Tech Tip #7 Spark Plugs-What Nobody Told You

By larryNo Comments

Tech Tip #7 Spark Plugs-What Nobody Told You

Spark plugs are one of the most misunderstood maintenance items on your welder. Read and learn!

Removing Plugs

First, clean out the dirt around the base of the plug with compressed air to avoid it falling into the combustion chamber. Remove the old plug carefully from a cool head with a steady continuous pressure. Be careful not to use too much force which could result in stripping of threads and/or breaking the top of the plug. Once out, inspect the plug for the condition of the installation and the color of the deposits. Wet, oil soaked plugs are a sign of excessive ring wear. Black fouled plugs are a sign of too rich of mixture (have the carburator or fuel injector system checked). The plugs should have a light gray color-a sign of correct fuel/air mixture. If the present plugs are going to be re-used, carefully clean the threads (with a wire brush or wire wheel), make sure the spark gap is correct, and apply a light coat of anti-seize.

Installing the Plugs

Use a wire type spark plug gap measuring tool. Check your owner’s manual for the recommended gap and then carefully thread in the new plugs by hand. Tighten with a torque wrench to the specs given below.

Torque Recommendations
  Cylinder Head
Spark Plug Thread Size Cast Iron Aluminum
Squared shouldered, Gasket Type 8-12 8-12
10 mm 10-18 10-18
12 mm 26-30 18-22
14 mm 32-38 28-34
18 mm    
or a one quarter turn after finger tight
Tapered Seat    
14 mm 7-15 7-15
18 mm 15-20 15-20
or one-sixteenth of a turn after finger tight

Once clean, re-gapped plugs are back in, check your wires. Rubber ignition wires will deteriorate after a couple of years from exposure to heat, oil, grease, and vibration. Weldmart ignition wires will last a lifetime Weldmart ignition wire carry a lifetime warranty to the original purchaser. These wires will go a long way to enhancing engine longevity.


Tech Tip #5 Welder engine water pump install tips.

By larryNo Comments

How to Install a Water Pump Pulley

1. Remove the old water pump from the engine and clean the mounting surface on the engine block.

2. Thoroughly drain, flush, and reverse flush your radiator and engine block to remove all scale and rust. If necessary have the radiator cleaned, recored, or replaced.

3. If you have to install a pulley, do the following. Measure the amount of shaft sticking out of the pulley. Normally you can tell where the pulley should be on the shaft the color shaft-it’s a dead give away.

4. Carefully remove the old pulley using a gear puller (a gear puller uses bolts-not puller jaws!  (Do not try to remove the pulley with a three jaw pulley, use only a gear puller that uses the bolt holes in the pulley.)  Check the sheaves for abrasions, crack, or nicks, replace if there is doubt. 

5. Remove the back plate on the pump. Using a steel block to support the pump impeller, press the pulley back on to the pump shaft with a hydraulic press. Make sure that the pulley is pressed on to the same place as the original pulley.  

6. Install the pump on the blocks with a new gasket.  Check all hoses, fill the engine with coolant, and, while running, check for leaks.

Misc Topics on Most Anything

Tech Tip #4 How to install a new head on your welder.

By larryNo Comments


Installing a new or remanufactured cylinder head is easy if you follow this step checklist. Read the whole list before you start!

1. Check head and block for flatness with a straight edge and a feeler gauge. The maximum warp should be 004 across the blocks deck and 002 across the head.

2. While the head is loose, check the spark plug hole or injector hole threads and retap as necessary.

3. Inspect the finish of the head; if possible, borrow a friend’s profilometer to check for smoothness.

4. Run a thread chaser through each cylinder head bolt hole, blow out with compressed air and wipe all surfaces clean with a solvent.

5. Bring the Number 1 piston up to Top Dead Center (TDC) using a dial indicator. This will facilitate timing later.

6. Install the head gasket correctly, front-to-rear, and in the upright position. Align the dowel holes into the dowels.

7. Apply teflon thread sealant  or tape to any head bolts entering the water jacket. Lightly lube the other bolts with an assembly oil. (a mixture of STP and SAE 40 is as good as anything you can buy off the shelf).

8. Tighten the head bolts following the procedures as specified . (Bolts are inexpensive. We supply new bolts to most of our diesel customers who don’t know the history of their head bolts and fear they have been over tightened and stretched in the past. Some people use a gauge from Precision Measuring Service in Texas to measure the bolt stretch.)

With a clean, straight, correctly finished head now in place and sequentially torqued down, we can focus now on the remaining part of the valve train. Carefully oil the push rods, especially the tips, and insert into the head. Install the rocker arms, ensuring the rocker tips are aligned with the pushrod tips. Then adjust your rocker arms once installed.


Tech Tip #6 Perkins Diesel Engine Maintance Considerations

By larryNo Comments

Tech Tip #3 Maintenance Considerations Perkins Diesels 3.125 and 4.236 Used In Lincoln and Miller Engine Driven welders


Change the fuel and oil filters regularly. In our experience this means at least every 200 hours of industrial use and every 50 hours or at the beginning and in the middle of each season, for marine use. Fuel injectors thrive on clean dry fuel. We strongly recommend that a fuel conditioner be used.

Oil filters aren’t all alike. They vary in price, degree of micron filtration and presence of a check valve to prevent dirty oil from leaving a clogged filter and passing through the engine.

Lubrication Oil

Check the lube oil level at every use and change with the filters. We recommend a blend of synthetic and petroleum based oil, preferably a single SAE weight.

Electrical Systems

Frequently, Perkins users need to upgrade from their standard 45-55 amp alternator to a higher output unit to handle added equipment and larger batteries.  Speaking of batteries, we recommend two deep cycle golf cart batteries for four cylinder marine engines. As a cold start aid, we stock 110 volt block heaters if glow plugs or fuel pre-warmers aren’t sufficient.

The Golden Rules of Diesel Engine Longevity





Tech Tip #2 Continental F-SERIES Ignition Timing

By larryNo Comments

One of the most common questions asked on our help line concerns the ignition timing on Continental engines used on the Lincoln SA-200, SA-250, SA-300, and SA-400 welders.
Since these engines turn no faster than 1800 RPM’s, there is no need for automatic ignition advancement. Over the years we have seen distributors come through our shop with the centrifugal advancement mechanisms rusted into a solid mass of metal, but they run like a top!

Timing is important, but not as important as an engine running at higher speeds. We recommend that the engine be timed, using the vacuum method. This is simple, easy to do, and near fool-proof.On the intake manifold there is a ¼” NPT port right above the carburetor. Remove the pipe plug and attach your vacuum gauge to measure intake manifold vacuum.

Lincoln welder vacuum pressure gauge

With a tachometer measure the engine idle speed, set idle speed for approximately 700 RPM’s. By adjusting the distributor or magneto position the intake manifold vacuum pressure can be optimized. After the maximum vacuum has been achieved, a further increase in manifold vacuum can be achieved by adjusting the “air bleed” screw on the carburetor.
Lincoln welder carburetor m12484 zenith

vacuum pressure gauge

Note the above image shows almost 19 inches of engine vacuum. It cannot be seen in the image, bit the needle did not move!

Vacuum Gauge readings for Continental f-Series Engines (near Sea Level):

  1. 15 to 20 inches of vacuum at idle with very little needle movement means good compression, no valve problems, and no intake manifold leaks
  2. When welder goes from low idle to high idle the vacuum drops to near zero, rising very slowly, but never reaching normal running vacuum-check for worn piston rings and excessive blow by. Time to do a compression check!
  3. A low steady reading of 3 to 6 inches of vacuum-look for a major intake leak. Look for a hole or crack in the intake manifold, defective intake manifold or carburetor gasket.
  4. Idle vacuum seems “normal”, but drops off steadily in a constant manner between low and high idle operations-look for a blown head gasket, with excess smoke, engine overheating.
  5. Needle is steady at idle, then flickers up and down, 3 to 4 pounds regularly. Check for a sticking valve. The “flicker” occurs when the defective valve opens and closes.
  6. Vacuum is steady-near normal at idle, but the needle violently moves 5 to 12″ upon idle up (engine will seem to be struggling to reach weld speed) check the engine for one or more “weak” valve springs.

There are other readings and examples of engine problems that can be identified with a vacuum gauge, but these are the most common.



Tech Tip #1-Distributor installation idea

By larryNo Comments

When we repair or install an upgrade on a customer’s machine we endeavor to make the upgrade as “foolproof” as possible. Case in point: installation of an electronic distributor. The distributor in this case is a Prestolite.


Note the use of silicone to protect the electronic module wires from fraying on the mounting screw (the installation is tight). We apply enough silicone so the wire strain relief to prevent them from being accidentally pulled out-Pertronix is too cheap to make a bigger strain relief!  The Prestolite distributor does not have a rubber gasket; we suggest a thin coat of silicone to be applied to the top rim of the distributor. This should be done as the last step in the installation process.


You need to buy a new Mig-how do you choose the best machine for your purposes?

By larryNo Comments

You want to purchase a new mig machine-what you should look for.

Questions you need to answer:

  1. Will it run on 120 volts or 240 volts? Do you have three-phase power available?
  2. What is the maximum thickness of metal to need to weld in one pass? (You can weld any thickness with multiple passes)
  3. Do you require the ability to weld “thin” metal-20 gauge or less?
  4. The gun that comes with your unit is long enough and does it match the power of the welder?
  5. What is the warranty on the machine?
  6. What is the warranty on the mig gun?
  7. How is the warranty handled and who is responsible?
  8. What if you want to attach a spool gun? What will that cost?


Answers you to have answered:

  1. What is the maximum amperage and duty cycle of your prospective machine?

Duty Cycle refers to the ability of the machine to produce consistent amperage at a set voltage for “X” number of minutes out of a tem minute cycle.

Check out the Millermatic 180 (Stock Number 907312-Price: $1039.00 as of 04/03//11)


It is called a “180” and Miller says it will produce 180 amps at 30% duty cycle.  If you check the specs on the unit at 60% duty cycle the unit is rated at 80 amps!

The unit comes with a M-10 gun-ten feet long. An M-10 gun is rated at 100 amps! Why put a 100 mig gun on a 180 machine? Maybe it’s not really a 180 amp machine? Make you wonder doesn’t it?

Check out the Lincoln PowerMig180C (K2473-1) Price $774.00 (why so much cheaper than the Miller 180?). Check out this link:


Lincoln calls this unit a “180” the literature says it will produce 130 amps at 30% duty cycle. They do not publish a Volt/Amp curve graph in their sales literature so we do not have any idea of how much current it will produce a 60% duty cycle.

  1. How many amps does it take to weld steel plate? This table below will give you a “rule of thumb”-it has worked for me over the years.


18 3/64”— 0.047”- 47 Amps
16 1/16”— 0.062” 62 Amps
14 5/64”— 0.078” 78 Amps
12 1/10”— 0.100” 100 Amps
10 1/8”— 0.0125” 125 Amps
8 5/32” — 0.156” 156 Amps
6 3/16” —0.187” 187 Amps


  1. Can your prospective machine weld 0.025 wire-ask if the 025 feed rolls are available? If you have a strong heart-get a price quote!
  2. The mig gun that comes with your machine; will it handle the maximum amperage that the unit is rated? If not how much more will the proper gun cost you? You must add this cost to purchase of your machine.
  3. Make sure you get a copy of the warranty and READ IT!!!  What is covered and what is not? What does manufacture consider warranty and what does manufacture consider warranty?  Doers you seller provide warranty on site or does the unit have to be “sent-off”. Where does it have to be sent to? What is normal turn around? After the warranty, what is warranty on repair parts? Do they have to be installed by “certified technician” to be warranted?
  4. Ditto on the your mig gun-ask all the questions listed in Line-5.
  5. Find out what spool guns the manufacture carries. Can a aftermarket spool gun be attached? If you purchase their spool gun, will it only work on this machine?


You are going to spend your hard earned money on a machine for your pleasure or profit. Make sure what you are offered is what you will get. If you have any questions please post them on the blog.

Misc Topics on Most Anything

What New Mig Machine-Should I buy?

By larryNo Comments

            Hardly a day goes by that I don’t get a call from someone who has this question-“what mig machine should I buy? My answer is always the same: “I don’t know!” I have been hanging around this industry for almost 40 years-a lot has changed and not for the good!

Beware of anybody who gives you a fast, short, simple answer to a complex question.

Let’s start at the beginning: You want to weld steel with Mig (gas shielded metal arc)? What amperage does you machine need to produce?

The vast majority of welding wire in North America is 0.030 (0.08 mm) and 0.035 (0.09 mm) diameter. If you are into car restoration or wish to do fine Mig welding you need machine that will weld 0.025 (0.06 mm) wire; you can weld sheet metal down to 24 gauge with 025” wire!

You need a machine that will weld all three sizes of wire. How many amps does it take to weld these wires?  This table is a good “rule of thumb”.

0.023 (0.06mm) 30-90 Amps 100-400 IPM
0.030 (0.08 mm) 40-115 Amps 90-340 IPM
0.035 (0.09 mm) 50-180 Amps 80-380 IPM


            What thickness of steel can you weld with mig wire? The table below is a good “rule of thumb” on where to start. Just convert the wire diameter in inches to amps .100” to 100 amps!

No exact-but close enough!

18 3/64”— 0.047”- 47 Amps
16 1/16”— 0.062” 62 Amps
14 5/64”— 0.078” 78 Amps
12 1/10”— 0.100” 100 Amps
10 1/8”— 0.0125” 125 Amps
8 5/32” — 0.156” 156 Amps
6 3/16” —0.187” 187 Amps


In the next blog we will discuss what you should look for a mig machine.

Misc Topics on Most Anything

Tech Tip #3 Fiber Gear Timing Fairbanks Morse FMX4B16 Magneto

By larryNo Comments

We get calls from frustrated welders and mechanics all the time about timing the fiber gear and steel gear inside the Fairbanks-Morse magneto.  It is much easier to R & R the points/condensor if you remove the fiber gear (and zero chance of slipping and breaking it!)  The attached image shows the timing marks and how to count the teeth if the C & A is missing off your fiber gear. FYI the fiber gear P/N: Y5939, the mating steel gear is P/N: Q5952

fairbanks morse q5952 steel gear fmx4b16 magneto y5989

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