Husqvarna 346 Won’t Start Hot (Causes & Fixes)
If your Husqvarna 346 starts cold but will not restart hot, do not keep pulling with the choke on. Set the saw safely, use its warm-start method, then check whether the spark plug is wet or dry. That quick clue helps separate flooding from fuel-flow problems. If spark or compression changes when hot, stop guessing and test those systems.
Warm weather can make a hot-start problem show up sooner, especially after a long cut and a brief stop. But temperature alone does not identify the fault. A wet plug, a dry plug, or spark that disappears when the saw is hot points you toward different checks.
I diagnose this in a set order because replacing a carburetor or ignition module without testing can waste money. First confirm the warm-start method, then inspect the plug and test fuel and spark. If those checks do not explain it, investigate compression and air leaks.
Equipment setup and safety prep
A hot-start check needs a safe, repeatable setup. Start outdoors, away from flames or sparks, and keep the bar and chain clear of people and objects. Use the operator’s manual for your exact 346 version; carburetors and procedures can differ across models and markets.
Wear eye and hearing protection, gloves, boots, and chainsaw-rated leg protection. Engage the chain brake, place the saw on firm ground, and follow the manual’s starting position. Do not drop-start it. Check that the throttle interlock works, the stop switch is set to run, and there are no visible fuel leaks.
Identify the exact model before ordering parts or applying settings. The 346XP has 50.1 cc displacement, but that does not mean every 346-family saw shares the same carburetor or service settings. Check the model plate and serial information, then use the matching operator’s or service manual.
Fuel matters, too. With Husqvarna two-stroke oil, the specified mix is 50:1 by volume: 20 mL of oil per 1 L of gasoline. If you use another approved oil, follow its instructions and the saw manual. Never use straight gasoline or an unknown, stale mix.
Restart the saw correctly while hot
A warm-start procedure avoids adding more fuel to an engine that may already be flooded. Set the saw down as directed in its manual, engage the chain brake, and use the warm-start method for that carburetor version. A warm engine normally needs no choke; check the manual if the controls differ.
Pull the starter until the engine fires. Once it runs, let the throttle return to idle before releasing the chain brake. If the saw does not start after a few proper attempts, stop and inspect rather than repeating choke pulls.
Read the spark plug before changing parts
The spark plug gives a useful first clue. Stop the saw, move it away from ignition sources, and let it cool before removing the plug. Disable the ignition as described in the manual. Do not inspect or dry a plug beside spilled fuel or while the engine is hot.
| What you find | What it suggests | Next check |
|---|---|---|
| Wet plug or strong fuel smell | Possible flooding or weak/no ignition | Use the manual’s clear-flood method; then test spark |
| Dry plug after repeated pulls | Fuel may not be reaching the cylinder | Check fuel condition, filter, line, tank vent, and carburetor |
| Plug looks normal, but no hot restart | Fault may appear only at operating temperature | Test hot spark, then assess compression and sealing |
A wet plug does not prove the carburetor is faulty. It shows fuel reached the cylinder, but the mixture may be too rich or the spark may be absent. A dry plug points toward delivery, but it is not proof by itself.
Common reasons a 346 will not restart hot
Several faults can look alike at the starter cord. Use the clues below to choose the next test. Do not turn the carburetor screws at random; an incorrect adjustment can hide a fault or create a dangerously lean condition.
Flooding from choke or restart technique
Flooding means excess fuel has made the air-fuel mix too rich to ignite. It often happens when the choke is used on a warm engine or the operator keeps pulling with the choke on. A wet, fuel-smelling plug supports this diagnosis.
Follow the manual’s clear-flood procedure. Typically, that means choke off and the throttle fully open as directed while pulling the starter. Avoid more choke pulls. If needed, remove and dry or replace the plug only after the engine is cool and ignition is disabled. Use the correct plug and check the specified gap for your exact version; applicable 346XP versions use 0.5 mm (0.020 in.).
If flooding keeps returning despite correct starting technique, inspect the carburetor and its metering system. A metering diaphragm controls fuel flow inside the carburetor; age or damage can affect how it responds. Have the carburetor checked rather than compensating with guessed screw settings.
Fuel delivery that changes as the saw heats
A dry plug suggests checking the fuel path. Confirm the fuel is fresh and correctly mixed. Then inspect the tank vent, fuel filter, and pickup line for blockage, damage, or a loose connection. A blocked vent can prevent fuel from flowing as the tank empties.
A carburetor diaphragm can also lose its ability to meter fuel as it should. Heat-related vapor or fuel-delivery problems are possible, but test the simple items first. If the plug stays dry and the lines and vent appear clear, the carburetor needs a proper inspection.
Ignition that fails only when hot
A failing ignition component may work cold and stop producing spark after heating. The stop-switch wire or ignition module/coil should be checked when the fault is present, not only after the saw cools.
Use a suitable spark tester and follow the tool instructions. Keep the test away from fuel and spilled gas. A visible spark when cold does not rule out a hot failure. If spark disappears hot and returns after cooling, have the switch wiring and ignition module tested against the correct service information before buying parts.
Low hot compression or an air leak
Compression is the pressure created in the cylinder as the piston moves. If the saw starts cold but has trouble hot, cylinder, piston, or sealing problems may need assessment. A compression test is only useful when done with the right procedure and compared with the service guidance for that exact saw.
Do not rely on a made-up pressure threshold. If fuel and hot spark are present but the saw still will not restart, ask a qualified technician to assess hot compression, piston and cylinder condition, and crankcase sealing. A leak can also make the engine run lean.
Diagnostic examples and next steps
These are common diagnostic patterns, not proof that every saw with the same symptom has the same failed part. I use them to show how one observation narrows the next test without replacing parts by guesswork.
| Situation | Best next step | Avoid |
|---|---|---|
| It ran well, then will not start after a short warm stop; plug is wet | Clear flooding with choke off, then test spark if it still will not fire | Repeated pulls with choke on |
| It quits during a cut and the plug is dry | Check fuel mix, tank vent, filter, and line | Assuming the carburetor is the only cause |
| It restarts after cooling but has no spark while hot | Test ignition and stop-switch wiring when hot | Buying a coil based only on the symptom |
| It surges, races at idle, or loses power under load | Stop running it and check for fuel restriction or an air leak | Continuing to cut or richening the carb by ear |
The last pattern is urgent. A blocked vent, restricted filter or line, air leak, or failing diaphragm can cause a lean mixture. A lean-running saw can overheat and score the piston and cylinder. Stop if it races at idle, surges, loses power, or will not idle reliably. Repair the cause and verify carburetor settings with a tachometer and leak testing, not by ear alone.
After the hot-start fault is fixed
Before cutting, confirm the engine idles steadily, accelerates cleanly, and stops the chain at idle. Check chain lubrication and brake operation. The idle speed is approximately 2,700 rpm for applicable versions, but use the specification for your exact saw and verify it with a tachometer.
Bar and chain fit must also be correct. Match pitch, gauge, drive-link count, and sprocket; read the bar stamp and count the links rather than assuming a fit. A 13–18 inch bar is a practical general-purpose range for a healthy, correctly configured 346, but do not exceed the bar length approved in the manual.
Shut the saw down before adjustments or transport. Let it cool before refueling, cleaning, or inspecting the plug. Keep up with filter and fuel-system checks, and store fuel in a labeled container. If you are doing tree work, follow applicable ANSI Z133 and OSHA requirements. Do not fell trees without suitable training and a planned escape route.
FAQs about a Husqvarna 346 that will not start hot
These quick answers help you choose the next safe check. They do not replace the manual for your saw’s exact model and carburetor. If a test points to internal engine damage or a fuel-system leak, stop running the saw until it is checked.
Should I use the choke to restart a warm 346?
Normally, no. A warm engine generally uses the no-choke warm-start procedure, but follow the manual for your exact carburetor version. Repeated choke pulls can flood it.
What does a wet spark plug mean?
A wet or fuel-smelling plug suggests fuel is reaching the cylinder. The engine may be flooded, or the ignition may not be lighting the mixture. Test rather than assuming the carburetor has failed.
What if the plug is dry?
Check fuel age and mix, then inspect the tank vent, filter, and pickup line. If those are clear, have the carburetor and metering diaphragm examined.
Why does the saw start again after it cools?
A heat-sensitive ignition fault is one possibility. Test for spark while the fault is present. Fuel delivery, compression, and sealing issues can also need checking.
Can I turn the carburetor screws to fix hot starting?
Do not adjust them at random. Incorrect settings can cause poor running or a lean condition that may damage the engine. Use the exact service procedure, a tachometer, and leak testing where required.
What fuel mix should I use?
For Husqvarna two-stroke oil, use 50:1: 20 mL oil per 1 L of gasoline. Follow the manual if using another approved oil. Do not use straight gas or stale, unlabeled premix.
What spark-plug gap should I set?
Applicable 346XP versions specify 0.5 mm (0.020 in.). Confirm the plug type and gap in the manual for your exact model before adjusting it.
When should I stop troubleshooting and get service?
Stop if the saw races at idle, surges, loses power, has no spark hot, or has fuel leaks. If fuel and spark checks do not explain the problem, have hot compression, the piston and cylinder, and crankcase sealing assessed.
(This article was written by one of our staff writers, Robert Callahan. Visit our Meet the Team page.)
