Category: Ask the Guru

ATG (JanFeb14) - Marathon Ignitor

Q: BH From R.I. Asks: How do I bench test a Marathon Ignition system?

A: BH, the way I do that is by the use of a Marine Plastic Board and mount the following items. Use a 10597 Pulsar Coil, 5121 Coil, 9174 Spark Plug Wire, and either or 10594/10595 Igniter. Add a Normally Open switch for activation. Add a Plunger style solenoid like you would find on a Carburetor shut off. On the end of the solenoid plunger glue, solder or crimp a flat piece of metal. Connect a spark tester onto the coil wire and ground. It is important to gap the Pulsar magnet to the solenoid flat metal piece. You may need to adjust that a few times to get it to exact. I placed mine at .030” and at times need to close that gap a tad or open it a tad. You just have to make adjustments as you go with that part of it.

Looking at the system and how it works will give you some insight as to functionality. Any ignition system must have a power source of 9.6 volts up to 16 volts for proper testing. Confirm that first. You can purchase a 12 volt power supply from your local Radio Shack or electronics outlet store. Once an applied voltage of positive and negative are in place. A positive voltage is applied to Igniter and coil. Battery negative (ground if you will) is applied to the base of each component and direct to the igniter internal circuit. By activating the solenoid the magnetic field causes a  signal (voltage) to the igniter. This signal then causes a voltage to the ignition coil. Then you should see a good solid blue spark on the tester. The faster you can “click” the solenoid on and off the faster the spark will be. So imagine on a spinning engine at 3000 RPM’s how quickly that all happens! So you can kind of think of that circuit as a “pulsing” voltage. So if you have a failure of spark your next step is to confirm potential voltage at each point in the diagram. It is next to impossible to see the voltage pulse but you can see a spike. That spike usually indicates the component is sending a signal (voltage). But that voltage must make and break in order for the system to work. Base the test stand on a working set of components before you use it on suspect parts. I tested over 100 igniters with this and it does help with bench testing.

Interchange from 10595 to 10594 to 10595. Both units use the same Pulsar Coil and this makes both units compatible with the system. The one noticeable difference between the two units is the D wire color. 10595 is a black wire and the 10594 is a red wire. All other wires are matching colors. Cut the wire ends and add the appropriate connectors to each wire and route each wire to the correct component in the system.

ATG (NovDec13) - Kids Carts

Q: GL writes: You talk a lot about big kid toys, but what about for actual kid cars? What is a cheap way to make a kid car speed control?

A: I find this to be an entertaining question and one I get quite often. So below is about as simplistic as     it gets! There can be a lot of variations to this dependent on size of car and weight. Relays can be used for light duty instead of solenoids as an example. You just need to calculate the load and go from there. It has quite often been mentioned to me the kids see Dad/Mom driving around and they want one like Dad/Mom. So I hope this helps.

Battery positive is applied to all four solenoids. At the same time battery positive is applied to the foot pedal switch. When the foot pedal switch is closed battery positive is applied to all four speed switches.

Let’s say 1ST speed is selected. When the foot pedal is pressed battery positive is applied to the 1ST speed solenoid. The contacts inside the solenoid closes and diverts that positive voltage to R4 resistor. Because the other solenoid contacts are still open positive voltage flows through all the resistors. From R1 connection positive voltage flows through A1, A2, S2 and out S1 to battery negative. As each solenoid speed is selected the path of resistance through the resistors decreases and speed increases. Very simple and easy to do. If you want to spend a little extra you can do the same thing with a Solid State System. You can make a small car out of GO-Cart frames. Welded tubing and pre-existing kits cars you can find on-line. Should be a fun little project for a weekend or two. Enjoy!

Tech Tip: it is strongly advised to add a fuse on either the positive or negative main connection on the power side. The resistors allows you to have control of the car’s speed!

A good resistor to start with is part number 2699, motor 7954, solenoid 1128 and 9074 switches, or 2454 switches. Look for old junked golf cars and take parts off it. In other words look around there are used parts available. Use a belt driven drive unit off a lawn mower or industrial car. Be creative on that part.

ATG (SepOct13) - Explaining air leaks

Question: Jason writes ‘what is an air leak”? What does it mean?

Answer: You will hear that mentioned a lot when referring to two cycle engines. However that does apply to four cycle engines as well. Sense you have a vintage using a four cycle engine we will focus a tad more in that direction.

An air leak is basically the same thing as a vacuum leak and is just more of a term used in area’s we sometimes do not recognize as an vacuum area. Vacuum area’s are carburetor gaskets, carburetor shaft, mounting adapter, seal, fuel pick up line at tank, tank siphon tube, clamp, and engine block hose connections.

Air leaks are more of an area like air cleaner housings, air cleaner hose, or some sort of air inlet to the carburetor. The bottom line is both terms affect engine performance Think about air to fuel ratio for a moment. If we have too little air we have a rich fuel mixture and poor power. If we have too much air we have a lean fuel mixture and cannot have good engine performance. You have to have a good balance of air to fuel for good performance. With that said you can usually tell (based on good compression, spark, fuel and exhaust) some sort of air leak is draining engine performance.

Look for black soot on the spark plug, that is one good sign. Look for hard starting or not starting at all. Look for erratic idling or smoke out the exhaust. Sounds like the engine is misfiring. Loss of power is seen. As you can see this all resembles ignition issues, carburetion issues or even compression issues. You have to rule out those things first. Once we have then we look at those pesky air leaks or vacuum leaks.

Air leaks, look for loose hose clamps or an inlet hose with a hole in it. Or even a clasping hose simulating a leak or ignition problem. Look for cracks or holes in the air cleaner housing. Look for an air cleaner lid that is improperly seated, I see that a lot. Look for an air filter that is full of debris simulating an air leak. Look at any sort of crank case ventilation tube or hose with a hole in it or loose clamps.

Vacuum leaks can be, a seal, or fuel pick up tube that has fallen off. Fuel outlet hose from fuel tank sucking air around the mounting grommet. Throttle shaft sucking air or mounting adapter. Any place that has to do with vacuum you must check. Never rule out the little things and only concentrate on the larger common items. Air leaks are a part of troubleshooting a fuel system. So do not over look this. One other area that is often over looked is the gas tank cap. It has to be vented to the atmosphere or it can fool you making you think we have ignition issue or vacuum leaks. Rule things out and follow procedure and don’t just get one thought in your mind look at the whole picture.

ATG (JulAug13) - Can I remove my governor?

QUESTION: SE from Texas writes: How can I get rid of the governor?

ANSWER: That is a common question. I do not suggest the removal of the governor and will not offer how to disconnect it. However, I will tell you how it works and how to adjust it. The governor is there for a reason. And that is to protect your engine from a over “rev” resulting in damage to engine or operator. For me to tell you to remove a safety devise I cannot.

The governor on gas golf cars works off centrifugal force or mechanical force and is usually located in the Drive unit. A balancing act occurs as engine RPM is raised causing pressure against an external spring. Pressure and spring tension cause a restriction in engine top RPM’s (Revulsions Per Minute). By increasing this spring tension we can raise the RPM level. By decreasing the spring tension we lower RPM level. This is all based on a working set of linkages and throttle adjustments. Meaning it is key to have complete throttle opening as well as closed idle settings. If you never have full throttle how can you ever have full power! So at engine off you need to check for full throttle down with accelerator and check the opening of the throttle plate. With the accelerator pedal fully up you should see an at rest of the throttle plate against the idle adjusting screw. Kind of think of it as you would a potentiometer as a position from at rest to full wipe. Once you have made all the proper throttle open and closed positions then you can adjust the governor. That is the number one part of governor adjusting that is often missed. Each manufacturer has top governor settings listed in their service manuals so refer to that for correct settings.

Common question two is tied into this same question as above. “My gas powered golf car does not have any power”? As you can see the governor and throttle opening has a lot to do with power. Based on those settings being correct then we move on to other area’s of power loss.

1) Low compression can be a source of lost power

2) Intermittent spark can be a source of lost power

3) Water in the fuel system can be a source of lost power

4) Air leaks or vacuum leaks can be a source of lost power

5) Mechanical “drag” such as brake drag, tire pressure, wheel alignment ETC….

6) Charging system that is always in full charge mode

7) Restricted exhaust

8) Wrong drive belt

9) Drive clutch filled with dirt and debris

10) Driven clutch spring or sheave movement wrong or broken

11) Drive or driven clutch sheaves worn out restricting belt movement

As you can see from this partial list it is never just a cut and dried one answer of area sort of thing. There are multiples and you have to follow procedure to recognize or find the exact cause. But from experience the most common cause is failure to have full throttle and or air leaks. Briefly air leaks (vacuum leaks) can be in the air cleaner box, hoses, carburetor mounting, or throttle shaft. I am not saying to jump directly to those area’s I am just saying that is most common. Just do not rule out the other area’s and look for quick fixes.

If all is well you can always add torque gears or driven clutch torque spring for added power. This eliminates the need for drastic changes like governor removal.

ATG (JanFeb13) - POTs, ITS & V-Glide

Question: PA in Minnesota writes; I hear a lot about POTS, ITS, V-glide and all sorts of values, tell me what all that means?

According to Roger: What is meant by those short terms is “throttle inputs”. Car manufacturers use different inputs as part of what they feel best suits a control system they wish to use. Accelerator, linkage and location on the car can play part of why a particular throttle input is used. Pricing and Controller can play a part as to what input the manufacturer may use. So it is not some sort of part that is pulled off the shelf and put on a car (without thought going into it). Going one step further, we call the whole assembly an accelerator.
One POT (potentiometer) that is used and is most common through the years is a rotated shaft that moves across a carbon trace either in a clockwise or counter clock wise rotation. Most common resistance on this type of POT is a 0 to 5K or 5K to 0 wipe. Wipe just means the movement from beginning point to ending point based on accelerator pedal depression. A POT can have many resistance values so you must look at the manufacturers specifications to determine the POT value for the car it is being used on. So you can think of this type of POT as being a variable resistor that is mechanically activated.
ITS (Inductive Throttle Sensor) just means it is a voltage controlled input. Again, with this type you have to know the manufacturers voltage inputs before testing. There are different configurations of this Sensor so do not be fooled by how it looks. An Inductive Sensor does the same thing as a POT, except it uses voltage variances to change the speed of the car.
V-Glide (multi-step pot) is just another form of a resistive wipe (similar to a POT) but uses a set of resistors in series and uses a carbon based brush and copper contacts to vary a step by step resistor alignment for car speed. Again it can be either a 5K to 0 or 0 to 5K wipe. Some are a 2 wire circuit and some or a 3 wire circuit. The third wire on some systems is used to supply a negative to the assembly. Again, you must know what the manufacturer of the car is using.
Testing and trouble shooting POTS or ITS is just a matter of knowing value and having a VOM to test with. Purchase a good quality VOM (Volt/Ohmmeter) that has DC voltage ranges of 20 to 200 volts (DC). Resistances ranges of 200, 2000, 20K and 200K ranges (digital meters). Digital is a little easier to use than Analog but that is your choice. Just make sure the Analog meter has an RX100 scale. Some POTS are very difficult to connect to so it is advised purchasing a set of self penetrating clips as well. As the car market changes you will see more and more of a need for self penetrating test lead clips.
Having the correct input to a controller is very important. The logics of a controller can only operate based on the input it sees. As an example a customer may have a controller using a 7K to 1K POT input. A controller is mounted on a car that uses a 5K to 0 POT. The controller will sense that 5K potential and shut the car down. This is called high pedal detect and is a safety feature built into a controller. At 5K the controller sees a partial throttle condition (40% on). This particular controller has to see 6K to 7K for the controller logics to perform. Otherwise the system is shut down. We see this continually on our tech lines and returns. The market has produced many brands of controllers for speed and torque applications. This has expanded into a lot of stock control systems to speed and torque replacements. Doing so does create problems for technicians that did not do the installation. The installer sometimes may change a POT input to match whatever controller he may have in stock to get the install completed. So do not trust what was done before you as sometimes what the manufacturer actually put into the car may not be there now. This has become quite common so pay close attention to exactly what system is being used in the car. Test first, and than order is my suggestion for getting the correct part you may need to order. Freight back and forth in todays world can be expensive. If you need further assistance feel free to email me for testing procedures for your car.

ATG (MayJun13) - Solenoids on Gas Car

QUESTION: A.N. from Nebraska writes: You talk a lot about double solendoids on electric cars but nothing on gas cars that have the old 5306 key switch that never works. What can I do to replace that key switch, it keeps falling apart and I am frustrated with it?

ANSWER: The power circuit is battery positive to normally open side of solenoids. Selecting either solenoid 1 or 2 allows positive to flow out the jumper to F2 or F1 depending on forward or reverse mode. Let’s say for now we have selected solenoid 1.  Then based on that selection positive will flow out the orange cable to F2 and through the fields and out F1 to normally closed contacts on solenoid 2. Positive then flows through the cable to F2 and through the fields and out F1 to normally closed contacts on solenoid 2. Positive then flows through blue cable to A2 and through the armature to A1 ground. You just reverse the flow selecting solenoid 2.  NOTE: Wire colors vary as this is only guide.
You may choose what wire colors you wish to use. The sequence is all that matters.


ATG (NovDec12) - Clutch Pullers

UA from NJ writes: Explain what a clutch puller is

On golf cars it is a devise with a hex head shaft with a threaded area for inserting into a matching threaded hole on the clutch. Notice on the sample clutch pullers all of them have several things in common. All of them have a hex for socket turning, recessed shaft, and a threaded area.

It is that threaded area you have to pay attention to when ordering a clutch puller. Thread pitch size varies from manufacturer to aftermarket designs. You will see anything from a fractional pitch of 20 to metric pitch of 1.00 mm. That puller pitch has to match the same thread pitch that is inside the clutch pulling area. If you look at the 5700 clutch shown below, notice on the end there is a hollow threaded area for the puller. On golf cars that threaded area exists after you remove the mounting bolt. On some models you have to pull the dust cover to access the mounting bolt (picture 9035). Next you should put a dab of grease on the end of the recessed puller tip. This does two things as it adds lubrication and most of all you cannot compress a liquid. Understand you are literally pushing the clutch off the crankshaft. When turning the hex head with a socket again you have to pay attention to the puller thread sizing. On small thread size pullers do not use an impact for clutch removal! If you break that puller you are in for a total nightmare to get that clutch off. You can only apply 40 to 45 foot pounds of torque on the small ones.

You should always test the threaded area to make sure there is not any damage the threads. Sometimes it is wise to “run” a tap through the clutch threads. Over time the threads can rust or corrode from the elements. If you do not have tap sizes you should purchase those from any tool supply warehouse. One old saying is “use the right tool for the job being performed”.

There is a difference from O.E.M. to aftermarket clutches and pullers. Just by saying you have a1999 model whatever, how do you know that car still has the O.E.M. clutch? You have to physically look and measure to make sure of what you actually have. Aftermarket clutches for the most part do not have the same thread size as O.E.M. Model, serial number and MFG codes are only the start of the process. Again, it is like ordering a tie rod end. How do you know you need a LH end or RH end. Yep, you have to look. Clutches have fallen under the same category as, motors, controllers and other aftermarket parts. You just cannot order those types of parts based on model, serial number or MFG code alone. You have to look first then order.

Professional golf car repair centers understand all this and if you need assistance they will be glad to help you.

ATG (SepOct12) - Checking a Starter Circuit

B.H. from Ohio writes; What is a quick way to check the starter circuit on a gas Club Car

I assume you mean the engine is not turning over. I do not like in this format to just throw out a quick “this is what you do”. I like to take the time to fully explain things so in the event the “quick way” did not work. It is best to understand what is in the circuit and recognize how each component in the circuit works. This gives you a much clearer view of where to look sort of thing.

The starter system consists of the Battery, Conductors, Solenoid, Starter/Generator for the Power Circuit (Secondary). The Activation Circuit (Primary) consists of a Fuse, Conductors, Key Switch, Start Switch, and Neutral Lock Switch. You have to start trouble shooting with the Battery. Load test the battery and make sure it can maintain above 9.6 volts under load (A). If it does not check the cable connections and battery condition. Next check all the cable connections for proper connections and proper grounding. Check the Starter/Generator armature and field connections. Meaning remove A1/A2 connections and F1/F2 connections. Place an ohmmeter (low ohms) across A1 to A2 and you should read continuity. From F1 to F2 you should read continuity. If reading “open” than check the brushes, field windings and armature. Check each Starter/Generator terminal to ground (G) (low ohms). Each terminal should be free of a grounded condition. Any opens or grounds remove Starter/Generator motor for further testing and repair.

Primary circuit testing is just as simple. Understand that battery positive is applied through a fuse to the key switch (B). From the key switch battery positive is applied to the solenoid (D). Confirm that voltage is present. Battery negative (ground) is applied to the Solenoid from Neutral Lock Out Switch, and Start Switch (G). Confirm the Neutral Lock Out Switch is grounded and does activate NC (Normally Closed) and NO (Normally Open) contact positions. Same applies to the Start Switch make sure it activates from COM (Common) to NO (Normally Open) terminals. It is all about confirming voltage at each point, that simple.

Tech Tip: Specialty tools for the job.

ATG (JulAug12) - Testing Voltage

QUESTION: Roger what do you mean when you say “check voltage across the solenoid”? Voltage across battery? This confuses me..VA from NE

ANSWER: Sorry to confuse you and all this means is just what I am implying. You are literally testing voltage across a given point. Example is the solenoid. Typically you have four connection points. Two connections are for activation (primary) and two are for power circuit (secondary). So when I say I want you to check across the activation terminals (small terminals) I mean connect the black voltmeter wire lead to the small terminal negative input. Connect the red voltmeter lead to the small solenoid positive terminal. Meaning across the two terminals.

Why we do this is to see if we have both potentials present at the time of solenoid activation. If both potentials are present and the solenoid does not “click” the solenoid coil is open (replace solenoid). It is just that simple. If we do not read both potentials we are missing one and we have to find out which one is missing. At the same time you will not connect across the secondary (power circuit) as that will be a like potential (usually positive). So talking about “across” means a component that has two potentials present not one. A battery has two potentials, solenoid, light, coil, relay, horn, converter, and so on.


Connecting to just one terminal is checking only one potential. Meaning you have to find the other potential somewhere else such as battery negative or battery positive.


ATG (MarApr12) - Replacement Timers

QUESTION: TM from CAL Writes: I hear you talk a lot Part Number 30931 Auto-Timer can it be made to work on the car? DC Nevada

ANSWER: DC, this being a new product it takes time to finish completely. We have several reports of this unit working well on the charger itself. The 30930 36-volt version is a good alternative for 36-volt ferro-resonant chagers. So don’t forget there are two versions 36-volt and 48-volt.

I had so many requests for the 30931 to work on the car so I finally took the time to do that.

Procedure: Leave on-board computer where it is. Disconnect the main negative 48-volt negative twelve gauge lead wire going to the computer. Cut this wire close to the computer and move the wire to battery number six negative terminal or battery number four if you have a four 12-volt arrangment. Choose an area on the front of rear body leg area. Using supplied template mount the AT (auto-timer). Replace the key switch with a on-off-on double throw style switch. We found that part number 2690 works well by cutting dash hole large enough for mounting. Or you can use any kind of aftermarket switch that has the correct configuration. This works with key in the center position plug the charger in. Then turn key to left position and after a time delay the charger will begin. When complete the timer will shut off indication of a green light. Unplug charger turn key to full right the car is in run position and timer is disconnected.

Nothing else needs to be done to the computer as long as the car runs. If it does not run, we have by pass wiring for that as well. Below is the wiring configuration for the install.


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