Key Switch Works Sometimes

[Travis242]

Hello all!
New here need help. I bought a 90hp 2stroke (i may have been jipped thinking it's a 85hp but no biggie). I stripped it down bare and changed everything (only kept the power head) it was in bad condition. But I'm getting it back together now and it runs. My problem is my key switch doesn't work sometimes. When this happens, If I use a rope around the flywheel and start the motor it runs and shuts off from key or kill switch....then it may start from key........

Now a history on how I think the problem started.....

Thing is I had trim n tilt problems from switch. It would only trim down was getting a 'click' when i tryto trim up....after replacing relay (brand new) i had the same problem. Baffled I opened my control box (also brand new) I realized one of the screws that holds the box together went straight through the blue (trim up) wire ♂️......I repaired the wire but now when I try to trim I get a 'click' and key switch goes out.
It feel weird even trying to explain. But can it be the trim switch is bad or has a short? Or did the screw through the trim wire cause the key switch to have a short? Any help or point in the right direction is GREATLY APPRECIATED! I am at a dead end on what to try next before I go buying more parts. I need to know what to buy♂️

[99yam40]

low battery or a bad connection (pos or neg) could cause this type of problem

[Travis242]

low battery or a bad connection (pos or neg) could cause this type of problem

Thank you for replying. Battery tested fine this morning so next step is connections I guess. Willing to try anything at this point

[99yam40]

how did you test the battery?
load test?

does the key switch energize the start relay/
do you hear a click when turning key to start?
or was that just the trim switch that just clicked?
testing voltages to and out of the key switch will tell if the switch works or not

[boscoe99]

If the key switch works some times and does not work some times, why has the key switch not been replaced?

Presumption being that you have done trouble shooting on the key switch and found that at times it is good and at times it is bad.

[Travis242]

how did you test the battery?
load test?

does the key switch energize the start relay/
do you hear a click when turning key to start?
or was that just the trim switch that just clicked?
testing voltages to and out of the key switch will tell if the switch works or not

Did a test with millimeter on battery voltage was 11.1 standing and with engine running it went up to 13. So I figured that was fine. :/

No click when turning key to start just when I try trim switch.....it clicks once then nothing from key or trim switch ("dn" only'). When the key switch actually does work to start the engine is the only time I get the click from trim switch....but once I try it and it clicks I get nothing. This is sooooo strange and has me baffled and frustrated.

I tried something today... while the engine was running, the key bumps the starter just fine with no hiccups (I know im grinding the teeth but i had to try it and it works while its running). How can I test the voltages in and out of the key switch (which wires)?

[Travis242]

If the key switch works some times and does not work some times, why has the key switch not been replaced?

Presumption being that you have done trouble shooting on the key switch and found that at times it is good and at times it is bad.

The only reason being is that it is a brand new control box and harness and I hate to believe my money went down the drain Lol

Just want to be sure that it is bad before buying a new one

[fairdeal]

How can I test the voltages in and out of the key switch (which wires)?

the red wire brings 12v+ from the motor
when the keyswitch is 'on', it connects that power to yellow

'start' connects it to brown, which has to pass through the neutral switch
to get back to the motor

the trim switch connects it to blue or green

[99yam40]

Did a test with millimeter on battery voltage was 11.1 standing and with engine running it went up to 13. So I figured that was fine. :/

No click when turning key to start just when I try trim switch.....it clicks once then nothing from key or trim switch ("dn" only'). When the key switch actually does work to start the engine is the only time I get the click from trim switch....but once I try it and it clicks I get nothing. This is sooooo strange and has me baffled and frustrated.

I tried something today... while the engine was running, the key bumps the starter just fine with no hiccups (I know im grinding the teeth but i had to try it and it works while its running). How can I test the voltages in and out of the key switch (which wires)?

you have a bad battery or needs to be charged
it should be 12.7 v or better when the motor is not running/ charging it.
and I would expect it to be even higher while motor is running and charging it if everything is in good shape

[robert graham]

I've had old ,weak, tired, warn out batteries make a monkey out of me, even if testing showed "good"....how old is your battery?....maybe replace that battery with a fresh new one and most of your problems may disappear...

[Travis242]

Thank you all soooo much for your help. Did everything you all said....everything tested out just fine. Fully charged and load tested the battery, checked voltage to and from key switch, and trim switch, checked all connections.....everything was just as it should be. Decided to start rewiring the engine and I'm ashamed to say but i found a ground wire not screwed down tightly to the engine (the main harness ground wire) it was cross-threaded so it could not torque down. Changed it and everything works 100% now. I feel soooooo foolish now lol but i knew it had to be something simple. Had it now been for you all helping I probably would not have found it. So thank you again, definitely will be back with more questions lol. This is my first boat so I'm new to it all but learning so much. Thank you thank you thank you!

[99yam40]

Thank you all soooo much for your help. P


Pp

might try a known good battery to start out with.
or charge up the battery you have and then have it load tested to make sure it is a bad one