J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Warm starting problem. Anyone run into this problem ?

I decided to start a new thread on this given that I now have a better idea of the problem, sadly the solution still evades me.

First the problem. At the dock, when the motor is cold, I can fire it up easily using either battery with zero issues. However if after motoring for half and hour (or more) and dropping anchor or going for a sail once the motor has been shut off for 10 minutes or more it cannot re-start unless you manually "jump it" from the starter solenoid directly to the starter_in which case it will fire up instantly. In other words, it seems like there is a problem somewhere between the ignition and the solenoid that only seems to exist when the motor is is still warm. If the boat sits overnight at the dock, of course it always start fine when cold using the key in the ignition.
To date I have done the following in trying to resolve this issue_..
Replaced the ignition
Replaced both batteries with new
Cleaned all battery leads and the battery ground to the motor
Checked, cleaned and tightened the connections on both the solenoid and the starter.
Checked out the battery switch
Tested both of the batteries and alternator output and all is well.

I have no idea what to try next. Any suggestions would be greatly appreciated.

Many thanks in advance.

I had a similar problem with a car, it turned out to be a bad battery cable--it was corroded internally and would get hot at the bad spot when used due to the added resistance from the corrosion.

You might want to check the cables; the bad spot may feel stiff or brittle when you flex it.

It may be that the solenoid on the starter swells when it is warm and drags enough to keep it from making contact because there is less power available from the starter button from line loss, than there is on a jump. There is a Brazilian solenoid that costs a lot less than the Japanese one. A good starter shop should know about that.

That is an excellent suggestion, not to mention a relatively inexpensive item to take on next. Thanks for the idea_.very helpful !

Thanks for that as well_..I will try a new battery cable first and if that does not solve the problem the solenoid will be next.

Scott,
I assume that the engine does not turn over when you are attempting a "warm" start?

Do you get any sound when you turn the key? A click or clicking sound?

It could be the solenoid.

No click or clicking sound can be heard. You basically turn the key and nothing happens, no noise, no engine turning over. I was thinking the solenoid but one friend who is a car mechanic said that is likely not the case if the solenoid consistently works when the engine is cold and also works when it is jumped. However the idea that the engine heat is affecting the current solenoid is one that we had not considered either_..

So I understand what you are by-passing.... Are you forcing the starting solenoid on with +12V, or taking +12V directly to the starting motor with +12V directly from the battery to the starter? If direct, that is a boatload of current to jumper.

Build yourself a temporary test starting switch. Use standard lamp cord or an old extension cord long enough to reach from the engine to the companionway opening (or engine control panel). Cut off the plug and crimp on lugs that will fit on the starting switch side of the starting solenoid, and the other on the +12V supply side of the solenoid. Attach it to those points. At the other end mount a momentary contact switch. You should be able to manually engage the starter with this setup and effectively eliminate the wiring to the engine panel and switch as a possible source.

I have been basically just using a long handled insulated screw driver to jump the current from the solenoid directly to the starter - this has worked as an interim solution. I am going to test the battery cable idea first_I can simply use a jumper cable to do this and then I will try making a dummy switch (as you have suggested) and will try that second. Failing that I will try taking on the solenoid.

The part with the wiring that I can't figure out is why it works perfectly when cold, but not when hot. It's figuring out mysteries like these that better clarify why in the old days boats were often referred to as "she"_..

Just for clarification - have you actually turned the battery switch off then back on when the motor was "warm" - then tried to start it? Why I ask is that maybe the solenoid may not be fulling opening until the current is cut - turning off the battery switch when you leave the boat.