A cure is usually like this- Drill 2 or 3 1/2″ holes from the fan area to the carb box so cool air can blow in around the carb from the fan. Then drill 3 or 4 1/2″ holes at the back of the carb cover,above and behind the carb. Thus you have cool air blowing from the fan thru the carb box and out the back keeping the carb cool and hot air building up around the carb.
It would be rare to have an MS 440 vapor lock while running since the saw’s fuel tank and carburetor are well isolated from the heat of the engine and fuel that is flowing does not have as great a chance of getting hot enough to turn it into vapor. Vapor lock will usually manifest itself after shutting the saw off and then trying to start the engine within a few minutes after the fuel has been sitting in the carb and has had a chance for the radiating engine heat to raise the temperature of the fuel system components to a point where the fuel can vaporize. I asked my dealer today and he said that it didn’t vapor lock, he did some adjusting to it and said that it could be the fuel filter sticking in the gas tank somewhere, up out of the fuel to make it run like it was out of gas like I described.
Rapid Lesson Sharing Event Type: Chainsaw Vapor Lock Accident Date: July 1, 2013 Location: Aragon Fire, Cuba Ranger District, Santa Fe National Forest Narrative A sawyer was injured when gas from a Stihl MS460 chainsaw fuel tank ignited after the sawyer opened the fuel cap to release excess pressure in the tank. Sawyers should therefore always move away from any potential ignition sources prior to releasing the excess pressure in the fuel tank. Vapor lock occurs when the fuel within the fuel delivery system overheats and vaporizes too rapidly.
The Dolmar PS-6100 is a rather modern saw with reed valves which might help prevent vapor lock. Vapor lock on my PS-7900 doesn’t require 15 minutes, nor does my PS-7900 have to be sitting in the sun!Scenario:- run her hard, bucking cut after bucking cut continuously for up to a tank of fuel. EDIT:I think vapor lock is a carb issue, gas vapors building up or entering the carb prevent the diaphragm to pump fuel.
how to prevent chainsaw vapor lock Related Question:
What causes a chainsaw to vapor lock?
Vapor lock occurs when the fuel (usually gasoline) within the fuel delivery system overheats and vaporizes too rapidly. The resulting excess gas bubbles accumulate to the point of actually blocking normal fuel delivery.
How do you overcome vapor lock?
Once the fuel system has cooled, you can help eliminate any vapor left in the fuel system by first pressing the accelerator pedal slightly (do not press it to the floor) while cranking the engine. Once the engine starts, hold the accelerator pedal down until the vehicle runs smoothly, indicating the vapor lock is gone.
How do I stop my carburetor from vapor locking?
If you’re wondering how to prevent vapor lock, try using a thermal barrier like a heat shield, or heat sleeve. Whether you have a carburetor or use fuel-injection in your vehicle, vapor lock can bring your vehicle to a standstill causing hours of frustration.
What are two causes of vapor lock?
Vapor lock is caused by heat. Excessive heat from the engine, exhaust system, and/or outside temperature can cause the fuel to vaporize in the lines. Some winter fuel blends and high altitude can lower the boiling point of the fuel. This can also contribute to vapor lock.
Why does my chainsaw bog down when I give it gas?
If your chainsaw is bogging down when you give it throttle, this is often a sign of improper gas-to-oil ratio. If there is too much gasoline in relation to the amount of oil used, this is known as a “rich mixture” and can cause the chainsaw to run poorly.
Is there a fuel additive to prevent vapor lock?
The following are some practical tips for preventing vapor lock. ALWAYS USE FRESH FUEL WITH FUEL STABILIZER. Gasoline can go stale in as little as 30 days. Fuel stabilizer additives are available at most automotive supply stores.
Will a vapor locked engine turn over?
Proving the Problem Once it’s been shut off, however, it won’t restart. After sitting for an hour or two, it will start again and run with no apparent problems. To confirm a vapor lock problem, we installed a clear hose from the fuel pump to the carburetor inlet.
What temp does gas vapor lock?
When modern injection motors break down after traveling for a long distance, some might not be able to restart right away. This is because those new motors reach temperatures of up to 120–140 °C, and vapor lock is likely to occur at such high temperatures.
Does ethanol cause vapor lock?
Adding 10% of Ethanol to Gasoline – as is currently done in the USA – drastically reduces the V/L ratio temperature. Therefore a critical vapor liquid ratio, which can cause vapor lock, will be reached at lower temperatures with Gasoline-Ethanol blends than with regular Gasoline.
Does higher octane gas prevent vapor lock?
Octane ratings are an indication of the burn or flash rate of fuel. The higher the octane rating the lower the volatiles and the slower it burns. Now it makes sense to me, high octane fuel has fewer volatiles to slow the burn rate and fewer volatiles means less vapor lock.
Can vapor lock cause overheating?
Vapor lock can be for any pipe wehere the flow is stopped due to a pocket of air. Poor bleeding or burping of the cooling system can cause overheating so it is something that has to be done correctly.
What is the T adjustment on a Husqvarna chainsaw?
The T screw regulates how much fuel is sent to the carburettor while idling until the throttle is pressed. L Screw – With the chainsaw still running, take a screwdriver and turn the L screw clockwise. Keep turning it until the engine almost stops turning.
Should you start a chainsaw with the chain brake on?
Check the Chain Brake When engaged, the chain brake stops the chain from rotating around the saw’s guide bar. When using a chainsaw, you should always start it with the chain brake engaged so the chain does not move.
Why does my Husqvarna chainsaw dies when I give it gas?
A clogged carburetor is often caused by leaving fuel in the chainsaw for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the carburetor and cause the chainsaw engine to stall.
What does a spark arrestor do on a chainsaw?
The spark arrestor on your chainsaw prevents dangerous hot sparks from igniting fires while you’re working. If the arrestor is clogged or dirty, however, it will also prevent exhaust from leaving the motor, which can prevent it from running.