Starter Solenoid, other options

[Greg79]

I need a starter solenoid for a 912ULS and the only place I can find one is Leading Edge Airfoils for $200. Aircraftspruce has several options for $75 to $120. All are 300 amp continuous 12v solenoids. Is there anything special I'm not seeing about the Rotax Solenoid vs Lamar solenoid?

[jrevens]

The are lots of options. A starter solenoid is generally not designed for continuous operation, unlike the master solenoid. Also, one side of the starter solenoid coil is usually connected internally to the case for grounding (-). Power (+) is then sent to the terminal on the solenoid that goes to the other side of the coil for starting. So, the start solenoid usually has only one coil terminal on its body. There are many automotive starter solenoids that could be used also. The designated "starter" solenoids listed in ACS catalog would probably work fine. The ones I see have 2 coil terminals, but you would want to connect one to ground and apply voltage to the other one through your starter switch.

[Geek]

I need a starter solenoid for a 912ULS and the only place I can find one is Leading Edge Airfoils for $200. Aircraftspruce has several options for $75 to $120. All are 300 amp continuous 12v solenoids. Is there anything special I'm not seeing about the Rotax Solenoid vs Lamar solenoid?

John's right - the starter solenoid doesn't need continuous. This one Lamar Starter Solenoid FAA-PMA | Aircraft Spruce (https://www.aircraftspruce.com/pages/el/relays/sts-12s24s.php) is rated at 300A of rush current but not continuous and should work fine. It does have the two connections on the side but hooks up as John described.

Gary

[Eric Page]

If I didn't have a new engine sitting in the crate and I needed a starter solenoid, you'd have a hard time talking me out of using this (http://www.ebay.com/itm/194155003051) -or- this (http://www.ebay.com/itm/124420758059). You might get me to stretch to the automotive version in red (http://www.ebay.com/itm/125093708785) or black (http://www.ebay.com/itm/165282210958). The $85 Lamar is paying for PMA paperwork we don't need.

[Geek]

If I didn't have a new engine sitting in the crate and I needed a starter solenoid, you'd have a hard time talking me out of using this (http://www.ebay.com/itm/194155003051) -or- this (http://www.ebay.com/itm/124420758059). You might get me to stretch to the automotive version in red (http://www.ebay.com/itm/125093708785) or black (http://www.ebay.com/itm/165282210958). The $85 Lamar is paying for PMA paperwork we don't need.

Eric is right in that there really isn't anything really special about the solenoid as long as it takes the surge current. The Lamar is certainly the much more expensive option of either of Eric's options and certain that the automotive variants would work as well. That 100HP Rotax starter probably doesn't pull more current than the starter on a 300+HP car.

Gary

[Greg79]

Thank you everyone for the replies. I think I was overthinking this a bit. I have looked at the suggested options and I also searched for other Denso solenoids available. I came up with the Denso 182800-2280 and was able to find it available in several places. I called Denso and the only info they had was it was intermittent and appeared to be the same as the stock rotax except for the extra blade terminal. Crazy that the manufacturer does not have specs available for their products. The guy I spoke with says this is because they are generally sold to other manufacturers for use wit their components and they would be the ones who have the specs.

Here's link to it

https://www.densoproducts.com/denso-182800-2280-heavy-duty-relay



30307

[Eric Page]

Good detective work. The extra blade terminal is probably for the coil, so you'll have to wire a ground lead for it. The Rotax part is probably made by Denso to Rotax's specs and has an internally grounded coil. Should work good, last long time!