How to wire low pressure switch to stop a Honda GX630 engine

I would like to wire a Honda GX630 engine to stop if the oil pressure sender reads low. It is a 2 magneto engine and runs when it is grounded. I am using a continuos duty solenoid to ground it now. Seems like it should be simple, but I guess I am missing something.

If I understand what you want,cut wire that holds solinoid closed then install pressure switch between cut ends. To keep engine running while pressure builds,try tieing starter circuit to downstream side of pressure switch. If pressure doesn't build high enough while cranking to hold pressure switch closed,install a momentary switch that is held on while starting and shortly longer to alow pressure to build. Hope that answered your question.

Are you planning to use/trying to use existing internal low oil cutoff sw or have you added/plan to add an ext pressure sw.

Joe, I would like to incorporate the low oil pressure sender. If it is easier with a second pressure switch, could go that route. Having a little trouble getting my brain to register.

According to honda website eng has an internal level sensor(probably a magnetic float sw)there is no pressure sw,when oil level normal contacts in sw open(n/o)if oil level low sw contacts close & can be used to light a low oil lamp or kill eng ign.

What you have to do is find wires where they come out of block & connector for same and determine if sw actually being used to light a low oil light or not at all,if sw being used for a light determine if sw being fed with +12v or -12v then splice into wire that goes into light & connect a wire from there to one side of relay coil & connect needed opposite +/- voltage to other terminal of relay coil.

I don't know what style relay you used spdt or dpdt but relay MUST have a set of normally closed contacts(n/c) when at rest(de-energized)connect 1 pole of n/c contact to eng block/chassis,connect kill lead to ign circuit to other side of n/c contact,when oil level in eng low relay will now energize opening contacts & break ground path to ign coils stopping eng.Wheelhorse used a similar system for yrs on their 400/500 series garden tractors with the P series onan eng except theirs would not kill eng ign,float sw would energize a relay & break +12v feed to starter sol coil & light a low oil lite on dash when oil low.

If internal level sw not being used for anything you can connect 1 sw lead to + or - 12v and other lead from sw to relay coil & provide needed opposite voltage to other coil terminal,DON'T use relay in energized position to close ground path to coils,doing so just creates another source of problems as coil may/can burn out due to chargeing voltage(higher)being applied to coil.

Over the weekend a thought occored to me about your orig post,IF you are now useing a sol same/similar to a starter sol & useing ign sw to power coil on same if you install a relay operated by internal level sw DO NOT ground 1 side of n/c contacts in relay,instead break the common ground lead to coils AFTER it leaves sol you are now useing & connect wire THRU n/c contacts of level sw relay to ign coils.

After some thought it occurred to me that grounding one side of n/c contacts in level sw relay wouldn't stop eng when they open due to fact ground path to ign coils still being maintained thru sol/relay you are now useing,line from existing relay to ign coils must be broken thru n/c contacts in level relay to stop eng.