# Preheater start on mf35



## Luke&I (Jul 31, 2021)

Hi!
Turning the key clockwise cranks and cranks the motor for some time til it start eventually starts. Turning anticlockwise should heat up a coil in the intake manifold. I hear some crakle and a puff. Turning further anticlockwise only cranks once and dies. Turning clockwise well it cranks but the preheating doesnt make the engine start any quicker. Also the ammeter doesnt move a hair when heating. 
Anyone had that same issue with their 35?


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## BigT (Sep 15, 2014)

Hello Luke,

You could remove the "thermostart" intake manifold heater and function test it. Make sure the case is well grounded for the test. After 8-10 seconds of pre-heat, it should be emitting fire (burning diesel). Replacements are relatively inexpensive, but make sure your system is supplying diesel to it.









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## SidecarFlip (Mar 25, 2021)

One quick and dirty trick I learned long ago is take a rag soaked in gasoline and lay it over the air cleaner intake and crank it. The gas vapor will pop it right off. Used to do that with my old 6.9 Navistar in my long gone Ford pickup truck. Works every time.


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## Hacke (Feb 22, 2011)

Luke&I said:


> Hi!
> Turning the key clockwise cranks and cranks the motor for some time til it start eventually starts. Turning anticlockwise should heat up a coil in the intake manifold. I hear some crakle and a puff. Turning further anticlockwise only cranks once and dies. Turning clockwise well it cranks but the preheating doesnt make the engine start any quicker. Also the ammeter doesnt move a hair when heating.
> Anyone had that same issue with their 35?


*NO!!!*
Please, do not follow the gas rag advice! 
Apart from harming yourself, you can destroy parts of the tractor.
No starting fluid. Use nothing but the Thermostart flame heater. 

The engine cranks when the key is in normal starting position.
The starter circuit is OK.

The Thermostart seems to work when the key is in preheating position.
To be sure of the Thermostart function, remove the hose from the intake manifold and look inside when the key is in preheating position.
If the Thermostart works as in the video below (apart from the heat+crank part), its circuit is OK.
Turn down the volume first, there is a loud intro sound.

If both tests above are successful, the problem with heating and cranking could be from:

*Bad battery/ies.*
Not very likely, but check to be sure.
Check the battery voltage at rest.
Check the battery voltage when you crank.
Check the battery voltage when you heat+crank.

*Bad battery connections or/and wiring.*
Check the wires between the batteries (if 2x6 Volt), and from battery to ground and battery to starter. 
Check the connections for these wires.
Pay close attention to the ground connection.

*Bad ammeter.*
Bypass the ammeter and try the functions.

*Bad key switch.*
Remove the wire that goes to the Thermostart, at the key switch.
Connect that wire end to the battery (-) post, the Thermostart should go on.
After 10 seconds of heating, keep the Thermostart connected and crank the engine with the key in normal cranking position.
If both heating and cranking can be simultaneously done this way, the key switch is bad.


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## SidecarFlip (Mar 25, 2021)

Hacke said:


> *NO!!!*
> Please, do not follow the gas rag advice!


Interesting comment. I must ask, have you ever tried it? Somehow I don't believe you have but please tell us... I'm not saying it's recommended but it's a do at your own risk thing and it's certainly better that either


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## Hacke (Feb 22, 2011)

SidecarFlip said:


> Interesting comment. I must ask, have you ever tried it? Somehow I don't believe you have but please tell us... I'm not saying it's recommended but it's a do at your own risk thing and it's certainly better that either


No, I have never used a gas rag on a tractor equipped with a flame heater.


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## Luke&I (Jul 31, 2021)

Testet the heater with a clamp meter and it draws 14 amps and the manifold feels quite hot after around 20sek and I hear chuckle from somewhere around front of the tank and puffs where the heater is. Removed a plug next to it and smoke and fire spewed out.
The battery is 12.7v unloaded and 12.4 and dropping when cranking.
I found a date on the battery. But am not sure what year. Its a varta blue dynamic CAC9580921072
95Ah 830A(en)


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## SidecarFlip (Mar 25, 2021)

Lets rephrase it then.. Have you ever used a gas soaked rag to start ANY diesel? Only thing you have to worry about is the rag getting sucked in the air intake... All that transpires is the motor gets a 'whiff' of gas vapor which isn't as volatile as either, but is more volatile than ice cold diesel fuel is,, so the chance of internal mechanical damage is a lot less.


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## SidecarFlip (Mar 25, 2021)

Luke&I said:


> Testet the heater with a clamp meter and it draws 14 amps and the manifold feels quite hot after around 20sek and I hear chuckle from somewhere around front of the tank and puffs where the heater is. Removed a plug next to it and smoke and fire spewed out.
> The battery is 12.7v unloaded and 12.4 and dropping when cranking.
> I found a date on the battery. But am not sure what year. Its a varta blue dynamic CAC9580921072
> 95Ah 830A(en)


When unsure of the build date on any flooded cell battery, the easiest thing to do is replace it. Surface charge means little it's all about cranking amps and duration of amps delivered. In my view, ALL batteries are a consumable, consequently they get replaced regularly and not knowing the age of it makes me highly suspect of it being old and tired.

Instead of buying an identical battery, buy the largest one with the most cold cranking amps, that will fit in the battery tray. The larger the better. What I do on all my units. Better to have excess capacity than marginal capacity and you charging system don't care, it will charge any sized battery.


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## Hacke (Feb 22, 2011)

Luke&I said:


> Testet the heater with a clamp meter and it draws 14 amps and the manifold feels quite hot after around 20sek and I hear chuckle from somewhere around front of the tank and puffs where the heater is. Removed a plug next to it and smoke and fire spewed out.
> The battery is 12.7v unloaded and 12.4 and dropping when cranking.
> I found a date on the battery. But am not sure what year. Its a varta blue dynamic CAC9580921072
> 95Ah 830A(en)


14 A for the Thermostart is OK.
12.7 V unloaded, battery is fine.

12.4 V during cranking is way too high.
Check the wiring as suggested.
Measure the resistance in the wire between battery and starter.
Measure the resistance in the wire between battery and ground.
Measure the voltage between ground and starter at rest.
Measure the voltage between ground and starter during cranking.


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## Luke&I (Jul 31, 2021)

Checked the starter switch and it is weird. There is some intermittant continuety all over. I think the heater is turned on when cranking also. Not sure. Anyway, put a charger on the battery and it took some juice. Now it also cranks in the heater/start position. Just weird it couldnt before. Could it be because the heater also Is drawing current? Let it heat for 20sek and and it started on the second turn. 
Also found an almost broken off wire to the selonoid.


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## Hacke (Feb 22, 2011)

Start by checking the wiring, like I suggested. Did you do that?
Next step is the rest of the wiring. It is just a few wires, so renew them.

When you know that the wiring is OK, you can start looking at other components. You need to eliminate part by part of the system in order to find the culprit(s). If you are poking around a little here and a little there, you are not getting anywhere and it is impossible to give proper help.


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## Luke&I (Jul 31, 2021)

The resistance is zero and the rest voltage was also zero.


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## Hacke (Feb 22, 2011)

You measure the voltage between the battery post on starter and ground.

Put shut off knob in off position, so the engine do not start when you crank.

First you measure at rest.
Then you measure during normal cranking.
Wait 5 minutes for battery recover.
Preheat for 10-15 seconds (a flame burning for 5 seconds).
Immediately after that, measure during heat+crank.


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## Luke&I (Jul 31, 2021)

At rest: 0 volt

Normal cranking: 10.3v

Crank+heater: 10.3v


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## Hacke (Feb 22, 2011)

I think you use the wrong stud.


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## Luke&I (Jul 31, 2021)

It is 12.6v


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## Hacke (Feb 22, 2011)

It seems like there is nothing wrong with the battery or its connections.
Starter/solenoid/relay is working.

We have:
Starter start, but stops when key switch is in heat+crank position.
Heat+crank is sometimes engaged, even with the key in only crank position.
Ammeter does not react when heating.

Check the connections at the backside of the key switch. Make sure that everything is clean and that the wires and connectors are OK. Follow all wires to their destination, if you have the slightest doubt about condition, renew the wire. I would renew all the wires, there are not many of them and you will be certain that they are OK. A wire may look fine, but there can be problems inside.

If you still have problems, bypass the ammeter.
Still problems after that, get a new key switch.


The ammeter problem can of course be due to a bad key switch, but when the Thermostart is working, the ammeter should react.
Previous owner may have been rearranging the connectors at the backside of the ammeter.
Check the wiring at the ammeter and confirm what wire goes where.


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## Luke&I (Jul 31, 2021)

The anmeter isnt working when cranking either. Only when light is on and when motor is running. When running it is slightly past the zero on the plus side.
Cant find any loose other than that coming from the horn. Dont know what that empty spade connector on the solenoid is for.


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