Engaging thermostart - starter will not turn over

TennFire

Member
I am trying to figure out a symptom on a MF250 which has a Perkins 3cyl diesel when trying to start in cold weather. At temperatures below 35 or so, it does not want to start when cranked without the thermostart.

This summer, I replaced the thermostart and also the switch. the switch has 4 positions - off, run, a spring loaded heater position and crank.

If I apply the key to the springloaded tension (which I understood was how the thermostart works) for 30 seconds to a minute, I normally have no response if I then move the key to the crank position. Nothing, not even a click. If I let the tractor sit for a few minutes, it seems it will crank but I normally end up with ether to start it at this point.

Anyone had this problem or ideas on how to run down this problem.
 
I wonder if you have the right switch, and wired correctly? The first spring loaded crank to the right is start, the first spring load to the left is heat, and further left is heat-start together. there is no "on" position with the correct switch.
 
Hmmmmm. On my MF-240-S, there's four positions; Going left to right, there's Stop, then there's Run, then there's Thermostart-Heat, then there's Crank-The-Starter. I go right and hold at the Thermostart-Heat position, for 30 seconds, or 60 seconds, then go one more position right to Crank-The Starter, then release it, get her running and set her at 1200 rpm to warm up. Doesn't always fire up, have to hold my mouth just right, but always cranks.
 
Dieseltech, I don't think its the wrong switch, but I could be wrong. I ordered the switch online from one of the dealers that handles a lot of MF parts. It looked identical to what came out, although I concede that the one in the tractor could have been the wrong one. My current switch seems to work just likeFBH44 describes.

Now, its possible that the prior owner or someone has previously have miswired it. I guess I do need to consider that option since I put the wires back just like they were.

Anyone with a MF250 (or similar) that can tell me which color wires go to which tabs on the switch or other ideas?
 
Hi,
UK-made 230s never had the original left and right turn key switch. UK 230s have a 4-position switch. When turned fully anticlockwise it is in the 'off' position. One step to the right gives you 'ignition' which energises the warning lights etc. The next step to the right is the 'heat' position and finally the last step is to 'start'. Make sure using a voltmeter or a test lamp that you are sending current to the thermostart. On top of the gearbox you will see a rubber boot. This is the starter safety switch so that you cannot start the engine with the tractor in gear. For the purposes of the test ONLY, pull the connectors and join them together clear of any chassis part. These switches do fail and that might be the problem.
So, check that the switch is wired correctly to start.
Let us know what you find.
DavidP, South Wales
 

DavidP, first, thanks for all your posts and comments on some many topics on this site.

Now, today I used a test light and probed the switch and wiring. The switch has the 4 positions asyou indicate. With the test light, the thermostart tab lights in the 3rd, spring loaded, setting but not the starter (which is as it should be it appears). Starter powers in the 4th setting only. Still, if the thermostart is engaged for 30+ seconds, the starter makes no sound unless the key is turned off and left off for about 2-3 minutes.

I checked battery status also and made sure to put it on the charger until it showed 100% and entered maintenance mode. It does not appear to be a battery issue. Also disconnected all connections (even on starter and the solenoid - which were a chore to reach with the loader on the tractor) and cleaned each connection.
 

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