1986 Mariner 150 no fire to spark plugs.....sometimes

[ruggerlock4]

Took boat out a few weeks ago and it start right up at launch. Ran great, WOT at 55mph, to fishing spot. After sitting for about 30 mins, I went to start it and it fired right up, put it in gear and it died. Tried starting again and it would just turn over. I tried for a few mins and thought maybe I had flooded trying to start. I let it sit for about 15 mins, and tried it again. After a few tries it fired up and I went on to next spot. After fishing for about an hour, I tried to start it and nothing. After sitting for another 15 mins, I tried again, but this time nothing, just turns over. I ended up having to troll back to launch, about 90mins. I tried it maybe 3-4 times on the way back, and nothing. Once I got home I checked to spark plugs, and I wasn't getting any fire to them. I checked the switch boxes, but I find it hard to believe that both boxes would have gone out at the same time. I went back out there this weekend to mess with again and while it was turning over it hit one time and that was it. Tried a few more times and it would hit at random times. It seems like Im getting fire every now and then, pretty lost at this point. Any suggestions on what the problem might be?

 

[achris]

Re: 1986 Mariner 150 no fire to spark plugs.....sometimes

Check the grounds to the switchboxes... Also check the kill wire and the tilt kill switch...

Do you have an engine serial number we can work with?

Chris......

 

[ruggerlock4]

Re: 1986 Mariner 150 no fire to spark plugs.....sometimes

Sn: A183703

 

[snowbrd84]

Re: 1986 Mariner 150 no fire to spark plugs.....sometimes

x2 on checking the grounds. Also, what is the general condition of the wiring on the motor? If there are a lot of corroded connections and brittle wires, something could be intermittently losing contact. You could go one by one disconnecting, cleaning, and reconnecting each connection on the switch boxes and other components. I use a Dremel with a tiny wire wheel for doing this. Good luck.

 

[James R]

Re: 1986 Mariner 150 no fire to spark plugs.....sometimes

Try disconnecting the yellow wires at the rectifier. It is a common fault when the rectifier goes out. If the motor runs without the rectifier replace the rectifier.

 

[ruggerlock4]

Re: 1986 Mariner 150 no fire to spark plugs.....sometimes

Try disconnecting the yellow wires at the rectifier. It is a common fault when the rectifier goes out. If the motor runs without the rectifier replace the rectifier.

I removed the yellow wire and still nothing. Should it still start with the yellow wires removed?

 

[James R]

Re: 1986 Mariner 150 no fire to spark plugs.....sometimes

The yellow wires are only for the charging system and disconnecting does not affect the running.
That was the last quick test before doing resistance checks on the stator and trigger. This will be necessary to eliminate those before deciding on powerpack replacement. A manual on your motor is a blessing.