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Discussion Starter · #1 ·
My 318 has run great , a little hard starting but it will start. I must confess I thought the hard starting was due to a weak fuel pump on start up only. I heard of a small trick to mount a squeeze bulb ( like used on an out board) in the gas line. This really helped the issue on start up for the last couple of years. Now a new issue has started . The 318 starts and runs for a while 2- 5 minutes and will just kill , not starve for gas before dyeing, but just kill. Then it will not start until sitting for a while . The only thing that was done differently in the operation of the unit, is last time while blowing snow, I switched the gas valve, the one that has the reserve setting , to reserve . I have never done this before on this tractor. I did it because I knew I was getting down there on gas and wanted to finish the job with no issue , which I did . Since I refilled the tank with good fresh gas and reset the valve to the normal run positions the issue started. Any ideas what could be causing this problem? I believe this 318 has the electronic ignition. , Thank You.
 

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Have you ever replaced the fuel line and in tank lines/fittings?
They are known to rot away. If this happened, which is extremely likely, you could have sucked a piece into the line causing a partial blockage and starving the engine for fuel.
The other issue may be a coil going bad, and just a coincidence of the fuel selector valve.

The tank fix isnt too hard, but you do need to remove the fender deck.
When I did mine (write up over on Weekend Freedom Machines) I replaced the fuel line from the engine all the way back, both tank grommets, and all hard lines/filters/etc inside the tank. The fuel line I used in the tank was Tygon.
I also took that opportunity to clean the tank out really well. 30 plus years of use leads to some crud in the tank.

Mine only takes a bit of cranking when its sat for a long time, like several weeks without use.
Then it likes lots of choke, and a bit of cranking, but always fires off.
Ive read about the fuel bulb thing some guys do, but it seems like it would take about as much time to open the hood, give it a few squeezes and close it as it would to pull the choke and just let it crank for a few, so I never saw the upside.
 

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Discussion Starter · #3 ·
Have you ever replaced the fuel line and in tank lines/fittings?
They are known to rot away. If this happened, which is extremely likely, you could have sucked a piece into the line causing a partial blockage and starving the engine for fuel.
The other issue may be a coil going bad, and just a coincidence of the fuel selector valve.

The tank fix isnt too hard, but you do need to remove the fender deck.
When I did mine (write up over on Weekend Freedom Machines) I replaced the fuel line from the engine all the way back, both tank grommets, and all hard lines/filters/etc inside the tank. The fuel line I used in the tank was Tygon.
I also took that opportunity to clean the tank out really well. 30 plus years of use leads to some crud in the tank.

Mine only takes a bit of cranking when its sat for a long time, like several weeks without use.
Then it likes lots of choke, and a bit of cranking, but always fires off.
Ive read about the fuel bulb thing some guys do, but it seems like it would take about as much time to open the hood, give it a few squeezes and close it as it would to pull the choke and just let it crank for a few, so I never saw the upside.
Hi Jim, sorry for the late response . Replacing the fuel line sounds like a great idea. Not sure if it has ever been done as I bought the 318 from a guy who " flips" them. The engine was a rebuild as it was called and I must admit besides normal things I believe it is in good working order, no leaks , no smoke , no burning of oil ( maybe a bit) . This summer would be a good time to take a better look at the replacing of the gas line. A retired friend (mechanic) of mine called this morning to shoot the breeze and I asked him about the problem. He said it could be a coil that craps out when it gets warm. According to him the way to check that is as follows. When the motor dies , have access to removing a plug and ground it out, crank over the engine to see of there is spark on the plug. Not sure about this , but also worth a try. I do have a very good in line gas filter in the line before it enters the carb so maybe I can also check to see how the gas flow is through there. I sure do appreciate your suggestion and Thank You so much for your response. Any Others?
 

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Hi Jim, sorry for the late response . Replacing the fuel line sounds like a great idea. Not sure if it has ever been done as I bought the 318 from a guy who " flips" them. The engine was a rebuild as it was called and I must admit besides normal things I believe it is in good working order, no leaks , no smoke , no burning of oil ( maybe a bit) . This summer would be a good time to take a better look at the replacing of the gas line. A retired friend (mechanic) of mine called this morning to shoot the breeze and I asked him about the problem. He said it could be a coil that craps out when it gets warm. According to him the way to check that is as follows. When the motor dies , have access to removing a plug and ground it out, crank over the engine to see of there is spark on the plug. Not sure about this , but also worth a try. I do have a very good in line gas filter in the line before it enters the carb so maybe I can also check to see how the gas flow is through there. I sure do appreciate your suggestion and Thank You so much for your response. Any Others?
Replacing the fuel line is a good idea.

You can get an inline spark checker for around $10 so you just have to open the hood to see it’s sparking.



Lisle 20610 Inline Spark Tester https://www.amazon.com/dp/B0002STSC6/ref=cm_sw_r_cp_api_glt_fabc_4NMQEFC12Y2NKKJGFA45

Is this a b43 or p-218 engine?
 
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When you crank it and it won't start. When you stop cranking does it seem to fire a little? If it's stopping dead and not acting like it's running out of fuel, it's likely not a fuel problem.
I'd be looking at electrical, check the coil resistance when it's cold and hot. Have a look at the ignition switch for loose wires and corrosion and then you are looking at a bad condenser or the ever popular ignition trigger.
 
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Discussion Starter · #6 ·
Replacing the fuel line is a good idea.

You can get an inline spark checker for around $10 so you just have to open the hood to see it’s sparking.



Lisle 20610 Inline Spark Tester https://www.amazon.com/dp/B0002STSC6/ref=cm_sw_r_cp_api_glt_fabc_4NMQEFC12Y2NKKJGFA45

Is this a b43 or p-218 engine?
It is a P218 engine. I checked your tip on the inline spark tester. I followed the link on Amazon and they want to know for what vehicle. Could you recommend which one I should state on the order so I get the right one? Or will any one work ? Thank You for your suggestions too. I am by far a mechanic but do know which end of a wrench to hold. Thanks Again
 

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That’s actually a check to make sure it will fit, not different models of tester. You should be able to just buy it now.
 

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Discussion Starter · #9 ·
When you crank it and it won't start. When you stop cranking does it seem to fire a little? If it's stopping dead and not acting like it's running out of fuel, it's likely not a fuel problem.
I'd be looking at electrical, check the coil resistance when it's cold and hot. Have a look at the ignition switch for loose wires and corrosion and then you are looking at a bad condenser or the ever popular ignition trigger.
It does not fire at all, just cranks. After time it will pop off if I leave it sit . I’ll check your suggestions when I can get back at it. Ignition trigger?
 

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The ignition trigger hides behind the flywheel. I’d check everything else first.
 
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There’s a service manual download available here.


Section 10-1 step #5 describes testing the timing module. I’m not sure how definitive this is with an intermittent failure.

ChuckV may stop by with more help.
 

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Discussion Starter · #12 ·
There’s a service manual download available here.


Section 10-1 step #5 describes testing the timing module. I’m not sure how definitive this is with an intermittent failure.

ChuckV may stop by with more help.
Thank You, I have , what I believe is that manual downloaded and in my "Tractor book" . I looked it over but 10-1 has mostly to do with Engine Disassembly. Maybe I am not following the correct order or have a different manual. The Heading of the manual says Onan Engine Service Manual P216,P218,P220,P224. I did order the spark tester. Should be here tomorrow. I really almost think buying a new coil may be a cheap fix (if it corrected the problem) and if not , I would at least know I have a new coil on the 318. I am kind of stuck in the house here , doctors orders , but may sneak over to the shed and look for the placement of the coil on the motor . Maybe I'll look through my books to see any diagrams of the location too. Like I said I am not a mechanic but willing to learn. Thanks again
 

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DaSu,

Here is an excerpted illustration on testing the ignition module for a P-series Onan that might be helpful:
Jaw Font Parallel Elbow Rectangle


Chuck
 

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I was waiting for Chuck. We are just a few tests away from the picture I remember by the stator. (y)
 

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Discussion Starter · #17 ·
Replacing the fuel line is a good idea.

You can get an inline spark checker for around $10 so you just have to open the hood to see it’s sparking.



Lisle 20610 Inline Spark Tester https://www.amazon.com/dp/B0002STSC6/ref=cm_sw_r_cp_api_glt_fabc_4NMQEFC12Y2NKKJGFA45

Is this a b43 or p-218 engine?
I am not sure how to post pictures on here but I did receive my light tester today. Backing up, yesterday I pulled the air cleaner and side skirts from around the motor. Tried starting it and it popped off but killed in a minute or longer. Today with the new light tester hooked up in line , I tried starting it and there is no light sparking ,indicating no spark from coil. I thought , just to test the new light tester I hooked it up to my JD L108. Upon cranking over the 108 , the light flashed repeatedly. So now am I correct to assume that my coil is bad , going bad? I am wondering if this is the case , why sometimes before this recent issue the 318 was “hard to start” , meaning it would just crank at times and eventually pop. Am I barking up the right tree or close to it?
 

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Do you have a multi meter?

It appears you don’t have spark, now we can find out why. The coil is one of many possibilities
 

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Discussion Starter · #20 ·
Do you have a multi meter?

It appears you don’t have spark, now we can find out why. The coil is one of many possibilities
Yes I do ,but only have the rights to say I own one but not really sure how to use it🤪.
 
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