blowing starter solenoids

gator-24

Cadet
Joined
Apr 27, 2003
Messages
17
i have a late 70s mercury 70hp 3cyl.. i have went through 3 starter solenoids in 2 weeks..every time i use my boat the solenoid blows..any suggestions also battery dosent seem to be charging i do have tach signal so i dont think the rectifier is bad..thanks
 

Clams Canino

Commander
Joined
Jan 10, 2004
Messages
2,179
Re: blowing starter solenoids

Starter has shorted windings and presents a big load, killing the solenoid.<br /><br />There's a couple rectifier failures that will let the tack work. Or you have an ongoing current drain.<br /><br />-W
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: blowing starter solenoids

Which part of the solenoid is failing? The connection between the two large terminals or the solenoid coil? If the coil is burning up, the starter is not causing that. Check to make sure you are getting 12V solenoids and not 6 volt look-alikes. Remove the starter and take it to an auto electric shop (starter/alternator rebuilder). They will test it and rebuild it (if its rebuildable). Much cheaper than a new starter.
 

gator-24

Cadet
Joined
Apr 27, 2003
Messages
17
Re: blowing starter solenoids

if its not the starter then what else could it be??
 

gator-24

Cadet
Joined
Apr 27, 2003
Messages
17
Re: blowing starter solenoids

how do you see what part of the solenoid is burning up..you cant take them apart can you..thanks
 

ricksrster

Commander
Joined
Jun 19, 2005
Messages
2,022
Re: blowing starter solenoids

The solenoid part no. you should use is 89-853654A1.
 

Motor Boater Bill

Chief Petty Officer
Joined
Jan 29, 2005
Messages
488
Re: blowing starter solenoids

Well, if the solenoid is dead you can certainly "take it apart" using Mercury "special tool" number 3-lb-sledgehammer. And goggles. Or you could test the windings with an ohmmeter. But I think the disassembly sounds interesting.
 

gator-24

Cadet
Joined
Apr 27, 2003
Messages
17
Re: blowing starter solenoids

i took it apart the copper peice that touches the big terminals looks a little burnt..the coil peice seems fine..
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,270
Re: blowing starter solenoids

Copper piece suppose to have arc burns, normal. I think you have a connection problem and not a solenoid problem. When you change out the solenoid it makes a connection for a bit then loses it again. Replace the solenoid with one of the old ones and with a meter, make sure you are getting a ground to one small terminal and power to the other.
 

gator-24

Cadet
Joined
Apr 27, 2003
Messages
17
Re: blowing starter solenoids

this is whats happening..when i put the first new solenoid in..i went on the lake motor starts fine..shut motor off..go to start nothing..jump across solenoid to start..motor starts..shut it off..starter stays spinning..has done this same thing all three times..thanks
 

ricksrster

Commander
Joined
Jun 19, 2005
Messages
2,022
Re: blowing starter solenoids

You might have a problem with the wiring at the ignition switch. Check those connections for loose or broken wires.
 

murphyjh

Cadet
Joined
Dec 19, 2005
Messages
8
Re: blowing starter solenoids

You may be damaging the solenoids by overtightening the large cable nuts. This tightening can pull the stud, and the contact inside, partly out of the solenoid body. The moving contact inside then can't reach this "submerged" fixed contact. Look at the large studs with the wires off to see if the metal flange on the stud is higher than the surrounding plastic. If so you may be able to push or tap it down flush to fix the solenoid. To prevent this problem, always use a close-fitting washer first on each stud. This will apply tightening forces to the metal flange, and will not pull the stud outward.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: blowing starter solenoids

Next time the starter stays spining, connect a test light to the small terminal on the solenoid and the other end to ground. If it lights you have a wiring or ignition switch problem thats causing the solenoid to stay engaged. Blowing is a term used rather loosely when an electrical part burns out. Your solenoid is very likely not burning out. In fact its very likely its not the problem at all.
 
Top