95 Spx shuts off after 30 seconds

[bubone]

I have a 95 spx that I am rebuilding , just finished motor and carbs. It starts great and runs exactly 30 seconds then shuts off. I did a timer test and the 30 seconds is consistent. I also noticed that if I hit the start button quickly around 25-29 seconds it will run for another 30 seconds?? Any ideas? I’m running hooked up to a hose ?

 

[sretooh]

Sounds like a wiring / electrical issue. Did you check all fuses? Look for unattached wires or broken wires?

 

[glsmohio]

this is very interesting. 1st remember even though you have water going to the engine you dont have anything going to the pump or your carbon seal. does your beeper work? they will give off codes.

 

[jts32]

33 sec is how long the mpem will power up with the key off and hitting start button. Almost like it's not recognizing the key is on the post, but don't understand why it would initially start then. See what it does without the key on and hit start button. When it's running, does pulling key off kill the motor?

 

[bubone]

Ok, It turns out the problem was the MPEM, the module turns off power after 30 sec when then engine stops, this is normal. The MPEM must have an internal failure causing the engine to turn off.
Anyhow, replaced the MPEM and all is fine now.