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ContinuousWave: Small Boat Electrical
Engine cranks with ignition off
|Author||Topic: Engine cranks with ignition off|
posted 03-05-2008 11:43 AM ET (US)
1963 Whaler, 1995 Evinrude 48SPL.
It has been sitting for a year. We had a new baby, and well, you know what happens with weekend boating under those circumstances. I am trying to get the boat running again, and among other things, I am having this problem:
The engine cranks even with the ignition switched off and the key pulled. Even disconnecting the ignition switch wiring does not prevent this.
The battery is about 2 years old, and I had it partially charged (it was completely dead) with a battery charger (10 amp charger). Leaving the charger attached for a bit more power, I cranked the engine a few times, and although the engine didn't catch, turning the switch back off stopped the engine from cranking. Well, after trying to start the motor a few times, it gets stuck on cranking, even after pulling the key. This happened on Sunday. I worked on it again yesterday, and same thing --cranks fine a few cycles and shuts off when the key is turned back to the off position but then stays cranking. It cranks weakly a bit and then the internal breaker on the charger snaps off. After about a minute, the charger snaps on again and the engine starts cranking-even with the ignition switch completely removed.
posted 03-05-2008 12:21 PM ET (US)
Sounds like a stuck solenoid. I had a similar problem with my 1986 Mercury 150 a few years ago before I repowered.
Take the cowling off and gently tap the starter motor solenoid with a hammer. The solenoid is sticking open in the "crank" setting.
As you know, a solenoid is electro-mechanical. The hammer will help disengage the soleniod.
If this works, simply replace the solenoid (about $20 for the part and about 10 minutes for the labor). It has two wires and will be attached to the powerhead, likely near the starter motor (Check your service manual).
posted 03-05-2008 01:38 PM ET (US)
"Sounds like a stuck solenoid."
Thanks, just picked one up at the local BoatUS during lunch hour here. I had a feeling it could be the low/high voltage switch last night, but looking at the Seloc manual didn't turn anything up in the index. For some reason my brain was stuck on the word "relay".
Cheers and thanks,
posted 03-05-2008 03:49 PM ET (US)
Could also be the starter, had this happen on a car I had one time. Had to run around and disconnect the battery to stop it from turning over. Check the solenoid first its easy and cheaper, but then I would pull the starter and have it checked...good luck
posted 03-05-2008 05:44 PM ET (US)
I'd hit the solenoid with the butt end of mid-sized screwdriver.
A hammer would be overkill.
I don't see how it could be the starter. If the solenoid is
posted 03-05-2008 05:51 PM ET (US)
Using the butt end of a screwdriver is fine too....that's about the impact level I was trying to describe above - a gentle tap rather than "hit it with a hammer".
posted 03-05-2008 07:54 PM ET (US)
I tried to reconnect the ignition switch.. and I don't know if I got it straight the first time. I get no power anywhere now. Could I have blown something like a fuse?
posted 03-05-2008 08:22 PM ET (US)
Let me add to that. Since I didn't have a diagram, I figured I could I identify which pair did what with a jumper, then attach to the ignition switch. I have a sinking feeling that this was not a good idea. :-(
posted 03-05-2008 08:26 PM ET (US)
It is likely you fried a fuse. I'd check all in-line fuses...if it is for the starter circuit, it is going to be a pretty big (read: expensive) fuse. Try not to do that again!
Get a manual that shows the wiring diagram. Best $50 you will spend on that motor.
posted 03-05-2008 10:44 PM ET (US)
The starter cables from the battery to the solenoid and from the solenoid to the starter are not fused. Certainly, if they were fused, the fuses would be LARGE.
Let's see - 1 hp is equivalent to about 746 watts and with our 12 volt power, means about 62 amps/StarterMotorHP. That is the current required to RUN a 1 hp starter motor. STARTING the starter motor will take what? - maybe at least 50% more - or somewhere around 93 amps. Of course, these are for short periods of time, but that is why typically 2 - 3 gauge wire is used with no fuses. ----- Jerry/Idaho
posted 03-05-2008 11:29 PM ET (US)
I don't think there is any starter motor malfunction which could result in the starter motor powering itself. Electrical current to the starter motor is controlled by a special type of high-current relay called a solenoid. If the starter motor is always running there are only two reasonable causes:
--the solenoid high current contacts have fused and the solenoid supplies current to the starter regardless if its coil is energized or not, or
--there is malfunction in the solenoid coil circuit and it is being supplied with current, energizing the solenoid.
In order to diagnose and repair electrical problems you have to have:
--a good multi-meter that can measure resistance, voltage, and possibly current, and;
--an understanding of the basic principals of electricity
posted 03-06-2008 09:14 AM ET (US)
Get the FACTORY service manual. The aftermarket manuals tend
to be a lot of one size fits none text.
If you can get things failing again, pull the small wire off
posted 03-06-2008 07:40 PM ET (US)
OK here is the scoop. I got her running today! The engine ran great, even after a year of sitting. I got the wiring figured out with the help of the diagram on this site. It was a little weird because the difference between the two "M"s on the ignition switch were not obvious and the switch had an "A" AS WELL as an "I", so not standard at all. Some say the starter motor does not have a fuse, maybe not, but the starter motor solenoid does. It is 20amp, and it was blown. I replaced that, wired the ignition switch, made sure the battery had a full charge (I need to replace it, got her cranked up and she ran like a champ! There are some minor issues I need to clear. A couple of wires for nav lights and the fish finder are pulled out but that is easy. I also have not installed the new starter solenoid, but something makes me think that sitting for a year in the humid Florida climate made it sticky and that use should get it doing its thing again.
One more question, I have the habit, after using the boat, of not only flushing the motor but also removing the cowling and coating everything in their with a light even coat of WD-40. I've always done this. Is this a good practice?
Thanks to all of you for the help. Can't wait to take the family for a cruise in a few weeks.
posted 03-07-2008 12:07 PM ET (US)
rayblnc - the blown fuse on the starter solenoid coil blew for a reason - something shorted within the solenoid. A solenoid is very a simple device - just a coil of wire that is basically just a big switch - for the large current required of the starter motor. One should have extra fuses in the tool-box - but, if it were mine and since that engine can not be started without the starter operatable (unless it can be pull-rope started) - I would replace the solenoid. They are not all that expensive - and it could eliminate an unpleasant experience. --- Jerry/Idaho
posted 03-07-2008 12:31 PM ET (US)
wd-40 is not bad (at least you are doing something) but after a while it leaves a dark brown mess (cooks on your engine probably from the heat of the engine) Look at another product/products CRC, 3M, Blaster, Blue Bloc etc, ...good luck
posted 03-07-2008 01:11 PM ET (US)
The fuse could be blown due to a miswiring that's since been fixed.
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