Owner’s manual
Is 40 1 or 50 1 better for chainsaws?
For the Craftsman gas chainsaw model 358350870, 40:1 is the correct and better mix because it matches the manufacturer’s fueling specification. Using 50:1 in a saw designed for 40:1 reduces oil in the fuel, which increases wear risk in a 2-cycle engine.
What our manual specifies for model 358350870
Our fueling instructions call for unleaded gasoline mixed with synthetic 2-cycle air-cooled engine oil at 40:1. That equals 3.2 oz of 2-cycle oil per 1 gallon of gas. See the 358350870 owner's manual.
Quick mix chart
| Mix ratio | Oil per 1 gallon gas | What it means |
|---|---|---|
| 40:1 | 3.2 oz | More oil, correct for this model |
| 50:1 | 2.6 oz | Less oil, leaner lubrication |
When 50:1 is acceptable (and when it is not)
Use the ratio the manufacturer specifies for the exact model.
- Use 40:1 when the manual calls for 40:1 (this Craftsman 358350870 does).
- Use 50:1 only when the manual specifically states 50:1.
- Do not “split the difference” with a random ratio.
- Do not use automotive or marine 2-cycle oil; use air-cooled 2-cycle oil.
- Mix in an approved fuel container and shake to fully blend.
Why it matters
A 2-cycle chainsaw engine depends on oil mixed into the fuel for lubrication. Running too little oil (like 50:1 in a 40:1 saw) can increase friction and heat, leading to faster wear and potential engine damage.
Related maintenance tip
If your saw is hard to start or runs rough, fuel quality and mix accuracy are common causes. The tips for a hard to start chainsaw guide is a good next step after confirming the correct 40:1 mix.
Last updated: January 2026
What model number is the Craftsman 358350870 chainsaw?
The model number for this Craftsman gas chainsaw is 358.350870 (often written without the dot as 358350870). You can confirm it on the identification label and in the 358350870 operator's manual.
Where to find the model number on the saw
Look for the model number in one of these common locations:
- On the starter housing near the recoil handle
- On the rear handle area
- Near the fuel tank or oil tank area
- On a sticker or metal tag on the crankcase
- Printed on the cover page of the operator's manual
Why the dot matters (358.350870 vs 358350870)
Both formats refer to the same saw; the dot is a common formatting style used in manuals and labels.
| You might see it as | What it means | When it shows up |
|---|---|---|
| 358.350870 | Same model number | Operator's manual, ID label |
| 358350870 | Same model number | Parts listings, online search |
Why it matters
Using the exact model number helps us match the correct Craftsman chainsaw parts and diagrams, especially for fit-critical items like the fuel system, starter components, and cutting equipment.
If you are ordering parts, match the model number first, then match the part by name and ID, for example the chainsaw bar, 18-in 180SDEA041 if you are replacing the guide bar.
Last updated: January 2026
Where is the model number on a chainsaw?
On the Craftsman chainsaw model 358350870, the model number is typically printed on the product identification label on the saw body (often near the rear handle, starter housing, or fuel tank area). You can also confirm the exact model format in the 358350870 operator's manual.
Where to look on the saw
Check these common ID-label locations first (wipe off oil and sawdust so the print is readable):
- On the rear handle housing near the trigger area
- On the starter (recoil) housing side cover
- Near the fuel tank or oil tank area
- On the chassis/crankcase area behind the guide bar
- On a logo or warning label panel on the body
What the model number looks like
For this Craftsman saw, the manual shows the model as 358.350870 (you may see it printed with or without the dot). Use the same digits when searching parts.
| You see on the label | Use for parts lookup |
|---|---|
| 358.350870 | 358350870 |
| 358350870 | 358350870 |
Why it matters
The model number ensures you get the correct parts and specs for your exact saw. For example, bar and chain fit, fuel line routing, and starter components can vary by model series.
Quick tip if the label is worn
If the label is scratched or faded, clean the area and look for a stamped or printed ID on a secondary tag. Once you confirm the model, match parts by the model-specific list, such as the chainsaw bar, 18-in 180SDEA041 if you are replacing the guide bar.
Last updated: January 2026
