engine swapped now starts won't die

[rphillips]

Embarrassing with so little info, but, Shade tree mechanic swapped motors for my bro. Older (?) 40 merc. for newer (?) 40 merc. Didn't swap controls & wires, just cut wires. Old harness from controls had 6 wires, newer eng. had 9 or 10 wires coming out of harness from eng. We've finally figured out Trim, all working as should. Found elect. choke & it clicks when we push the choke button so seems to be working. Got starter working as should with ign. key & eng started fine, but when turn ign. key off eng. keeps running, pull kill switch it keeps running, pulled batt. cable & it keeps running. Put hand over carb inlet to kill eng. Any clue what needs hooking up to kill eng. We're lost.

 

[Scott Danforth]

Get the wiring schematic for both motors

 

[Chris1956]

The harnesses are likely compatible, unless the older motor was from the 60's. It sounds like your ign killer wire is not connected correctly. On older controls (~pre-1978) it would be salmon or orange. On newer controls it would be black/yellow. On the motor is it likely black/yellow.

Since you disconnected the battery with the engine running, you likely fried your rectifier or voltage regulator.

Years of both motors would really help my guessing.

 

[rphillips]

Chris... sorry for the lack of info, We have no idea of how old either eng. is. Thanks for the tip on wire color, at least a point toward the right direction, we were lost... Never thought of frying anything by unhooking the batt. We just got excited as eng wouldn't stop, & just went to trying what was there. If we'd took time to think, covering the carb worked great, it just wasn't the first thing we thought of...Thanks, we'll see what happens.

 

[merc850]

Post the serial Nr. of the new motor.

 

[rphillips]

Not sure of SN, there's one # on the ID plate but a different # on top of the fly wheel where the SN is located on my 150 Merc., not sure which is SN. We hooked the orange wire form controls to Black & yellow wire from eng. as Chris said, worked like a charm, starts & dies just as it should... Never thought it would be that simple but sure glad it was. Sure do appreciate the help. Next we couldn't find a pee hole. Looked all the way around, nothing, looked inside the cowl for a little hose coming from eng. block or head to side or back of cowl but no hose anywhere. Did some digging around this site & think I found the "97" 40 hp Merc has no pee hole. Surely this ain't right, it makes no sense. There was a thing telling how to make & install one. Is there a way to tell if it's circulating water without waiting to see if overheats? it has no horn or beeper or anything that we know of. Any help really appreciated.