The Stovebolt Site Forums The Shop Area Engine Shop 1950 3600 : Why is it so difficult to start?

I've been having lots of fun driving my 1950 3600 around but it is having problems. A few weeks ago, I drove it to a truck show about 150 miles away. It ran fine and started every time I needed it to except for on the return trip. I had probably put on 400 miles or so by then and I stopped to get something to eat and when I tried to start to continue the trip home, it would not catch. Eventually I killed the battery but fortunately, the parking lot was slightly inclined and I was able to get it fired up (immediately I might add) when I started it rolling down the grade and popped the clutch. Got home and found that the fan belt was a bit loose after I had bought a new positive battery cable for it. Yesterday I tried to go to another truck show about 100+ miles away. I was about 40 minutes from the show and had to stop rid myself of the used coffee and when I tried to get it started again, it would not go and again I killed the battery. I tried the pop the clutch thing again but I didn't have much of a hill and ran out of that quickly. I continued on in my friends truck and then we returned in the early afternoon to mess with mine. We jumped it using his 12V truck (mine is 6v) and it started rather quickly. We drove a short distance and then decided to pull over for lunch but this time I found a nice long steep hill park on. After lunch it would not start again with the starter so I started it rolling down the hill and popped the clutch. Started right up and I drove for about an hour and a half to get home.
This morning I tried to start it and it would only crank over a few times but not start before the battery gave up. Battery is about month or less old. So now I have the charger on it and tightened the fan belt even more. I know the generator works as the headlights get brighter when the engine revs. I have also noticed that charger shows a current draw of about xxamps. It never seems to go lower than even after 5+ hours of charging.

So I guess I have two problems to fix.
1. Why will it not start easily with the starter but quickly with the pop the clutch method?

2. Is my battery really charging? With the ignition in the off position, I took a meter and tried all the exposed lugs I could find to see if something was shorting out with no luck. Only place I found any voltage was at the fuse block for the stop light and I think that is supposed to be hot even when the key is off.

Thanks for any ideas or suggestions!

IMHO the reason your truck will not start is low voltage at the ignition coil. If you have amperage to the starter and it is turning over, then check your voltage at the coil. Correct the high resistance problem. Key switch/contact between wiring terminals. I have found high resistance at the points causing this problem. Clean with newspaper and see if it starts. Lube on the points from crankcase pressure can cause the high resistance on the points. Mtneermike

First, if you don't have a good voltmeter, get one. For general troubleshooting, a simple digital multimeter will do. If you're planning to get into adjusting a generator/regulator system, an analog meter with a sweep needle instead of a digital readout is better.

Check the voltage at the battery posts (not the cable terminals)with the ignition off. It should be slightly above 6 volts, maximum 6.3. Next, with the ignition off, crank the engine for 15 seconds and measure battery post voltage while still cranking. It should not drop below 4.5 volts for this test. If the battery fails either voltage test, charge it fully and retest. Batteries can be bad right off the shelf- - - -"new" is a relative term, especially for 6V batteries that might sit on the shelf for months before they're purchased.

Next, measure the voltage at the big starter cable while cranking. It should be within 1/2 volt or so of the voltage at the battery. If not, you have dirty connections and/or too-small cables. 6 volt systems simply will not tolerate voltage drops. All connections need to be clean, no make that CLEAN and TIGHT and as big a cable size as you can find!

Next, check the voltage at the coil + terminal while cranking- - - -it should also be within a few tenths of a volt of battery voltage at the posts. If not, trace the wiring back through the ignition switch, ammeter, and ammeter power connection at the starter, looking for loose or dirty connections and/or voltage loss through the ignition switch.

Finally, check the points in the distributor- - - -they need to be clean and gapped properly, and the ignition timing needs to be adjusted correctly.

You're probably going to find battery problems and/or dirty cable connections. Good luck!
Jerry

Along with the electrical items mentioned above, check this link:

http://www.thecarburetorshop.com/Troubleshooting.htm#Hardstarthot

Jon.

As Jerry has mentioned make sure all connections are clean, I.E. cleaned with emery cloth till it is shiny, I have used never seize on battery connections for many years. It is conductive, helps prevent corrosion, and allows the fasteners to come apart when the time comes. There is a special electrical stuff you could use as well, but it won't work any better, and I always have 2 or 3 cans of never seize around. I am using the standard off the shelf cables from O'reilleys that are intended for 12 volt systems. I don't remember the gauge right off hand, but I do know they are about 2 sizes smaller than many people think you absolutely need. But given I have been using them for about 3 years and my truck starts by basically stomping the pedal to the floor, and releasing it. I don't think the larger size is necessary. But then I may just be lucky. It does sound like the battery is not getting fully charged, but you need to have quantitive measurement, the lights getting brighter just means the generator is putting something out, but the fact it won't start with the starter says it isn't putting out enough voltage. Or at least it isn't getting to the battery.

I think we might be missing something here. Gazz, you didn't say that when you initially tried to start it, it turned over really slowly. I believe it just "wouldn't catch". With both my 51 1 Ton and my 38 Master, starting after a 20 minute pause on a hot day requires a special technique. What I do is slowly put the gas pedal to the floor with my left foot and leave it there for about two minutes. Then without moving the gas pedal, I turn on the ignition and hit the starter with my right foot. It will then catch right away. The problem I think is caused by percolation of the fuel in the carburetor.

Thanks for all the suggestions.
After being on the charger for maybe 3 or 4 hours and little to no change on the ammeter of the charger), I cleaned the points (which are new and properly gapped) with the newspaper as suggested above. It fired right up. I took it for a drive around the block, probably at least 5-6 miles and when I got back home, I shut it off and waited about 5 minutes and then tried to start again - it fired right up. When I resurrected this last year, I took the battery cables off and cleaned all connections to bare metal. Then I used the hi tech dielectric grease that I have from my former job at all connections. Last week, I replaced the positive battery cable that was made for me by NAPA - they know it is for a 6v system and I certainly hope that they used the heavier gauge wire as I requested. I measured the voltage at the battery with my Triplett analog meter and it shows just above 6v before I connected the charger. I didn't check it after charging.
Three weeks ago, I had this at a friends shop who basically went through the ignition system. New points and condenser, plugs, rotor, cap, wires and coil although I had already replaced all of that earlier this year. It would start just like I remember it starting 30 years ago. So it seems that it does not like to start when hot and after being driven for several hours. The carb does get somewhat warm after several hours but my mechanic friend does not think that is the issue.
When I have some help available, I'll try some of the other suggestions.

If it's 6 volts, you need 2 gauge ground strap between the engine and the frame. Then 2 gauge negative battery cable. Most people replace with 4 gauge because the 2 gauge is harder to come by. 6 volts requires two times the current capacity of 12v. Good clean grounds are critical. Of course same attention to the pos side.

Gazz, I think you might give truckernixs suggestion some more thought. My truck always starts right up. Driving around town running errands, start it, shut it off, start it up, shut it off, not a problem. But if I run thirty miles or more, especially on a hot day, and then shut it off and let it set for half an hour to maybe an hour and a half, it doesn't want to start. I know your mechanic friend doesn't think that's the issue, and he might be right, but it would be worth it to give truckernix's idea a try. It works for me. In fact, I use the method linked to by Carbking. TRY IT!

I've considered pulling the throttle knob out about half way after shutting down after a long drive, so that, at start up, the throttle is already open to clear out the excess fuel without pushing the gas pedal down and introducing more fuel. Just a thought I might try out one of these days.

What do you guys think?

I figured there may a technique that I needed to follow to get it to start right but have not found the magic combination. I will try truckernix's method next time I run it for a bit.

Just a note...watch out with that dielectric grease. It is an insulator. If you choose to use it, apply it only after making the connection. A car buddy of mine, who is a mechanic, ask me why his tail lights were giving him a fit. Turns out he used that stuff before making the connection. I prefer to use copper anti-seize on my connections and spark plug threads.

DITTO

That is news to me on the grease. We used it every where on high voltage low current connections for the reason that we wanted a good connection. All the EE guys said it was great stuff for electrical connections anywhere and I used it for years on my boat (salt water) with no issues.

I have used dielectric grease on the contact area of battery wire terminals and battery posts with no adverse effect. It is said by some to be an insulator. Maybe it is until the grease is squished out upon tightening of the fastener, thereby resulting in metal-to-metal contact. And at the same time provides corrosion protection of the connection.
Carl

Di-electric grease is non-conductive and is very good on modern circuit boards. It allows for a clean (isolated) connection and no "cross talk" on circuit boards.

EE guys are usually more concerned with circuit board connections.

http://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm

The conductive grease is an antioxidant and provides corrosion protection.

http://www.permatex.com/products-2/...atex--copper-anti-seize-lubricant-detail

http://www.specialized.net/Specialized/CP8TB-Thomas--Betts-KoprShield-Compound-8Oz-2265.aspx