New memeber looking for help. 642 won't restart when warm.

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showtime

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Hey I hope this site is my savior it seams there is alot of knowledge on it. Anyway my issue is my first bobcat a 642 with a ford industrial engine is giving me a little issue. Once the unit is up to operating temps for 10-15min if I shut it off it won't re-start? It will run great all day once it is running if i don't shut it off. If I let it sit for 30min or so till it really cools down then it will start. I don't see anywhere where the gas line is getting cooked to cause a vapor lock condition where do I go now?? What is the fuel shut off gizzmo on the gas line for?? If I remove the gas cap or change the fuel level none of these seam to help the problem? Thanks for any help!
 

Tazza

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All i can think of is to check your leads/plugs/distributor cap/rotor/condenser. Basically all the ignition side of things. Maybe the ignition coil. I was told the spark should be blue not yellow. If its giving orange sparks its a sign of a weak ignition coil or leads. This will cause hard starting too but not only when warm.
If that fails, it may be something with the choke, it may be flooding the engine when warm, when its warm it doesn't need the extra fuel and *may* be causing your problems.
 

Tazza

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All i can think of is to check your leads/plugs/distributor cap/rotor/condenser. Basically all the ignition side of things. Maybe the ignition coil. I was told the spark should be blue not yellow. If its giving orange sparks its a sign of a weak ignition coil or leads. This will cause hard starting too but not only when warm.
If that fails, it may be something with the choke, it may be flooding the engine when warm, when its warm it doesn't need the extra fuel and *may* be causing your problems.
One other thing you could try.
When its warm, try starting it with a snort of ether, if it starts or wants to start its a fuel problem. If its exactly the same it has to be an electrical problem.
Good Luck!
 

showtime

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One other thing you could try.
When its warm, try starting it with a snort of ether, if it starts or wants to start its a fuel problem. If its exactly the same it has to be an electrical problem.
Good Luck!
I have gave it starting fluid when this happens and it still won't go. So maybe electrical.
 

jerry

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Does anyone know what the electronic fuel shut off is for on the gas line in between the tank and carb? thanks
the fuel valve on the line is just that. It is a electrically operated soleniod that opens the valve when you turn on the ignition key. A bad condenser or coil will show up with engine heat and cause spark to fail but if it runs well hot just won't restart it makes you wonder. Try a different coil first if you have one lying around. Then condenser. Some engines will run with a weak spark but will not start.
 

jerry

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the fuel valve on the line is just that. It is a electrically operated soleniod that opens the valve when you turn on the ignition key. A bad condenser or coil will show up with engine heat and cause spark to fail but if it runs well hot just won't restart it makes you wonder. Try a different coil first if you have one lying around. Then condenser. Some engines will run with a weak spark but will not start.
The next time it won't start take #1 plug wire and put a spare plug in it and lay it on the manifold and watch for spark when cranking engine. If you have to do it alone turn ignition on and jump the starter soleniod or use a remote switch. You could check the fuel soleniod by disconnecting the line ahead of the fuel pump( on my 632 it is a rubber line here) and turning on ignition switch but if the engine is hot it would not be safe. Maybe crank it over with the choke on, if the plugs get wet you have fuel. If there is fuel and spark check compression next.
 

showtime

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The next time it won't start take #1 plug wire and put a spare plug in it and lay it on the manifold and watch for spark when cranking engine. If you have to do it alone turn ignition on and jump the starter soleniod or use a remote switch. You could check the fuel soleniod by disconnecting the line ahead of the fuel pump( on my 632 it is a rubber line here) and turning on ignition switch but if the engine is hot it would not be safe. Maybe crank it over with the choke on, if the plugs get wet you have fuel. If there is fuel and spark check compression next.
Hey guys I worked on it tonight and found somthing. I got it up to operating temp did some work as normal then let it sit. When I went to re start a minute or two later same old deal no start. Then I put a Kids medical cold pack on the electronic fuel shut off for a few minutes the BINGO it poped right off! Then I repeated this whole process twice and got the same results, when hot no start when put on ice pops right off. I think that may be the culprit?
 

Tazza

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Hey guys I worked on it tonight and found somthing. I got it up to operating temp did some work as normal then let it sit. When I went to re start a minute or two later same old deal no start. Then I put a Kids medical cold pack on the electronic fuel shut off for a few minutes the BINGO it poped right off! Then I repeated this whole process twice and got the same results, when hot no start when put on ice pops right off. I think that may be the culprit?
Looks like you found it.
You could try and by-pass it and see if it stops again. I think the fuel cut just prevents fuel from evaporating when the machine is not in use. I don't “think” its really needed as when you turn the key off it stops power going to the ignition coil. But if you notice the machine seems “fumy” when it sits you may need to fit a new fuel cut solenoid.
Glad you hopefully found the problem.
 

jerry

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Looks like you found it.
You could try and by-pass it and see if it stops again. I think the fuel cut just prevents fuel from evaporating when the machine is not in use. I don't “think” its really needed as when you turn the key off it stops power going to the ignition coil. But if you notice the machine seems “fumy” when it sits you may need to fit a new fuel cut solenoid.
Glad you hopefully found the problem.
That is a good way to check those coil operated controls, I learn something everytime I read this forum, now if I could just remember it when I need it
 
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