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Posted By Discussion Topic: hot restart problems -- page: 1 2     mike39 08-06-2013 @ 4:50 PM reply profile send p.m. Member Posts: 34 Joined: Jan 2012 Hi all, Im working with a 40 coupe. Stock and 6 volt. Starts fine cold but after its warmed up it wont crank fast enough to start. Have to use a jumper box. New Interstate 750 amp battery. New repro cables and solenoid. New DB starter. All connections are good as far as I know. Ideas ? Don't want to go 12 volt. Thanks, Mike ford38v8 08-06-2013 @ 8:19 PM reply profile send p.m. Senior Posts: 2765 Joined: Oct 2009 Mike, No need to go to 12 volt, so first off, check to see that your "new" cables are not 12 volt cables. 6 volt systems require 1/0 or 2/0 cables, including the ground straps. Put your hand on the insulated cable running from solenoid to starter. It shouldn't be warmer than the firewall itself. Correct gage cables with good solid clean connections are needed. The starter (What is a DB starter?) must be properly grounded also. Hot starts can be a problem from both electrical and fuel reasons. Modern fuel has a very low boiling point, and will evaporate out of a carb bowl during a lunch stop. You might also check the power valve, especially if the engine has backfired through the carb recently, which blows out the delicate diaphram in that valve. Cranking at any speed will not start the engine without fuel, and it takes a while for the pump to deliver to the carb. A well tuned flathead needs only a short push and a bump in 2nd gear to start, so speed of cranking is not the issue for that reason. Faster cranking does help the fuel pump to deliver faster, however. The coil is robbed of adequate voltage during engine cranking, that is the reason you'll see many engines start only at the instant that the starter motor is released, thereby freeing up the available voltage supply to power the coil. You may bypass the resistor on the firewall momentarily to provide the voltage that the staerter motor denies. You don't want to run with this higher voltage though, as it will burn the points or the condenser, and will shorten the life of the coil. Alan This message was edited by ford38v8 on 8-6-13 @ 8:19 PM TomO 08-07-2013 @ 6:40 AM reply profile send p.m. Senior Posts: 7256 Joined: Oct 2009 Slow cranking is due to inadequate voltage to the starter, poor grounding of the starter or a bad starter. If you have a voltmeter, you can do a voltage drop test to check out the connections and cables. You should also check that there is no paint on the starter mounting surfaces. This is the grounding connection for the starter. Tom supereal 08-07-2013 @ 10:06 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Hot starting problems almost aways are due to low voltage at the coil because of the starter load. If the coil input voltage drops below three volts, the output is too weak to fire the plugs enough to restart easily. Some install a switch to bypass the resistor, but because my old memory doesn't always tend to turn it off, we use the attached device to promote reliable hot operation. mike39 08-07-2013 @ 5:17 PM reply profile send p.m. Member Posts: 34 Joined: Jan 2012 Thanks guys, Will do a little more checking. DB starter = DB electrical Pretty good starters for cheap. Find them on the net. TomO 08-08-2013 @ 8:47 AM reply profile send p.m. Senior Posts: 7256 Joined: Oct 2009 Mike, I checked their site and they do not give the current draw of their motor. It may be drawing more current than your battery can provide, resulting in turning the engine over slow. The Ford starter draws 150-200 amps and with a good battery and connections should turn your motor over very fast. I suggest that you use a good voltmeter to check the battery voltage with the starter turning and a voltage drop test of both the positive and negative circuits. Your battery should provide at least 5 volts at the battery to the starter. You should not have more than .1 volt drop at each connection, the total voltage drop from the battery to the starter should not exceed .5 volts, but in a good system, it will read about .3 volts. Tom TomO 08-09-2013 @ 7:43 AM reply profile send p.m. Senior Posts: 7256 Joined: Oct 2009 Mike, you may also have a timing problem. Check the cranking speed with the ignition off and when the ignition switch is on. If it cranks slower with the switch on, have your distributor checked over by a qualified mechanic. Tom mike39 08-10-2013 @ 4:23 PM reply profile send p.m. Member Posts: 34 Joined: Jan 2012 Tom, We tried the ignition off and on, no difference. A local guy that's good with electrical says he can modify the starter so it will crank it faster. We will see.....Gonna try the hot start wire too. Mike supereal 08-10-2013 @ 8:26 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Trying to boost starter power usually results in a destroyed unit. As noted, if all cables are of sufficient size, connections are clean and tight, and the battery is strong, yet the starter is slow, it is time to look for a new or rebuilt unit. Be sure you have the brace between the starter and an oil pan bolt, as torsion can bind the drive in the ring gear. Worn bushings allow the armature to drag on the field shoes. TomO 08-12-2013 @ 8:29 AM reply profile send p.m. Senior Posts: 7256 Joined: Oct 2009 Mike, In that case, use a good voltmeter to check the cranking voltage at the battery and the voltage drop from the battery to the starter. If you need help with the voltage drop test. let me know. Tom

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