Testing Thermostart

David G · Feb 13, 2016

I have had my tractor 12 years and never used thermostart, so tried it today.

I held it between on and crank for about 20 seconds, it was in heated shop, but seemed to pop off cleaner.

How do I verify it?

JoeM(GA) · Feb 13, 2016

David on most Fords you can remove the rubber air inlet tube at the manifold, look into the end of the manifold and have someone activate the thermostart.
You should see it start to heat up and glow. When it's hot enough the valve in it will allow fuel to drip on the element and catch fire. When the key is rotated to start, the fire would be sucked into the cylinders to help start it. Not sure on all Fords, but on my 345C it takes about 30-45 seconds before fuel begins
to flow.

Dieseltech · Feb 13, 2016

If it is REALLY quiet you can hear the flame start at about 12-15 seconds, then start cranking the engine to draw in the heated air. CAV/Lucas/Delphi has several thermostarts available for natural or turbo engines, and in three size fuel flow ratings. The service letter states to never use for more than one minute, and never use without making sure the fuel line is bled of air or the coils will be damaged. The MF 35 and 85 diesels I have both use them, and you can hear them both if surroundings are noise free. If held on about 45 seconds you can feel the intake will be warm after the engine starts too.

JF in MI · Feb 14, 2016

OK, so here is my question; Are you supposed to wait until AFTER you hear the 'pop' or just before? I always thought the idea wad heated fuel or is it better for it to have burned up?

Rustytractorguy · Feb 14, 2016

When I tested mine, we had the rubber hose removed and eventually there was some smoke come out of the intake.

Bern · Feb 14, 2016

Pull off intake hose and hold key switch to "heat". If smoke and/or flames come out, it's working.

Fordfarmer · Feb 14, 2016

After. Ideally, you get it cranking quick enough to suck the flame into the cylinders. Even if the flame is already out when you start cranking, the resulting heat is much more than you'd get from just the heating element.

Testing Thermostart

David G

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JoeM(GA)

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Dieseltech

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JF in MI

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Rustytractorguy

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Bern

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Fordfarmer

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