Starter solenoid heat shield for ZD21.

[Fitch]

I was having problems with the mower (2004 ZD21 with ~1,300 hours at the time) not starting when it was hot. The solenoid would click but it wouldn't engage. No problems cold.

I used an IR temperature meter and discovered the solenoid was being heated to nearly 450F by the exhaust manifold.

After some investigation I learned the new ZD1021 had a heat shield over the starter solenoid. It looked like it could be made to fit, so I ordered one.

Bottom line, I was able to make it fit and it radically lowered the operating temperature of the starter solenoid. After installation I measured the following temperatures:

Manifold: 648 - 689F

The manifold is hottest between the first two ports farthest from the from the muffler. The muffler itself was in the 350 - 400F range.

Shield: 456 - 468F
Solenoid: 119 - 126F Yup, surprised me too. I measured it several times.
Starter: 119 - 122F

The mower now has 1,602 hours on it and the hot start problem has not happened since the shield installation. At this point I'm concluding the hot start problems are cured.

The installation required drilling two holes. I relocated the muffler support brace bottom bolt to hold the shield in place and drilled a second hole for the second shield mounting bolt. The pictures shows that more clearly than I can explain.

Fitch

 

[rentthis]

I have to agree. Those temps sound nuts. When I get home, I plan to look at how my ZD323 is set up. Does your machine have signs of having had a guard previously? It's amazing that the starter lasted 13 years.

 

[fatjay]

Interesting. Sometimes I have to hit hte button a couple times before it engages the starter, hot or not. Maybe it already got cooked. I've been looking at a new starter solenoid, if it just happens again it'll be pointless, so it's probably a good idea that I get a shield.

 

[Dave Rees]

I was having problems with the mower (2004 ZD21 with ~1,300 hours at the time) not starting when it was hot. The solenoid would click but it wouldn't engage. No problems cold.

I used an IR temperature meter and discovered the solenoid was being heated to nearly 450F by the exhaust manifold.

After some investigation I learned the new ZD1021 had a heat shield over the starter solenoid. It looked like it could be made to fit, so I ordered one.

Bottom line, I was able to make it fit and it radically lowered the operating temperature of the starter solenoid. After installation I measured the following temperatures:

Manifold: 648 - 689F

The manifold is hottest between the first two ports farthest from the from the muffler. The muffler itself was in the 350 - 400F range.

Shield: 456 - 468F
Solenoid: 119 - 126F Yup, surprised me too. I measured it several times.
Starter: 119 - 122F

The mower now has 1,602 hours on it and the hot start problem has not happened since the shield installation. At this point I'm concluding the hot start problems are cured.

The installation required drilling two holes. I relocated the muffler support brace bottom bolt to hold the shield in place and drilled a second hole for the second shield mounting bolt. The pictures shows that more clearly than I can explain.

Fitch

I am having the same heat problem with my ZD21 mower. How can I order the heat shield # 456-468F?