Troubleshooting electric start - 15 HP Johnson 1988.

[The Famous Grouse]

Bought a 15 HP Johnson that hasn't been running in about a decade. It's a 1988 model, electric start and came from the factory with e-start.

In the test tank on Saturday, I hooked it up to a starting battery. This battery was from my fishing boat and I know it is charged and working. Just to make sure, I put it on the charger and it's topped up. Bottom line, battery not the issue.

Nothing happens when I hit the start switch on the 15 HP. No sound, nothing. It doesn't click, humm, buzz or anything.

I manually moved the starting gear up into the flywheel and pulled the rope just to see if the starter motor was frozen and it is not. It appears to spin freely.

Could someone give me a few pointers on troubleshooting? What to check first, second, etc.

Is there, by any chance, a fuse that could be blown? I looked and I don't seen an obvious fuse holder, but it might not be that obvious.

All help appreciated.

Grouse

 

[the machinist]

Re: Troubleshooting electric start - 15 HP Johnson 1988.

There is no fuse on that motor. But very likely a wire to or from the switch button may be corroded or broken. That motor uses the block as a conductor for the ground, so you have a bad connection or corrosion from the starter motor to the block (which is your ground) or the ground wire from the battery (usually connected to the front motor mount under the carb) may not be good.

One thing on that motor, on the electric starter motor, IF you unscrew the one wire going into the lug on the housing be CAREFUL that the threaded lug itself does not rotate as the nut comes loose or you WILL twist the wire off inside that goes to the windings. There is very little room inside and very hard to repair if at all. Or the brushes inside are worn or seized up & not making good connection to the communtor of the armature.

 

[The Famous Grouse]

Re: Troubleshooting electric start - 15 HP Johnson 1988.

Thanks for the reply, Machinist. Looks like taking the switch off and inspecting contacts would be a good place to start. Hopfully I can trace/verify the wires running from the switch to the starter to make sure there isn't a broken wire.

I saw the battery ground by the carb and inspected that to make sure there was no corrosion under that connector.

Is there any way to verify that the starter is making good contact with the block such that it is grounding to the block properly? Given your warning above, I'd rather not take the starter motor off unless I have to.

Other ideas?

Thanks.

Grouse

 

[64osby]

Re: Troubleshooting electric start - 15 HP Johnson 1988.

Use an ohm meter and test for continuity with the battery disconnected.

Jump your starter with your battery and some cables to see if it's working, bypass your switch.

 

[The Famous Grouse]

Re: Troubleshooting electric start - 15 HP Johnson 1988.

Good tip. Much appreciated.

I've come a long way with this motor. It was hard just to get it to even fire, but I did get her to run, but only at high idle. I'm sure the carb is all gummed up. The typical situation, improper storage and lack of use being far worse than being used too much.

I figured as long as I'm going through this thing, I'm going to get everything to work properly. No sense doing it half way.

I need to get it out on the stand in my garage and get all my work lights set up. Gets dark early now and work time is limited to after the kids go to bed.

Thanks for the tips and always happy to hear more ideas.

Grouse

 

[gozierdt]

Re: Troubleshooting electric start - 15 HP Johnson 1988.

If you're going to be doing more work on this engine, be sure to go to "the machinist" site
"LeeRoy's Ramblings". There's a ton of information on these engines. He doesn't toot his own
horn much.

http://www.leeroysramblings.com/#12_OB

articles 31-40 are all about these engines...

 

[The Famous Grouse]

Re: Troubleshooting electric start - 15 HP Johnson 1988.

Wow. That is a treasure trove. Thanks for the link, lots of good stuff there.

Grouse

 

[Throbbin Rods]

Re: Troubleshooting electric start - 15 HP Johnson 1988.

I have had several of those electric start switches cast their withers - be sure to check the switch with a ohm-meter.