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Honda 150 hp BAPJ crank/no crank

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Pohnpei Surf Club

Member
Hello Guys.
I have a Honda 150 BAPJ from 2019 or 20.
When the motor is running hot, and I turn the motor off, and I try to start it again, It won't crank, but there is power coming to the key switch.
The lights come on and it does the double beep.
If I give it 15 minutes, for the motor to cool down a bit, it cracks right away, no problem.
So it seems the problem occurs when the motor is hot.
After this problem started, I have installed a brand new starter and key switch panel, and the problem persists, so it is not the starter, or the key switch panel.
I also changed the cubic relay on the fuse box.
Could it be a different replay, or I was also too the solenoid that feeds power to the solenoid on the starter.
Thanks. Allois
 
Hi Allois,

My first suspect for this would be poor battery cable connection or defective battery cable. It could be on the positive side or the negative as both are equally important in the circuit.

Here's why I say that:
Heat in a circuit creates increased resistance. A connection or a cable that is marginally doing it's job of allowing current to flow, may become more resistant when heated up.

A troubleshooting technique called voltage drop testing would help you easily identify where the problem is occuring in the circuit precisely, without guessing or trying new parts.

It's not hard to learn but will take some reading and a decent multimeter to try.
Lots of great tutorials and videos about it on the web.

It's important that you understand that when volt drop testing, the circuit be in use. Meaning, for example, that, you connect your meter leads where you want them and then you try starting the engine.

Another thing that's hard to grasp, at first, while you are using a voltmeter, it's not necessary to to connect the positive lead to positive or the negative lead to negative because you aren't checking for supply voltage. What you instead want to measure is how much voltage is being consumed by a given connection, cable, wire, or component in the circuit..So, you can actually connect one lead to the battery post and the other to the battery cable clamp...hit "start"...and read directly on the meter how much voltage is "dropped" between the post and the clamp.

Or, you can connect one lead to the battery cable clamp and the other to the battery cable end connected to the starter...hit "start" and read directly on the meter how much voltage is lost (dropped) in that cable. It's almost a "magical" way to observe how well that cable is "working" or if it's bad.

Hope your eyes aren't rolling around reading this but it's well worth the time to learn how to do this.
..
 
A wire cable that is rusted inside its plastic case will do this, caused by an invisible hole in the plastic. The voltage drop rest should find it
 
Two questions first. When it will not crank hot, is the starter dead silent, or do you get a clunk from the solenoid? And have you tried turning it over by hand with a socket on the crank bolt right after it quits hot?

Here is why I ask. Silent means the control side never told the solenoid to pull in. A clunk means it did, and the fault is downstream in the solenoid contacts, the cables, or the ground. Two completely different hunts. One meter and five minutes separates them.

Next time it does it, do not touch anything else. Meter on the small trigger wire at the starter solenoid, other lead on a good ground. Hit start. Battery voltage there and nothing happens, the trigger side is fine and you are chasing the solenoid or the big cables. Nothing there, walk backwards through the relay, the neutral switch, and the harness. Beats swapping another part.

The ground is the one everybody skips. The cable from the block back to battery negative runs right against a hot powerhead. I chased the same thing on an old rig for a month once. Ring terminal was green under the shrink tube. Looked perfect from the outside...

I would not put the neutral switch or the lanyard high on the list. Those do not care about temperature. Yours clearly does.

I could be wrong on this next part. I have never seen the overheat protection on one of these kill the crank circuit, it usually just sets the alarm and derates rpm. Somebody with more Honda wiring time than me may say different.

And do the hand turning test. A motor that drags when hot will act the same way, and a new starter will not fix mechanical.

What is the full model and serial off the bracket, anyway? BAPJ covers more than one year and the harness is not always the same between them.

Keep us posted on what you find. Thanks.
 
Something "quick and dirty" you can try to find if its a bad batt cable is to overlay a jumper cable from battery to starter. I do that on cars but it's not as easy on outboards.
Just another trick/idea if you wanted to give it a try.
You need to be really careful to prevent "accidental welding" and shorting out.

Good luck.
 
jgmo said:
Something "quick and dirty" you can try to find if its a bad batt cable is to overlay a jumper cable from battery to starter. I do that on cars but it's not as easy on outboards.
Just another trick/idea if you wanted to give it a try.
You need to be really careful to prevent "accidental welding" and shorting out.

Good luck.
Click to expand...
Thanks!!
I will be looking at all the options and will get back to you.
Thanks. Allois
 
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