Question about Stihl TS420

1 Answer

Why Do I Not Have Any Spark From The Ignition Module When Spark Plug is in The Cylinder

I have spark to plug and spark tester when turning saw when spinning it over w a drill and socket with plug out of cylinder, but none with plug screwed in cylinder! Saw turns over faster w plug out. I set the air gap w business card, checked it w feeler gauge was .008? Is that correct? Just rebuilt saw w new cyl., piston and rings, carb, and decomp valve. The orig ign module had no fire, replaced w aftermarket? Oem stihl is $175! Any help or tips will be appreciated. Is cutomers and have $400 in parts not countin labor and will not start. Thank You

Posted by Rocky Harris on


1 Answer

Claude Kayser

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.


    An expert that got 20 achievements.


    An expert that got 10 achievements.

  • Stihl Master
  • 9,098 Answers

Search Results

    Stihl TS400 / TS420 Ignition Module Repair - YouTube

    ? 7:06
    May 1, 2011 - Uploaded by donyboy73
    Learn HOW TO REPLACE The Ignition Module in your StihlTS400 / TS420 ... I have a homelite 33cc Ranger it has no sparkat the plug but if I put a ... a good spark and there is fuel getting into the cylinder head also what are ...

    All comments on Stihl TS400 / TS420 Ignition Module Repair
    Donyboy73, I hava a Stihl TS 420 and just replaced the pull rope (not sure what's ... a good spark and there is fuel getting into the cylinder head also what are your ..... Hi mate, i have no spark to my plug?? i have tried a brand new plug and still ...

    Small Engine Ignition: Ignition Wires, Chainsaw Spark Plugs ...
    66 results - HL Supply has the small engine ignition parts that will get your ... parts right here: ignition wires, chainsaw spark plugs, ignition coil sets, ... Please don't hesitate to contact us if you have any questions. ... Stihl TS400 (3-bolt old style), TS460 ignition coil with wire and cap ... Fits: Stihl TS410 and TS420 cut off saws

Posted on Feb 08, 2016


Add Your Answer


Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Intermittent and weak spark

Is the new ignition module gapped right? Are you using a spark tester or just trying to hold it to the cylinder while pulling the rope? If the module sparks then it most likely is not a spark issue. Make sure you have fuel to the cylinder and that the compression in the saw is good. The easiest way to test a fuel delivery issue is to pour a Small amount of fuel right in to the carburetor and try to start it. It should run on the fuel you put in then die if it has a fuel issue.

If you need further help, I’m available over the phone at

Dec 17, 2013 | Husqvarna Garden

1 Answer

Is there a way to test the spark module before buying a new one darn things are expensive

Sorry but the only true way is to put the unit on the machine, set the air gap to 0.3mm diss connect any wires on the unit that go to the switch, assemble the starter, use a new plug or spark tester with a wide gap, earth well against the cylinder, crank the engine as if you were going to start it, if there is a spark the unit is ok, if not then its bad. There are expensive testers on the market, but if the unit does not spark on the saw what is the point of testing it.

Feb 02, 2013 | Husqvarna , No.455 Rancher, 20" Gas -...

1 Answer

Stihl 066 does not start. Replaced ignition module. Weak or no spark.

Are the poles on your flywheel blue? Are you using an open-air inline spark tester, or holding the plug against the cylinder and turning it over?

Jul 14, 2012 | Stihl Chainsaw 051 075 076 Drum Chain Saw...

1 Answer


The only true way to check the ignition is to leave it connected to the saw, remove the plug, useing a suniversal spark tester, crank the engine over with the starter, if you do not have a spark tester, place a new plug against the top of the cyliner insuring the plug body is well earted against the cylinder ( keep it away from the open spark plug hole ) crank the engine, if it has a spark you have to assume it is ok, it is very difficult to diagnose a unit that breaks down when it is hot, you would have to fit a known good unit to the sawand try.

Aug 24, 2011 | Poulan Garden

1 Answer

How to check spark on a wildthing?

Remove the top cover, remove the spark plug, if you have a spark tester conect it to the ht leed, if not connect the spark plug back to the cap, rest it on top of the cylinder, make sure it is away from the spark plug hole, switch the ignition switch on, crank the engine as if starting, there should be a reasonable spark at the plug,

Apr 27, 2011 | Poulan Wild Thing 2375 18" Gas Chain Saw...

1 Answer

How do i do compression test on 2006 yzf 450 f

Remove spark plugs. Insert compression tester pressure pipe against each plug hole in turn. Spin the engine for 15 seconds whilst holding the pressure tester in each plug hole. No throttle. The readings should be the same from each cylinder or at least within 1 or 2%.

Jan 12, 2011 | 2004 Yamaha YZ 450 F

1 Answer

How to get the clutch off on a 142 husky

  1. Turn off the saw and release the chain brake. The chain brake is the plastic handle located on the topside of the saw's body, and is between the bar and the throttle. With a gloved hand, spin the chain to ensure the brake is off.
  2. Use the wrench to loosen the bar nuts until they are finger tight. Use the flathead screwdriver to loosen the bar tensioner screw. This screw is located in between the bar cover's two metal posts, and can be reached through the small, round hole in the cover's center.
  3. Finish loosening the bar nuts and remove the bar cover. Take off the bar and chain; set them aside in a safe place.
  4. Unplug the spark plug from the rubber spark plug connector, located on the top of the saw's body. Push some of the chainsaw's starter chord string into the spark plug cylinder to block the piston from moving while taking apart the clutch.
  5. Remove the clutch assembly with the clutch socket wrench. Husqvarna chainsaw clutches are left-locking nuts, so you will need to turn the bolt clockwise to loosen it. Tap on the socket's handle with a hammer if the bolt won't loosen.
  6. Remove the bolt and pull off the clutch cover, clutch spring and clutch drum. Replace these parts if they are chipped, warped or heavily worn.
  7. Follow these steps in reverse order to reassemble the clutch.

Nov 15, 2010 | Husqvarna "Chain Saw - 16" Bar, 3 Hp

1 Answer

Changed fuel pump. getting fuel to engine. but will not start.

Check for spark. Maybe a crankshaft position sensor is bad or a module.

Secondary Spark Test This spark tester looks just like a spark plug, attach the clip to ground and crank the engine to check for spark 91052p10.jpg
This spark tester has an adjustable air-gap for measuring spark strength and testing different voltage ignition systems 91052p11.jpg
Attach the clip to ground and crank the engine to check for spark 91052p12.jpg
This spark tester is the easiest to use just place it on a plug wire and the spark voltage is detected and the bulb on the top will flash with each pulse 91052p10.jpg
The best way to perform this procedure is to use a spark tester (available at most automotive parts stores). Three types of spark testers are commonly available. The Neon Bulb type is connected to the spark plug wire and flashes with each ignition pulse. The Air Gap type must be adjusted to the individual spark plug gap specified for the engine. The last type of spark plug tester looks like a spark plug with a grounding clip on the side, but there is no side electrode for the spark to jump to. The last two types of testers allows the user to not only detect the presence of spark, but also the intensity (orange/yellow is weak, blue is strong).
  1. Disconnect a spark plug wire at the spark plug end.
  2. Connect the plug wire to the spark tester and ground the tester to an appropriate location on the engine.
  3. Crank the engine and check for spark at the tester.
  4. If spark exists at the tester, the ignition system is functioning properly.
  5. If spark does not exist at the spark plug wire, perform diagnosis of the ignition system using individual component diagnosis procedures.
Ignition Coil Testing
  1. Remove suspect coil.
  2. Disable fuel pump by disconnecting inertia switch electrical connector.
  3. Reconnect the ignition coil electrical connector to the coil.
  4. Install spark tester 303-D307 (D81P-6666-A) or the equivalent.
  5. Crank engine while observing the tester.
  6. If a blue-white spark is not observed replace coil.
Removal & Installation To Remove:
  1. Remove the air cleaner outlet pipe if interfering.
  2. Disconnect the connector from the ignition coil. coilconn.gif

  3. Remove the bolt from the ignition coil. coilbolt.gif

  4. Remove the ignition coil on plug.
To Install:
  1. Install ignition coil on spark plug.
  2. Install ignition coil bolt. Tighten to 10 Nm (89 in. lbs.). coilbolt.gif

  3. Reconnect the ignition coil electrical connector. coilbolt.gif

  4. Install the air cleaner outlet pipe if removed earlier.
prev.gif next.gif

Oct 28, 2010 | 1999 Ford Crown Victoria

Not finding what you are looking for?
Stihl TS420 Logo

741 people viewed this question

Ask a Question

Usually answered in minutes!

Top Stihl Garden Experts

ray gallant

Level 3 Expert

71004 Answers

Thomas Perkins
Thomas Perkins

Level 3 Expert

14852 Answers

bryan st

Level 2 Expert

123 Answers

Are you a Stihl Garden Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides