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Honda BA 40 - Won't shut off when warm

T

Tookish

New member
I have a Honda BAFL 40 that runs great. When the engine is cold, it turns on and off great. Once I've been running for 10 minutes or more it no long shuts off when I turn off the key. Pulling the emergency shutoff lanyard doesn't work either. I replaced the ignition switch and wiring harness. All the grounds that I have been able to find look good. Any ideas??
 
Hi,

Looking at a 2003 BA 40 wiring diagram, (it's all I could get off the net) you could try using a jumper wire to ground the black with red stripe (Bl/R) wire at the emergency stop switch when it won't turn off. There's a bullet style connector near the switch that you could use to open the circuit instead of piercing the wire or back probing the switch connector and risk messing something up.

If the engine shuts down then you will know that the fault is likely on the black wire (Bl) side that grounds the CDI ignition terminal and your search along that wire and ground path begins.

If the engine doesn't stop when doing that, you could try grounding the Bl/R wire at the CDI to see if the engine will stop. Again, there is (should be anyway) a connector nearby that you might use but it may be better to CAREFULLY back probe right at the CDI instead.

I say that because, if the engine won't stop grounding the wire right at the CDI, then it is very likely that there is a problem with that internal CDI circuit.

If that's the case, I don't know but I think you could work around that if need be.


If you don't have a wiring diagram or owners manual, you can Google HONDA BF40 OWNERS MANUAL and download one. The diagrams are on the last pages.
Look for one offered from Honda.

Not the greatest clarity but, with a magnifying glass they can be read.

Good luck and let us know what you find.
 
Thank you for that. I will pursue those avenues. Do you think the fact that the engine only has the shutoff problem when it is warm fits into this scenario?
 
Sadly, yes. My first inclination is that the problem is in the CDI. BUT.....if I were famous.....it would probably be because I am WRONG so often.

It could just simply be that the resistance in a wire or a connection increases with the heat of the engine. That's why I suggested those two tests.

Other possibilities might be the ignition coil shorted to power in some way keeping the spark alive or, maybe, auto ignition due to something glowing hot in one or more cylinders.

However, I see both of those as being very unlikely.
 
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