I wonder if my glow plug or pre-heat system is really working.

   / I wonder if my glow plug or pre-heat system is really working. #1  

prs

Platinum Member
Joined
Apr 30, 2014
Messages
700
Location
Logan, WV
Tractor
JD 650, Ventrac 4500Z AJ02248
My 33 year-old JD 650 just keeps on keeping on. In the distant past I was able to hear a little "pop" in the manifold when the glow plug activated some fuel, but past few years that "pop" has been absent. So, in beginning my winter prep yesterday ahead of snow season, I decided to trouble shoot it. I grounded my volt meter, but the positive probe on the plugs connecter and turned the ignition switch to pre-heat position. I got full battery voltage reading at first (13.35V) and that voltage dropped rather quickly as I continued to hold the switch closed for 45 seconds (12.2). So I reckon the plug is drawing a good bit of current, but still no "pop". It was not very cold yesterday, upper 30sF as I was testing. I got on the tractor and cycled the glow plug again and started the tractor. It fired right up, but that tractor almost always fires right up without the plug assist unless it is in the 20sF. So I wonder if the pre-heater fuel feed to the manifold is working and how to check it or service it.

prs
 
   / I wonder if my glow plug or pre-heat system is really working. #2  
prs,

I'll be watching this thread with interest. This summer I picked up this 1985 JD650 to use fall and spring moving boats around our storage barn. The temperature of the morning that the attached picture was taken was 24F. The tractor started right up after cycling the glow plug/fuel burn system. It ran rough for a bit, but ironed out OK. I'm real happy with this tractor and hope to give it another 20 or 30 years of use! I would like to know if the system is working properly.

Frank

JD650 at work.jpg
 
   / I wonder if my glow plug or pre-heat system is really working. #3  
There are several way to determine if the glow plugs are drawing current. I have a simple inductive coupled current meter I would place over the wire feeding the glow plugs and measure the current that way. You could use a thermal heat sensor gun to measure the temp rise on each glow plug. You could measure the voltage on the glow plug rail, then if you remove the rail and do a resistance check of each glow plug to the engine block you could be pretty assured that they are working.
 
   / I wonder if my glow plug or pre-heat system is really working. #4  
James,

I think PRS is pretty confident that current is being used by the glow plug of the "Thermo start system" (I think that is what it was called in the 1985 Owner's Manual for the JD650), but he is unsure if the small amount of diesel fuel is being ignited at the manifold to warm the components. My manual is put away at our camp for the winter- I won't be able to check it until the spring. However, I was also wondering how to check the fuel part of this older system?

Thanks.

Frank
 
   / I wonder if my glow plug or pre-heat system is really working. #5  
James,

I think PRS is pretty confident that current is being used by the glow plug of the "Thermo start system" (I think that is what it was called in the 1985 Owner's Manual for the JD650), but he is unsure if the small amount of diesel fuel is being ignited at the manifold to warm the components. My manual is put away at our camp for the winter- I won't be able to check it until the spring. However, I was also wondering how to check the fuel part of this older system?

Thanks.

Frank

Aha, I see that now that you mention it.:)
 
   / I wonder if my glow plug or pre-heat system is really working. #6  
My 33 year-old JD 650 just keeps on keeping on. In the distant past I was able to hear a little "pop" in the manifold when the glow plug activated some fuel, but past few years that "pop" has been absent. So, in beginning my winter prep yesterday ahead of snow season, I decided to trouble shoot it. I grounded my volt meter, but the positive probe on the plugs connecter and turned the ignition switch to pre-heat position. I got full battery voltage reading at first (13.35V) and that voltage dropped rather quickly as I continued to hold the switch closed for 45 seconds (12.2). So I reckon the plug is drawing a good bit of current, but still no "pop". It was not very cold yesterday, upper 30sF as I was testing. I got on the tractor and cycled the glow plug again and started the tractor. It fired right up, but that tractor almost always fires right up without the plug assist unless it is in the 20sF. So I wonder if the pre-heater fuel feed to the manifold is working and how to check it or service it. prs

Hey PRS,

Look what I found on YouTube !!!

www.youtube.com/watch?v=Wi4mV8nrfz4

A demonstration of a working Thermostart system.

Frank
 
   / I wonder if my glow plug or pre-heat system is really working. #7  
Loosen the pipe and there should be diesel comming out.
Quite common that the smal tank or pipes needs to be cleaned, if you have diesel and heath you might have a bad thermostart unit.
 
   / I wonder if my glow plug or pre-heat system is really working.
  • Thread Starter
#8  
Hey PRS,

Look what I found on YouTube !!!

www.youtube.com/watch?v=Wi4mV8nrfz4

A demonstration of a working Thermostart system.

Frank

Well, who would have thunk it! Now you have heard that little "pop" noise I used to hear. I will try to replicate the video.

Loosen the pipe and there should be diesel comming out.
Quite common that the smal tank or pipes needs to be cleaned, if you have diesel and heath you might have a bad thermostart unit.

Well a big HELLO to Newfoundland! My top tank looks as clean as new with its bright red diesel. I have been thinking that the pipe or opening device might be clogged. I will investigate that if I can not duplicate the video. We are having an indian summer here and instead of working on tractors, looks like I am going to have to mow the fields again! In November no less! This time last year we had already had several snows. But, the reprieve from winter will not last and I will be in the shop again.

prs
 
   / I wonder if my glow plug or pre-heat system is really working.
  • Thread Starter
#9  
I "think" the JD part #CH15593 is the same as the Yanmar ThermoStart unit for Model 1110D which is available for $20.00 US delivered on eBay and elsewhere. So, if mine is broken beyond recovery, I can still get back to hearing that little "pop". Life is good!

prs
 
   / I wonder if my glow plug or pre-heat system is really working. #10  
I "think" the JD part #CH15593 is the same as the Yanmar ThermoStart unit for Model 1110D which is available for $20.00 US delivered on eBay and elsewhere. So, if mine is broken beyond recovery, I can still get back to hearing that little "pop". Life is good!

prs

Please let us know how it works out. I will file this away for use next spring when I am near the tractor again. Don't you just love this forum?

Frank
 
 
Top