issues. All was well for the last year or so, now pow.
Anyhow I was thinking possibly lift pump as well until I removed the grommet at the tank and found no hose on the end of the ninety. I was somewhat careful removing the grommet and no way would I have broken an intact hose off. The remaining hose on the ninety was semi soft, not brittle and must have been at least partially broke IMO and sucking air. I believe the hose must have been there or it would not have worked with half a tank of fuel just before I took it apart. The other reason I was thinking it wasn't the pump was after it stalled the primer bulb was not collapsed and when I squeezed it for the first few pumps there was no fuel in it. I didn't think that a bad pump would allow air to be in the primer bulb? I could be wrong though and await your answer. The other thing is I do not know the mechanics of those lift pumps and wonder if they could be intermittent or if they would slowly pump less. Maybe you know and can educate me. The other reason I now think it isn't the pump is since replacing the line the machine has worked fine (at least yesterday) and “appeared” to have more power when under load. All I can do is keep trying it and see if the problem arises again. Last two times it happened I was almost trapped in the machine with the door on and the loader raised and bucket tipped forward in a snow bank. If the weather co-operates I will take the door off and try it for awhile and see what happens, just in case.
I am trying to add as much info as I can to this post for others as well as myself that have a similar problem so keep the answers and suggestions coming.

Brian

OK today I was talking with an employee of mine and we were wondering if the rubber fuel line was designed for fuel to be outside the line as with a fuel tank pickup line. Well after a little searching I found that the most common type of fuel line is sae j30r7 which has a coating on the inside of the hose but none outside. So continuing to use the hose I am using will probably mean it will just go soft and maybe even contaminate the fuel as well. The proper hose is a sae j30r10 which nobody has and is expensive. So I am still waiting for the Bobcat replacement parts and will see what they look like. Just wondering if they are still using the soft plastic or hard?

 

[Tazza]

OK today I was talking with an employee of mine and we were wondering if the rubber fuel line was designed for fuel to be outside the line as with a fuel tank pickup line. Well after a little searching I found that the most common type of fuel line is sae j30r7 which has a coating on the inside of the hose but none outside. So continuing to use the hose I am using will probably mean it will just go soft and maybe even contaminate the fuel as well. The proper hose is a sae j30r10 which nobody has and is expensive. So I am still waiting for the Bobcat replacement parts and will see what they look like. Just wondering if they are still using the soft plastic or hard?

The last one i got from the dealer was soft plastic.
I have used i think gates hose, i know it was a quality name in my 743. Been in my fuel tank for 6 years, still no issues.

 

[nobull1]

The last one i got from the dealer was soft plastic.
I have used i think gates hose, i know it was a quality name in my 743. Been in my fuel tank for 6 years, still no issues.

Tazza
The proper hose is like $20.00 a foot so not likely that was what you used, or you would probably remember. The sae # is on all the different pieces of hoses I have seen. If you look up the numbers on Google that I posted above you can see what the uses are. All that being said I wouldn't be surprised that a regular hose could hold up six years and maybe many more. I am going to pull the grommet tomorrow and install a piece of stainless wire around the top of the hose where it attachés to the elbow just to make sure it doesn't fall off. Although it has been only a week I am curious to see what the outside of the hose looks like. I really don't want to be out in -20 weather in the middle of the yard with a flashlight trying to install a new hose if you know what I mean. My busiest time of the year for my machine is when nobody wants to be outdoors when it's snowing and freezing. More info to follow.

 

[Tazza]

Tazza
The proper hose is like $20.00 a foot so not likely that was what you used, or you would probably remember. The sae # is on all the different pieces of hoses I have seen. If you look up the numbers on Google that I posted above you can see what the uses are. All that being said I wouldn't be surprised that a regular hose could hold up six years and maybe many more. I am going to pull the grommet tomorrow and install a piece of stainless wire around the top of the hose where it attachés to the elbow just to make sure it doesn't fall off. Although it has been only a week I am curious to see what the outside of the hose looks like. I really don't want to be out in -20 weather in the middle of the yard with a flashlight trying to install a new hose if you know what I mean. My busiest time of the year for my machine is when nobody wants to be outdoors when it's snowing and freezing. More info to follow.

I'll have to look, i haven't used the hose yet. Its for a machine that is still under construction. Its with my stock pile of parts. Pretty sure it was clear plastic too, that made me doubt it would hold up actually.

 

[nobull1]

I'll have to look, i haven't used the hose yet. Its for a machine that is still under construction. Its with my stock pile of parts. Pretty sure it was clear plastic too, that made me doubt it would hold up actually.

Late this afternoon I received a call from Bobcat saying my parts are in. I rushed over and picked them up and began removing the gas line I had installed last week. The hose looked perfect with no sign of deterioration, it was only a week though. The new Bobcat parts were a filter/check valve, piece of semi soft clear gas line and two clamps. I made a judgement call and decided to go with the Bobcat parts for a couple of reasons. One reason was the line from Bobcat was the proper thing that they use on their machines as opposed to my line that the manufacturer says shouldn't be used for submersion. Another reason was the clamps to hold the filter and hose to the ninety seemed like the perfect fit for a tight fitting hose. If I used the black gas line I would have had to use stainless wire due to the limited space. I also decided to use the filter at the end of the gas line for a couple of reasons. One reason was it's a filter with a large surface area so it should take quite a bit to block it. Another is the grommet on my machine is easy to get out and cleaning/ removing the filter if it becomes a problem is not a hard job. I did order a spare grommet just in case though. I measured the depth to the bottom of the tank and found the new Bobcat line with the filter/check valve would be resting on the bottom of the tank. I figure that was not a good idea in my case. The old hose I was not able to get out of the tank so I thought a inch or so from the bottom was a better idea as I never run my machine low on fuel regardless. This summer I will run the tank low and drain to see how much material is in the tank as well as to try and remove the old hose. Anyhow it means I will periodically take a look just to see what condition the hose is in and replace for a minimal amount of money every few years if needed, before it breaks. I still think a solid vinyl/ plastic line of some sort is the best but as of yet have not found what I think I need, and winter is here.