Since I got my M/F 1529, last fall, it has always seemed to cold start kind of dirty to me. I recently pulled the glow plugs and checked them for visual performance. They did have some carbon deposits, which led me to believe, that they weren't getting hot enough in 15 seconds. They all measured about the same resistance and all glowed. In the initial test, the center G/P didn't appear to me, to be quite as strong. After about 15 seconds. FYI: These NGK G/Ps are $70.00 ea. from a dealer, but can be gotten for less that $15.00 ea. on the Internet
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I got 3 new G/Ps and did the same test.
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I believe, the new G/Ps allow cleaner cold starting, but it's been a little warmer, so haven't really come to a final conclusion.
Do you have a wiring diagram for your tractor. If so could you please post it.
There have been many cases where the circuit wiring for glow plugs has been wrong for years. Wired in parallel when they were designed to be wired in series is one example.
This marked up wiring diagram is for different machines than yours but I provide it to illustrate the difference in GP wiring and how easy it is for someone to do it wrong and then, ever after, the next owners just copy what the first wrong did.
Below is a caution from the NGK Horticultural, Agricultural and Industrial Catalogue.
Testing Sheathed Type Glow Plugs
In order to check the heating coil, measure its
resistance as shown in the diagram (excluding
double insulated, YD, CX type part numbers). Some
resistance values are extremely low (such as some
QGS types) and should only be tested with an
Ohmmeter capable of recording values down to
0.1Ω. Testing glow plugs by connecting directly
across a battery is NOT recommended as, apart
from risk to personal injury, damage can occur to
the internal construction of the glow plug if it is not
designed to have continuous voltage applied (e.g.
QGS types).
Resistance value ∞: The heating coil is broken
Resistance value less than 5 Ω : The heating coil is in
good condition
Dave M7040