Partner P740 Chainsaw Won’t Start (Troubleshooting)
A Partner P740 that will not start needs a step-by-step check, not a pile of replacement parts. Confirm the saw’s exact variant and safe starting procedure first. Then check the switch, fuel, spark plug, air intake, and compression in order. A wet or dry plug helps narrow the fault, but does not prove it alone.
If you have already pulled the starter cord again and again, pause. More pulls can flood the engine or hide the original clue. I work through no-start problems by changing one thing at a time and checking what the saw tells us. That saves money and avoids guessing at parts or carburetor settings.
Set up safely and confirm your P740 variant
The Partner P740 is an older two-stroke chainsaw, and details can vary by model year or market. Before starting or ordering parts, read the model and serial information on the saw, then find the matching operator’s manual. Do not assume a fuel ratio, plug, carburetor setting, bar, or chain specification from the model name alone.
Start with the saw on firm ground, with the bar clear of people and objects. Wear eye, hearing, hand, leg, and foot protection. Engage the chain brake, hold the saw securely as the manual directs, and do not drop-start it.
Before operation or adjustment, verify these details:
- Fuel ratio and two-stroke oil type specified for your exact P740.
- Spark plug type and gap specified in its manual.
- Carburetor settings and idle speed from the correct service information.
- Chain pitch, gauge, and drive-link count against the bar stamp and drive sprocket.
- Bar-and-chain oil type and the manual’s oil-delivery test.
If you cannot confirm the fuel ratio, do not run the saw. Never use straight gasoline or an unverified fuel mix. Use suitable chainsaw bar-and-chain lubricant, not engine oil, and do not run the chain dry.
Check the controls and use the correct starting procedure
Starting controls are the first checks because a stop switch in the wrong position or an incorrect choke sequence can look like an engine fault. The P740’s exact control sequence depends on its version. Use the matching manual; if you cannot confirm the steps, avoid repeated guesses.
Before another attempt, inspect for fuel leaks, damaged fuel lines, a loose or cracked fuel cap, a blocked air filter, and a loose spark-plug cap. Check that the stop switch is set to RUN and that the controls move freely. Do not bypass the chain brake, throttle interlock, or other safety devices.
Follow the manual’s cold-start or warm-start sequence exactly. If the saw does not fire, do not keep pulling without checking for flooding. A flooded engine has too much fuel in the cylinder to ignite well. A wet spark plug is a useful clue, though it does not prove flooding is the only fault.
- If the plug is wet, follow the manual’s clear-flood procedure.
- If you do not know the procedure, stop and get the correct manual rather than holding the throttle or changing control positions at random.
- If the plug is dry after correct starting attempts, fuel may not be reaching the cylinder.
Read the spark plug, fuel, and ignition clues
Fuel and ignition checks help separate a simple starting problem from a fault that needs testing. A plug’s condition after a correct start attempt can guide the next step, but no single sign confirms a failed part. Use the specified plug and the model-specific service information.
First, drain stale or unknown premix into an approved container. Refill with fresh fuel mixed at the ratio specified for this P740 variant. Do not use a generic 50:1 mix unless the correct manual calls for it. Old or incorrect fuel can prevent starting and may damage the engine.
Remove and inspect the spark plug only when the saw is cool and the ignition lead is disconnected. Look for a wet, fouled, damaged, or heavily worn plug. Check its gap against the manual, not a general chart. Replace it only with the specified type.
| What you find | What it may indicate | Next step |
|---|---|---|
| Plug is wet after repeated attempts | Flooding, weak spark, or poor combustion | Use the manual’s clear-flood steps; inspect the plug and ignition |
| Plug is dry after correct attempts | Fuel may not be reaching the cylinder | Check fuel freshness and then have fuel delivery tested |
| Plug is fouled or damaged | Plug may not spark reliably | Fit the specified plug and gap, then retry correctly |
| No reliable spark on a proper tester | Ignition fault is possible | Have the switch, lead, coil, and related parts tested |
| Fuel leak or damaged line | Unsafe condition and possible supply fault | Do not start; repair before testing |
A spark test must be done with an appropriate tester and a safe procedure. Keep fuel away from sparks and hot surfaces. If you do not have the right tool or instructions, leave ignition testing to a qualified technician. A visible spark alone does not prove it is strong enough under compression.
I use the plug as a direction marker, not a verdict. In a common diagnostic pattern, a dry plug after correct starting attempts sends the check toward the fuel filter, lines, carburetor, or impulse passage. A wet plug sends it toward flooding, spark quality, or combustion. Neither pattern justifies buying a carburetor or coil without further testing.
Check air intake, compression, and likely fault patterns
Air is part of the fuel-air mix the engine needs to run. A blocked filter can restrict airflow, while low compression can prevent the engine from firing. These checks come after the safe starting, fuel, and plug checks because they require more care and, in some cases, test equipment.
Remove and inspect the air filter as the manual directs. Clean or replace it using the approved method; do not run the saw with the filter removed as a shortcut. Also inspect cooling-air passages for packed dirt, since blocked cooling can lead to overheating if the saw does start.
A dry plug points toward fuel delivery, but the cause may be a blocked filter, damaged line, carburetor problem, or blocked impulse passage. A wet plug may mean flooding, weak ignition, or poor combustion. If fresh, correctly mixed fuel and a sound plug do not solve the problem, testing is more useful than replacing parts.
| Symptom or test result | Likely area to investigate | Do not assume |
|---|---|---|
| Engine does not respond; switch was at STOP | Control position | That the ignition coil has failed |
| Dry plug after correct procedure | Fuel delivery | That the carburetor alone is at fault |
| Wet plug and no start | Flooding, ignition, or combustion | That a new plug will fix every cause |
| Starter pulls unusually easily | Compression or internal wear may need checking | A specific compression value without service data |
| Starter cord will not pull normally | Starter, engine, or another mechanical issue | That harder pulling is safe |
Compression is the pressure made in the cylinder as the piston moves. A compression gauge and the correct service data help assess it; do not rely on a generic pressure threshold for an unidentified P740 variant. Low compression, suspected crank-seal or cylinder trouble, or a starter that is damaged or binds calls for proper inspection. Do not keep pulling hard.
When to stop and get testing
Some checks need a spark tester, compression gauge, or model-specific service data. If you cannot test safely, stop before adjusting the carburetor or opening the engine. A technician can test the ignition, fuel lines, filter, carburetor, impulse passage, and compression rather than swapping parts at random.
Do not tune carburetor screws by ear, use generic H/L screw turns, or defeat limiter caps. An excessively lean setting can overheat the engine and damage the piston or cylinder. Use the correct service data and a tachometer if tuning is permitted for your model.
Stop using the saw immediately if it races, stalls, loses power, overheats, or behaves abnormally. Stale fuel, an incorrect oil ratio, air leaks, or restricted fuel flow can create a lean-running condition and risk a piston-and-cylinder seizure. Do not “test it” by continuing to cut.
After repair, do not put the saw back to work until it starts reliably, idles without chain movement, accelerates cleanly, stops with the switch, and oils the chain. Confirm brake operation, throttle interlock, chain catcher, chain tension, and correct bar-and-chain fit before cutting.
Prevent the next no-start
Storage and basic care help avoid stale-fuel and blocked-part problems. Follow the P740 manual’s fuel-storage instructions: it may call for draining and running the carburetor dry, or for an approved stabilizer and storage procedure. Do not leave unknown or stale premix in the saw.
Keep the air filter and cooling passages clean. Inspect the fuel filter, lines, plug, starter, bar groove, oil holes, sprocket, and chain for wear or damage. Use the chain maker’s file size, sharpening angles, and depth-gauge instructions; do not guess a generic raker setting.
Before storage, clean the saw, manage bar oil as the manual directs, protect the bar and chain, and store it dry and away from children. The chain should be guarded, and the machine should be stored in a safe condition according to its manual.
FAQ: Partner P740 starting problems
These answers cover the most common next steps after a P740 fails to start. Use the manual for your exact saw before changing settings or parts. If a check requires tools or service data you do not have, stop rather than guessing.
Why will my Partner P740 not start?
Common causes include an incorrect starting sequence, stale or incorrect fuel mix, a flooded or fouled plug, restricted fuel delivery, weak ignition, or low compression. Check the controls and plug condition first, then test one system at a time.
What fuel ratio does a Partner P740 use?
Use the ratio and two-stroke oil specified in the manual for your exact model and market version. Do not assume 50:1, and do not run the saw if you cannot verify the required mix.
What does a wet spark plug mean?
A wet plug can point to flooding, but weak ignition or poor combustion can also leave it wet. Follow the manual’s clear-flood procedure, then inspect the plug and check ignition safely.
What does a dry spark plug mean?
A dry plug after correct starting attempts suggests fuel may not be reaching the cylinder. Check fuel freshness, then have the filter, lines, carburetor, and impulse passage tested if the problem remains.
Should I adjust the carburetor screws?
Not without the correct P740 service data and the right tools. Generic screw settings or tuning by ear can make the mixture too lean and damage the engine.
Can I keep pulling the starter cord?
No. Stop after checking that you followed the correct starting procedure. Repeated attempts can flood the engine, and forcing a starter that binds can cause damage.
When should I stop troubleshooting at home?
Stop if there is a fuel leak, no reliable spark, a damaged starter, suspected low compression, or possible cylinder or crank-seal trouble. These faults need proper testing and repair.
What must work before I cut with the saw?
It must start reliably, idle without chain movement, accelerate cleanly, stop with the switch, and oil the chain. Also confirm the brake, interlock, chain catcher, chain tension, and approved bar-and-chain setup.
(This article was written by one of our staff writers, Robert Callahan. Visit our Meet the Team page.)
