Solenoid?

[diamonddave]

After running my 1977 Peterborough with 188 HP Mercuiser for an hour or two anD I shut it off, if I try to start it while engine is still warm/hot it will not start. I jump the solenoid to starter and it fires up no problem. My car nut friend tells me to change out the starter/solenoid with automotive equivalents, but after reading all the posts here, I don't think thats such a good idea. Could the solenoid be intermittently not working, when the engine is cool/cold it fires up fine. Thanks

 

[dalauer]

Re: Solenoid?

I had a similar problem with my 1994 Mercruiser 5.7L. It would start when cold (although sluggish) and not at all when the engine was warm / hot.<br /><br />I traced the problem to a bad starter. Replaced it, and it works great.<br /><br />DaL

 

[Walter]

Re: Solenoid?

Resistance creates heat...heat creates resistance.<br />Electrical components often won't fail when cold...but once they get warm...poof.<br /><br />Does your 188 have a "slave" solenoid in addition to the starter's solenoid? If so...which solenoid are you jumping? The slave solenoid usually mounted to the back of one of the exhaust manifolds. It is controlled via the ignition wire...that is...when you turn the key to crank the engine...the wire from the key switch sends a 12 volt signal to the positive post of the slave solenoid coil. Once engaged...the slave solenoid sends 12 volts to the starter's solenoid which allows the starter to crank.<br /><br />The slave solenoid contacts (large terminals) can become dirty/corroded...and although the solenoid is engaging...it's not passing enough current to the starter solenoid. When this occurs...you should still hear the slave solenoid "click". If it doesn't click...either the solenoid coil is bad...or there isn't adequate voltage at the positive side of the coil to engage it. Also...you need to insure the ground side of the solenoid coil is grounded properly.<br /><br />Of course...you can only do these checks when it's in the failing mode... If the slave solenoid is in good order...and sending the proper voltage to engage the starter solenoid...then it's possible the starter solenoid or the starter itself is bad. <br /><br />If the problem reoccurs regularly...you shouldn't have much difficulty isolating the fault.<br /><br />Good luck...<br /><br />Walt<br /><br />PS...You should use marine grade electrical components...they're sealed to guard against igniting gasoline vapors.