feat: Add OverheatStalling issue - carburetor tuning problem
- Documented issue: runs 5 min, stalls when warm, won't restart until cooled - Suspected cause: carburetor running too rich when hot - Added factory settings reset procedure (L: 1.5 turns, H: 1.25 turns as starting point) - Included adjustment procedure for fine-tuning leaner - Tools needed: spline carb adjustment tool (John has this) - Parts to check: air filter, spark arrestor, fuel filter - Links to written guides and videos - Success criteria: 10+ min run time without stalling, immediate restart after warm stall
This commit is contained in:
John Loper II
@@ -0,0 +1,253 @@
|
||||
# Issue: Chainsaw Stalls When Warm - Carburetor Tuning Issue
|
||||
|
||||
> **See main overview:** [README.md](../README.md)
|
||||
|
||||
---
|
||||
|
||||
## 📋 Quick Summary
|
||||
|
||||
**Issue:** Chainsaw runs ~5 minutes, then stalls when warm; won't restart until cooled down (1+ hour)
|
||||
**Date Reported:** 2026-03-22
|
||||
**Saw Model:** Husqvarna 440 CH (X-TORQ)
|
||||
**Severity:** Medium - Saw unusable for extended work
|
||||
**Status:** 🔍 INVESTIGATION - Likely carburetor tuning issue
|
||||
|
||||
---
|
||||
|
||||
## 🪵 Chainsaw Details
|
||||
|
||||
- **Year/Make/Model:** Husqvarna 440 CH (X-TORQ)
|
||||
- **Engine:** 50.9cc 2-cycle single cylinder
|
||||
- **Serial Number:** TBD
|
||||
- **Current Hours:** TBD
|
||||
|
||||
---
|
||||
|
||||
## 🔍 Problem Description
|
||||
|
||||
**Symptoms:**
|
||||
- ✅ Saw starts cold and runs fine
|
||||
- ✅ Runs for approximately 5 minutes
|
||||
- ❌ **Stalls when engine gets warm**
|
||||
- ❌ **Won't restart until cooled down** (1+ hour cooling period)
|
||||
- ✅ Starts again after cooling, cycles repeat
|
||||
|
||||
**When it Occurred:**
|
||||
- [Date/time - when did this start?]
|
||||
- [Any recent maintenance or carburetor changes?]
|
||||
- [Fuel condition - fresh or old?]
|
||||
|
||||
**Suspected Cause:**
|
||||
- **Carburetor tuning** - Classic cold-run rich / hot-run lean symptom
|
||||
- When cold: needs richer mixture (correct)
|
||||
- When warm: needs leaner mixture (incorrect - running too rich when hot)
|
||||
- **Fuel vapor lock** or **hot idle mixture too rich**
|
||||
|
||||
---
|
||||
|
||||
## 📊 Diagnostic Findings
|
||||
|
||||
### Current Status
|
||||
**NOT YET TESTED** - Need to perform carburetor adjustment
|
||||
|
||||
### What Has Been Verified
|
||||
- [x] **Properly lubricated** - Chain and bar well-oiled
|
||||
- [x] **Proper fuel mix** - 50:1 ratio with quality 2-cycle oil
|
||||
- [ ] **Carburetor adjustment checked** - TBD
|
||||
- [ ] **Air filter cleaned** - TBD
|
||||
- [ ] **Spark arrestor screen checked** - TBD
|
||||
- [ ] **Spark plug condition** - TBD
|
||||
- [ ] **Fuel filter checked** - TBD
|
||||
|
||||
---
|
||||
|
||||
## 🎯 Theories & Root Cause Analysis
|
||||
|
||||
### Most Likely Causes (ranked by probability)
|
||||
|
||||
1. **Carburetor Mixture Too Rich (Hot)**
|
||||
- **Why:** Classic symptom of rich mixture - runs fine cold, dies when warm
|
||||
- **Evidence:** Runs 5 min then stalls; won't restart until cool
|
||||
- **How to confirm:** Reset to factory settings, adjust L and H screws leaner
|
||||
- **Fix:** Lean out L screw slightly, adjust H screw
|
||||
|
||||
2. **Fuel Vapor Lock**
|
||||
- **Why:** Fuel vaporizes in carburetor when hot, causing lean condition
|
||||
- **Evidence:** Runs cold, stalls when hot, restarts when cool
|
||||
- **How to confirm:** Check fuel flow when hot, inspect fuel lines
|
||||
- **Fix:** Adjust carb, check for fuel restriction, ensure proper ventilation
|
||||
|
||||
3. **Spark Arrestor Clogged**
|
||||
- **Why:** Restricts exhaust flow when engine gets hot
|
||||
- **Evidence:** Loss of power when hot, stalling
|
||||
- **How to confirm:** Remove and inspect spark arrestor screen
|
||||
- **Fix:** Clean or replace spark arrestor
|
||||
|
||||
4. **Air Filter Restriction**
|
||||
- **Why:** Dirty air filter causes rich mixture, worse when hot
|
||||
- **Evidence:** Reduced performance, especially when warm
|
||||
- **How to confirm:** Remove and inspect air filter
|
||||
- **Fix:** Clean or replace air filter
|
||||
|
||||
5. **Carburetor Diaphragm Issues**
|
||||
- **Why:** Worn or stuck diaphragms cause incorrect fuel metering
|
||||
- **Evidence:** Running issues that change with temperature
|
||||
- **How to confirm:** Inspect carburetor diaphragms
|
||||
- **Fix:** Rebuild or replace carburetor
|
||||
|
||||
---
|
||||
|
||||
## 🔧 Tools Needed
|
||||
|
||||
### Required Tools
|
||||
- [ ] **Spline carburetor adjustment tool** - (John has this!)
|
||||
- [ ] Spark plug socket (21mm)
|
||||
- [ ] Screwdriver set (small flathead for T screw)
|
||||
- [ ] Multimeter (optional, for spark plug check)
|
||||
- [ ] Tachometer (optional, for precise RPM adjustment)
|
||||
|
||||
### Safety Equipment
|
||||
- [ ] Safety glasses
|
||||
- [ ] Chainsaw gloves
|
||||
- [ ] Hearing protection
|
||||
|
||||
---
|
||||
|
||||
## 📦 Parts & Materials
|
||||
|
||||
### Parts to Consider (if needed)
|
||||
| Part | Part Number | Cost | Status |
|
||||
|------|-------------|------|--------|
|
||||
| Air Filter | 531 30 69-01 | $10-15 | 🔍 Check first |
|
||||
| Spark Arrestor Screen | 574 76 39-01 | $15-25 | 🔍 Check first |
|
||||
| Fuel Filter | 504 30 43-01 | $5-10 | 🔍 Check first |
|
||||
| Carburetor Rebuild Kit | 530 04 28-01 | $25-40 | Last resort |
|
||||
| Complete Carburetor | 530 04 28-02 | $80-120 | Last resort |
|
||||
|
||||
### Materials
|
||||
- [ ] Carburetor cleaner
|
||||
- [ ] Compressed air
|
||||
- [ ] Clean rags
|
||||
- [ ] Fresh fuel mix (50:1)
|
||||
- [ ] Dielectric grease
|
||||
|
||||
---
|
||||
|
||||
## 📚 Resources
|
||||
|
||||
### Written Guides
|
||||
- 📖 **Factory Carb Settings:** https://axeandanswered.com/factory-carb-settings-for-husqvarna-chainsaw/
|
||||
- 📖 **Husqvarna 440 Adjustment:** https://mygardenplans.com/how-to-adjust-husqvarna-440-chainsaw-carburetor/
|
||||
- 📖 **Engineer Fix Guide:** https://engineerfix.com/how-to-adjust-the-carburetor-on-a-husqvarna-440/
|
||||
|
||||
### Video Resources
|
||||
- 📺 [YouTube: Husqvarna 440 carburetor adjustment](https://www.youtube.com/watch?v=m2tuwRoaAdU)
|
||||
- 📺 [YouTube: Husqvarna 440 carburetor repair](https://www.youtube.com/watch?v=anP6UlOMN4Y)
|
||||
- 📺 [YouTube: General Husqvarna carb adjustment](https://www.youtube.com/watch?v=Jq3P6qjaKJ0)
|
||||
|
||||
---
|
||||
|
||||
## 🔧 Adjustment Procedure (Recommended Starting Point)
|
||||
|
||||
### Step 1: Reset to Factory Settings
|
||||
|
||||
**Current suspected issue:** Running too rich when hot
|
||||
|
||||
**Factory default settings:**
|
||||
- **L Screw:** 1¼ - 2¼ turns out from fully seated
|
||||
- **H Screw:** 1¼ - 1½ turns out from fully seated
|
||||
- **T Screw:** Adjust for smooth idle, chain should NOT rotate
|
||||
|
||||
**Recommended starting point for your issue:**
|
||||
1. **Turn L clockwise until lightly seated** (do not overtighten)
|
||||
2. **Back L out to 1½ turns** (middle of range)
|
||||
3. **Turn H clockwise until lightly seated** (do not overtighten)
|
||||
4. **Back H out to 1¼ turns** (slightly leaner side of range)
|
||||
5. **Start saw and let warm up**
|
||||
|
||||
### Step 2: Fine Adjustment (After Warm Up)
|
||||
|
||||
1. **Run saw for 5 minutes** until it starts to struggle
|
||||
2. **Turn L screw 1/8 turn COUNTER-CLOCKWISE** (leaner)
|
||||
3. **Test run** - see if it still stalls
|
||||
4. **If still stalling:** Turn H screw 1/8 turn COUNTER-CLOCKWISE (leaner)
|
||||
5. **Repeat** until saw runs smoothly for 10+ minutes
|
||||
|
||||
**Important:** Make small adjustments (1/8 turn), let saw stabilize 30 seconds between adjustments.
|
||||
|
||||
### Step 3: Verify Performance
|
||||
|
||||
1. **Run saw for 10+ minutes** continuously
|
||||
2. **Test throttle response** from idle to full throttle
|
||||
3. **Check idle** - chain should NOT rotate
|
||||
4. **Test restart after stall** - should restart without cooling
|
||||
|
||||
---
|
||||
|
||||
## 📋 Next Steps
|
||||
|
||||
- [ ] **Reset carburetor to factory settings** (L: 1½ turns, H: 1¼ turns)
|
||||
- [ ] **Run saw until warm** and observe behavior
|
||||
- [ ] **Fine-tune L screw** leaner if still stalling
|
||||
- [ ] **Fine-tune H screw** leaner if needed
|
||||
- [ ] **Verify 10+ minute run time** without stalling
|
||||
- [ ] **Test restart after warm stall**
|
||||
- [ ] **Clean air filter and spark arrestor** if needed
|
||||
- [ ] **Document final settings** for future reference
|
||||
|
||||
---
|
||||
|
||||
## 📅 Session Log
|
||||
|
||||
- **[2026-03-22 20:07]:** Issue documented - saw runs 5 min, stalls when warm, won't restart until cooled
|
||||
- **[2026-03-22 20:07]:** Suspected carburetor tuning issue (rich when hot)
|
||||
- **[2026-03-22 TBD]:** Next: Reset carb to factory settings and test
|
||||
|
||||
---
|
||||
|
||||
## 📝 Notes
|
||||
|
||||
- **John has spline tool** - Perfect for adjusting the carburetor screws
|
||||
- **Fuel and lube verified** - Problem is almost certainly carburetor related
|
||||
- **Classic symptoms** - This is a common carburetor tuning issue
|
||||
- **Quick fix likely** - Factory settings reset should resolve
|
||||
- **Document final settings** - Write down the L, H, and T screw positions that work
|
||||
|
||||
---
|
||||
|
||||
## 📊 Success Criteria
|
||||
|
||||
### Before Starting
|
||||
- [ ] Saw starts cold
|
||||
- [ ] Saw runs for 5 minutes
|
||||
- [ ] Saw stalls when warm
|
||||
|
||||
### After Repair
|
||||
- [ ] Saw runs for 10+ minutes continuously
|
||||
- [ ] Saw starts immediately after warm stall (no cooling needed)
|
||||
- [ ] Smooth throttle response
|
||||
- [ ] Proper idle (chain doesn't rotate)
|
||||
- [ ] No stalling or hesitation
|
||||
|
||||
### Verification Steps
|
||||
1. Reset carb to factory settings
|
||||
2. Run saw for 10+ minutes continuously
|
||||
3. Attempt to restart immediately after warm stall
|
||||
4. Verify no cooling period needed
|
||||
5. Document final screw settings
|
||||
|
||||
---
|
||||
|
||||
## 🧪 Revision History
|
||||
|
||||
| Date | Change |
|
||||
|------|--------|
|
||||
| 2026-03-22 20:07 | Initial issue documentation - carburetor stalling when warm |
|
||||
| | |
|
||||
|
||||
---
|
||||
|
||||
## 🔗 See Also
|
||||
|
||||
- [Main chainsaw project README](../README.md)
|
||||
- [ISSUE_TEMPLATE.md](../ISSUE_TEMPLATE.md)
|
||||
Reference in New Issue
Block a user