732 rough running, backfiring

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GILL

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Dec 1, 2005
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I've got a older 732 with the Ford engine. It has run fine since the last problems in '05. Now, it acts like it has run out of gas and the engine dies. It will restart immediately then die after a couple of seconds. If you wait a while it seems to come out of it somewhat yet, still die. When you get it running again sometimes when you advance throttle it dies. Yesterday, it ran fine for over an hour then this all started again, and, it was backfiring before it died. I advanced throttle 100% then it started and ran fine enough to finish the job and get it to the shed. This has been happening off and on for a couple of weeks. Before that it ran fine as long as you kept fuel in the tank. Any ideas? I have done no actual changes since '05 when I replaced plugs, etc. Thanks in advance Greg
 

Hotrod1830

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check your point gap, vacuum advance and timing first.
Inspect the points and condenser, replace if unknown when it was last done. Fuel filter? I had one once that acted like it was running out of fuel, same symptoms as yours. Chased my tail for weeks trying to find it. ended up being a failing ignition coil.
 
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GILL

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Inspect the points and condenser, replace if unknown when it was last done. Fuel filter? I had one once that acted like it was running out of fuel, same symptoms as yours. Chased my tail for weeks trying to find it. ended up being a failing ignition coil.
All, I checked the condition of the points and rotor last night. I have both of them new on hand and the old stuff looks good. I will check the point gap next and see what the plugs look like. I can't see any places where the plug wires are arcing or anything like that. It's been about 98-100* here and have been limiting my time on this to the cooler evening hours. Tonight or tomorrow I'll blow the dirt etc. away from the plug bases and set up my remote starter and just see what type of spark I have. I've have new plugs on hand since '05. The fuel filter is getting old and I will change it just because. I'll get back to you guys. Thanks Greg
 

OldMachinist

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All, I checked the condition of the points and rotor last night. I have both of them new on hand and the old stuff looks good. I will check the point gap next and see what the plugs look like. I can't see any places where the plug wires are arcing or anything like that. It's been about 98-100* here and have been limiting my time on this to the cooler evening hours. Tonight or tomorrow I'll blow the dirt etc. away from the plug bases and set up my remote starter and just see what type of spark I have. I've have new plugs on hand since '05. The fuel filter is getting old and I will change it just because. I'll get back to you guys. Thanks Greg
Maybe vapor lock with it being that hot.
 

craigb93

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Nov 9, 2010
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Maybe vapor lock with it being that hot.
The engine camshaft lobe that actuates the fuel pump is prone to wear. Couple that with the fact that ethanol in the fuel seems to make the fuel pump diaphragm get hard as a rock in short order. I replaced the pump twice in a year and gave up. Installed an electric pump and have not looked back in 3-years
 
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GILL

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The engine camshaft lobe that actuates the fuel pump is prone to wear. Couple that with the fact that ethanol in the fuel seems to make the fuel pump diaphragm get hard as a rock in short order. I replaced the pump twice in a year and gave up. Installed an electric pump and have not looked back in 3-years
craigb93' How did you determine the lobe was worn? By feel or something? If I decided to change to a electric pump, can you tell me where you got it and how you hooked it up? Did you need a return line for excess fuel or anything? I'm guessing you would have to make a plate to cover hole in block and then make up a gasket? What gets me interested in this is the fact that a couple of weeks before this latest episode the engine would not start. I guessed it was not getting gas so I pulled the air filter out and used some ether. It started immediately and then died as the ether ran out. A couple more tries and it started and then ran fine. I've never had that type of problem before. Thanks Greg
 
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GILL

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craigb93' How did you determine the lobe was worn? By feel or something? If I decided to change to a electric pump, can you tell me where you got it and how you hooked it up? Did you need a return line for excess fuel or anything? I'm guessing you would have to make a plate to cover hole in block and then make up a gasket? What gets me interested in this is the fact that a couple of weeks before this latest episode the engine would not start. I guessed it was not getting gas so I pulled the air filter out and used some ether. It started immediately and then died as the ether ran out. A couple more tries and it started and then ran fine. I've never had that type of problem before. Thanks Greg
All, While I'm asking all these questions on this engine problem, does anyone know of a reasonbly priced muffler for the Ford? I checked with Bobcat and as I recall it was expensive. I wonder if a muffler shop could fashion one by cutting and welding an existing muffler? Greg
 

Tigerhaze

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Nov 3, 2011
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craigb93' How did you determine the lobe was worn? By feel or something? If I decided to change to a electric pump, can you tell me where you got it and how you hooked it up? Did you need a return line for excess fuel or anything? I'm guessing you would have to make a plate to cover hole in block and then make up a gasket? What gets me interested in this is the fact that a couple of weeks before this latest episode the engine would not start. I guessed it was not getting gas so I pulled the air filter out and used some ether. It started immediately and then died as the ether ran out. A couple more tries and it started and then ran fine. I've never had that type of problem before. Thanks Greg
Hi Gill-
I have read a lot of posts on this site and others about using an electric fuel pump and am getting ready to install them myself on my 610 and 630 Bobcat skid steers. I believe that many people leave the mechanical fuel pump installed and install the electric fuel pump in series in front of the mechanical fuel pump to give it a boost. I have also read that if you do that, it is imperative to get a fuel pressure regulator (sold at auto parts stores along with the pump) to keep pressure down as the Wisconsin VH4D's supposedly work best on 2-4 psi. It may be a different pressure setting for your Ford engine. Obviously this approach will not work if your mechnical pump is leaking, so I would like to hear as well whether others have taken off the mechanical pump and installed a block plate.
I am also planning to wire the fuel pump to a separate fused push/pull switch near my seat rather than through the ingition switch- the idea being that it can serve as an emergency cutoff if the machine were to roll or otherwise get out of control. What do others think of that idea?
 

OldMachinist

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Hi Gill-
I have read a lot of posts on this site and others about using an electric fuel pump and am getting ready to install them myself on my 610 and 630 Bobcat skid steers. I believe that many people leave the mechanical fuel pump installed and install the electric fuel pump in series in front of the mechanical fuel pump to give it a boost. I have also read that if you do that, it is imperative to get a fuel pressure regulator (sold at auto parts stores along with the pump) to keep pressure down as the Wisconsin VH4D's supposedly work best on 2-4 psi. It may be a different pressure setting for your Ford engine. Obviously this approach will not work if your mechnical pump is leaking, so I would like to hear as well whether others have taken off the mechanical pump and installed a block plate.
I am also planning to wire the fuel pump to a separate fused push/pull switch near my seat rather than through the ingition switch- the idea being that it can serve as an emergency cutoff if the machine were to roll or otherwise get out of control. What do others think of that idea?
I'd take the mechanical pump off and install a plate. If you leave the old pump there and the diaphragm goes bad it might leak into the crankcase.

If you're going to wire in a E-Stop switch I'd just run the ignition thru it. If you just turn off the electric fuel pump the engine will still run until the carburetor bowl is empty.
 

jerry

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I'd take the mechanical pump off and install a plate. If you leave the old pump there and the diaphragm goes bad it might leak into the crankcase.

If you're going to wire in a E-Stop switch I'd just run the ignition thru it. If you just turn off the electric fuel pump the engine will still run until the carburetor bowl is empty.
There should already be a fuel solenoid shutoff on the fuel line on the firewall before the fuel pump that is activated by the ignition switch, maybe you can get power there for the pump.
 

craigb93

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There should already be a fuel solenoid shutoff on the fuel line on the firewall before the fuel pump that is activated by the ignition switch, maybe you can get power there for the pump.
I've posted this before but typing is easier than finding the old post. My electric pump is a Carter P4070. It is connected directly between the fuel shut-off solenoid and the anti-diesel solenoid @ the carb. I ran a #12 wire from the battery through a 10 amp fuse to a power relay, then to the pump . A connection from the coil primary post provides trigger voltage to the relay. Wiring diagram is printed on the relay box (cost $8.00 @ Autozone). Removed the original pump and added a block off plate. The poor condition of my cam lobe was as seen with a mirror and flashlight with the pump off. In the US, Summit Racing sells the pumps on-line. I also bought a Holly 12-804 Pressure regulator but have not opened the box. I have a muffler for a Bobcat 742 that is very good if someone wants one for $50 plus postage. -Dick
 
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GILL

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I've posted this before but typing is easier than finding the old post. My electric pump is a Carter P4070. It is connected directly between the fuel shut-off solenoid and the anti-diesel solenoid @ the carb. I ran a #12 wire from the battery through a 10 amp fuse to a power relay, then to the pump . A connection from the coil primary post provides trigger voltage to the relay. Wiring diagram is printed on the relay box (cost $8.00 @ Autozone). Removed the original pump and added a block off plate. The poor condition of my cam lobe was as seen with a mirror and flashlight with the pump off. In the US, Summit Racing sells the pumps on-line. I also bought a Holly 12-804 Pressure regulator but have not opened the box. I have a muffler for a Bobcat 742 that is very good if someone wants one for $50 plus postage. -Dick
To All, Thanks for all your suggestions and info so far. I'm still waiting for the filter to come in. Once I get that I'm going to try rounding up a pressure gauge and check the fuel pump. Last night I pulled the plugs and they looked fine. They were all a light tan color and had a decent spark. I closed shed door to get it darker in there and I would say they had plenty of spark. I used a new plug on one cylinder and the spark looked the same to me. I'm also going to try to borrow a timing light and check that also. I did a cold compression test and all but one cylinder were in the 145 to 155# range. The odd one was at 90# but, the o-ring on my tester was shot by then and I'm not sure I got a good reading. I'll replace it and try again. I'll update as I try things. Greg
 

jerry

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To All, Thanks for all your suggestions and info so far. I'm still waiting for the filter to come in. Once I get that I'm going to try rounding up a pressure gauge and check the fuel pump. Last night I pulled the plugs and they looked fine. They were all a light tan color and had a decent spark. I closed shed door to get it darker in there and I would say they had plenty of spark. I used a new plug on one cylinder and the spark looked the same to me. I'm also going to try to borrow a timing light and check that also. I did a cold compression test and all but one cylinder were in the 145 to 155# range. The odd one was at 90# but, the o-ring on my tester was shot by then and I'm not sure I got a good reading. I'll replace it and try again. I'll update as I try things. Greg
If you have a vacuum gauge most of them are also fuel pump pressure gauge. Is the point gap right? And there is a mechanical spark advance in the distributer too. It could be fuel related but the 632 I had did this and after changing everything else I found the point gap had shifted.
 
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GILL

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If you have a vacuum gauge most of them are also fuel pump pressure gauge. Is the point gap right? And there is a mechanical spark advance in the distributer too. It could be fuel related but the 632 I had did this and after changing everything else I found the point gap had shifted.
Well so far I've changed the plugs, points, condenser and rotor. I set the points to the gap in my bobcat book and put it all back together. It started easily as always and seemed to run o.k. I shut it down to tighten up fuel filter since it was dripping and then restarted with timing light installed. In the book it shows three marks on pulley but, I only have one cut on mine. The timing seemed way off by a couple of inches on the pulley. When I tried to adjust to tdc it caused the engine to run rough and die. So I rotated the distributor back and got it running again like it was. Now it seems to be running out of gas again. The longer I let it sit the longer it will run. Is it possible the fuel pump is bad (like was brought up before) and the fuel is getting by it and getting just enough gas to carb to allow it to run? There are two solenoids but it seems to get some gas. What do you guys think Thanks Greg
 

Hotrod1830

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Well so far I've changed the plugs, points, condenser and rotor. I set the points to the gap in my bobcat book and put it all back together. It started easily as always and seemed to run o.k. I shut it down to tighten up fuel filter since it was dripping and then restarted with timing light installed. In the book it shows three marks on pulley but, I only have one cut on mine. The timing seemed way off by a couple of inches on the pulley. When I tried to adjust to tdc it caused the engine to run rough and die. So I rotated the distributor back and got it running again like it was. Now it seems to be running out of gas again. The longer I let it sit the longer it will run. Is it possible the fuel pump is bad (like was brought up before) and the fuel is getting by it and getting just enough gas to carb to allow it to run? There are two solenoids but it seems to get some gas. What do you guys think Thanks Greg
#1 cylinder is on the Flywheel side. You really need to get a fuel pressure gauge on it. If you dont have one, Run a long piece of fue line from the pump to carb, with a barbed connecter in the middle. Make it long enough to run outside the engine compartment. Wit hit running and acting like it is running out of fuel, pull the fuel line apart at the barbed fitting. You should get alot of fuel pumping. If it just trickled out you have a bad pump or restriction from tank to pump. I say to do this outside the engine compartment because if you get fuel on the distributor, it can ignite it. Be safe... Oh, and make sure the fuel cap is venting. Remove the fuel cap when it is acting up. see if it cleares up.
 
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GILL

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#1 cylinder is on the Flywheel side. You really need to get a fuel pressure gauge on it. If you dont have one, Run a long piece of fue line from the pump to carb, with a barbed connecter in the middle. Make it long enough to run outside the engine compartment. Wit hit running and acting like it is running out of fuel, pull the fuel line apart at the barbed fitting. You should get alot of fuel pumping. If it just trickled out you have a bad pump or restriction from tank to pump. I say to do this outside the engine compartment because if you get fuel on the distributor, it can ignite it. Be safe... Oh, and make sure the fuel cap is venting. Remove the fuel cap when it is acting up. see if it cleares up.
Hotrod thanks for your reply. My book shows the #1 cylinder to be at the opposite end than what you're saying. I show the distributor on the l/h side if facing the fan end ( I assume the waterpump end end). I'm going to check with a Bobcat dealer and see what they say. I have borrowed a fuel pressure gauge and will try what you say on the "T" fitting to check pressure. Thanks Greg
 

jerry

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Hotrod thanks for your reply. My book shows the #1 cylinder to be at the opposite end than what you're saying. I show the distributor on the l/h side if facing the fan end ( I assume the waterpump end end). I'm going to check with a Bobcat dealer and see what they say. I have borrowed a fuel pressure gauge and will try what you say on the "T" fitting to check pressure. Thanks Greg
You know you have to disconnect and plug the vacuum hose to the vacuum advance when setting the timing? otherwise it will appear to be way off. Just a thought.
 

Hotrod1830

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You know you have to disconnect and plug the vacuum hose to the vacuum advance when setting the timing? otherwise it will appear to be way off. Just a thought.
Good point about the vacuum hose Jerry.
I have the Ford 1.6 in the 632, and I will assume they didnt change the firing order or cylinder numbering between models. I thought as well that number one was on the front on mine, and I tried to install new plug wires. Never did start. Finally looked at my manual and figured out number one was at the back. Fired up first try after that correction. It would explain the timing marks being so far off. Hook the timing light up to the front cylinder, remove and plug the vacuum hose and check timing at idle. If it is still way off, hook the light up to the rear cylinder. It is a Ford after all, I guess they could have made them different.
If you got ahold of a pressure gauge, no need to remove the hose while its runing, just tee into the line and check fuel pressure when its acting up. If theres a problem, itll have almost zero pressure, otherwise I think the spec it 4-5 psi..
 

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