Cub Cadet Loader/Backhoe model 7205

[Tom S]

Hi all, I have a Cub 7205 tractor with loader and backhoe. It has been working great until today. It will not start, I suspect due to the colder weather here in New England. It cranks and puffs white smoke but will not fire off. I suspect the glow plugs. I changed the fuel filter also. I know diesels are hard to start in colder weather, it has been in the mid 30's as of late. The tractor has a Mitsubishi S3L engine in it. My question is, has anyone experienced this? I am planning on changing the glow plugs, does anyone have a suggestion for the type or part number to use? I want to use a name brand like NGK or Bosch and avoid the 'off brands' available from China on Amazon. Appreciate any other tips or suggestions. Thx, Tom

 

[-CӞ]

would a block heater help?

in a pinch during a cold snap, i’ve used a heat gun to warm the engine for several minutes and coax it to life (on my Cub’s Kohler and mower’s Briggs & Stratton).
mid-30°s isn’t t h a t cold but it is cold enough to have a chilly impact!

 

[Tom S]

would a block heater help?

in a pinch during a cold snap, i’ve used a heat gun to warm the engine for several minutes and coax it to life (on my Cub’s Kohler and mower’s Briggs & Stratton).
mid-30°s isn’t t h a t cold but it is cold enough to have a chilly impact!

Appreciate the input...thank you! Sounds like a good idea.

 

[tkhoffman]

Appreciate the input...thank you! Sounds like a good idea.

Is this your first year with this tractor, in the cold?
Heres my experience with old school diesels. Not the silly v8 diesels.
Easy to check the glowplugs before purchase. Look for the glow plugs, usually a single wire or Bussbar attaching all 3. Turn the key to the point that glowplugs are activated and check for 12V on that bussbar/wire. If you got 12V proceed to pulling the Plugs out and again 12V to top of plug and grount the body, you should see the tip turn cherry red. Don't add voltage for more that 10 seconds. You'll know after about 4 seconds if its working.

Yes! Block heaters are very very helpful in under 30 temps. Even with glowplugs, my tractor is sooooo much happier after installing a Block heater. Turn it on about 2 hours before using tractor and it'll start and sound happier.
Just some more comments....
That white smoke is a sign that its trying. You may have to crank a diesel for a long while, 12 second intervals to get the cylinders warm enough to ignite.
You can try a hair dryer in the air filter for a while, then crank it. Warm air, warm cylinders are you friend

 

[Tom S]

Is this your first year with this tractor, in the cold?
Heres my experience with old school diesels. Not the silly v8 diesels.
Easy to check the glowplugs before purchase. Look for the glow plugs, usually a single wire or Bussbar attaching all 3. Turn the key to the point that glowplugs are activated and check for 12V on that bussbar/wire. If you got 12V proceed to pulling the Plugs out and again 12V to top of plug and grount the body, you should see the tip turn cherry red. Don't add voltage for more that 10 seconds. You'll know after about 4 seconds if its working.

Yes! Block heaters are very very helpful in under 30 temps. Even with glowplugs, my tractor is sooooo much happier after installing a Block heater. Turn it on about 2 hours before using tractor and it'll start and sound happier.
Just some more comments....
That white smoke is a sign that its trying. You may have to crank a diesel for a long while, 12 second intervals to get the cylinders warm enough to ignite.
You can try a hair dryer in the air filter for a while, then crank it. Warm air, warm cylinders are you friend

Thank you. I just did a resistance reading on my glow plugs. From what I've read the resistance should be about 1 ohm. I'm getting very high readings, 220 ohms, 120 ohms and 40 ohms on each of the three. I'm going to replace them. They are NGK in the machine with the part number on the body so I have a place to start as far as NGK part numbers go.

 

[tkhoffman]

Thank you. I just did a resistance reading on my glow plugs. From what I've read the resistance should be about 1 ohm. I'm getting very high readings, 220 ohms, 120 ohms and 40 ohms on each of the three. I'm going to replace them. They are NGK in the machine with the part number on the body so I have a place to start as far as NGK part numbers go.

About 90 ohms difference average between each plug. For some dumb reason, they're not in series, are they? You did an ohms reading with the plugs out?

 

[Tom S]

About 90 ohms difference average between each plug. For some dumb reason, they're not in series, are they? You did an ohms reading with the plugs out?

Yes, I did the ohm resistance reading with the plugs out of the engine block, held in my hand.

 

[Tom S]

Yes, I did the ohm resistance reading with the plugs out of the engine block, held in my hand.

Also, oddly the machine had three different model # NGK plugs installed. I'm the 3rd owner of this 20+ year machine, so no idea if they may have been changed individually or not, you'd think they would be changed all 3 in one shot. Nonetheless, I have 3 NGK 6628 on order from my local NAPA shop. They were able to look up the proper glow plug for the Mitsubishi 3SL engine series.

 

[Tom S]

Is this your first year with this tractor, in the cold?
Heres my experience with old school diesels. Not the silly v8 diesels.
Easy to check the glowplugs before purchase. Look for the glow plugs, usually a single wire or Bussbar attaching all 3. Turn the key to the point that glowplugs are activated and check for 12V on that bussbar/wire. If you got 12V proceed to pulling the Plugs out and again 12V to top of plug and grount the body, you should see the tip turn cherry red. Don't add voltage for more that 10 seconds. You'll know after about 4 seconds if its working.

Yes! Block heaters are very very helpful in under 30 temps. Even with glowplugs, my tractor is sooooo much happier after installing a Block heater. Turn it on about 2 hours before using tractor and it'll start and sound happier.
Just some more comments....
That white smoke is a sign that its trying. You may have to crank a diesel for a long while, 12 second intervals to get the cylinders warm enough to ignite.
You can try a hair dryer in the air filter for a while, then crank it. Warm air, warm cylinders are you friend

Appreciate the sound advice Tony

 

[tkhoffman]

Appreciate the sound advice Tony

See how well the new glow plugs alone work for you. I live in an area where -15 F is not uncommon. The Block heater was a great help. It was scary to commit to popping out a Freeze-out Plug to install the Heater but worth it. Keep responding as you proceed. Im curious how you make out

 

[rfunk]

Hi all, I have a Cub 7205 tractor with loader and backhoe. It has been working great until today. It will not start, I suspect due to the colder weather here in New England. It cranks and puffs white smoke but will not fire off. I suspect the glow plugs. I changed the fuel filter also. I know diesels are hard to start in colder weather, it has been in the mid 30's as of late. The tractor has a Mitsubishi S3L engine in it. My question is, has anyone experienced this? I am planning on changing the glow plugs, does anyone have a suggestion for the type or part number to use? I want to use a name brand like NGK or Bosch and avoid the 'off brands' available from China on Amazon. Appreciate any other tips or suggestions. Thx, Tom

Lots of good info on the glow plugs. On a little diesel like this, ether would be a risky effort. Too easy to overdo it. What some diesel folks do, is put a teaspoon of gasoline on a rag and put the rag in front of the air filter. That gives a more gentle boost than ether. Still, I'd be careful trying even that, on such a little engine. FIRST step is the glow plugs, then anything else, IF needed.

 

[Tom S]

Thx for the input. Yes I've read about ether and the inherent dangers. I'll be putting in the new glow plugs this weekend. Fingers crossed.

 

[dsarow]

Diesels definitely like the heat anyway you can provide it.My question for you is whats the viscosity of your oil.Thick oil will definitely slow the rotation

 

[Tom S]

Diesels definitely like the heat anyway you can provide it.My question for you is whats the viscosity of your oil.Thick oil will definitely slow the rotation

Good thought, I'll need to confirm but I think I used Rotella 15W-40 last time I changed it.

 

[tkhoffman]

Good thought, I'll need to confirm but I think I used Rotella 15W-40 last time I changed it.

That is what i use exclusively in my larger diesel. Athough it is too thick for the temps i see. Especially if you have a weak battery. Diesels need to spin up nicely to start nicely.
In my case, Changing oil for winter seems a waste. 2.5gallons with only 50 hours on it.. i cant justify it. In the garage, block heater and long warm up time before reving it up works for me.