Stihl 038av no start, no presure gasoline in the tank.

[kppus]

Hello, I have a stihl 038 chainsaw and I have a problem. I upgraded the 52mm cylinder and it doesn't want to start. I checked the spark plug and it has sparks but I saw that I had no pressure in the tank. I also changed the pressure valve on the tank and it still doesn't start. How much is the problem? Thank you!

 

[stihltech]

Did it run before the upgrade?

 

[Mad Professor]

Is the inside the air filter, choke working? Try giving it a splash of mix in the carb and see if it pops.

There is no "pressure valve", the vent is a piece of tubing with two screws (grub screws) in it. The tank is vented so should not have pressure.

 

[HarleyT]

Look at the flywheel key

 

[kppus]

Did it run before the upgrade?

Yes !

 

[HarleyT]

Yes !

Then check your flywheel key.

 

[a. palmer jr.]

Also you might check your compression. Sometimes the new kits don't have much compression at first. Pour about a half a teaspoon of fuel mix in the sparkplug hole and try starting it..

 

[Isidro]

Is the inside the air filter, choke working? Try giving it a splash of mix in the carb and see if it pops.

There is no "pressure valve", the vent is a piece of tubing with two screws (grub screws) in it. The tank is vented so should not have pressure.

 

[Isidro]

Question: why does the 038 have the tubing that connects to the fuel tank but has two grub screws in it? It seems very strange to me. Sorry, but I can not figure out what the need is for this tubing that is blocked or it function. How is this tubing a vent?

 

[a. palmer jr.]

Stihl has been experimenting with different kinds of tank vents when they could just use the Echo mushroom type one way valve on the end of the hose instead of the two screws. I think they did eventually go to something like that on later versions..

 

[Isidro]

Thanks for your response to my question. The two screw in the "vent hose" does not seem to me to be venting anything. The Echo mushroom type vent clearly is a gas tank vent.

Stay safe, I

 

[Mad Professor]

Thanks for your response to my question. The two screw in the "vent hose" does not seem to me to be venting anything. The Echo mushroom type vent clearly is a gas tank vent.

Stay safe, I

Those type of vents have worked fine for 40+ years in Stihl saws. Properly installed they are cheap to fix/replace and effective.

The screws should be pushed, NOT SCREWED into the tubing. The tube vents along the grooves in the screws which are not threaded into the tubing.

I've have several 038 saws. I've only had to work on the vents twice in 30 years. One of the saws I got for free, was filthy, and the tubing needed to be cleaned inside. On another the 30+ year old tubing began to disintegrate and had to be replaced.

 

[a. palmer jr.]

Those type of vents have worked fine for 40+ years in Stihl saws. Properly installed they are cheap to fix/replace and effective.

The screws should be pushed, NOT SCREWED into the tubing. The tube vents along the grooves in the screws which are not threaded into the tubing.

I've have several 038 saws. I've only had to work on the vents twice in 30 years. One of the saws I got for free, was filthy, and the tubing needed to be cleaned inside. On another the 30+ year old tubing began to disintegrate and had to be replaced.

I wonder why Stihl changed their design...

 

[stihltech]

EPA

 

[pioneerguy600]

I wonder why Stihl changed their design...

The grub screws in a line were a two way vent that the EPA banned for all gasoline appliances, the newer vents are a one way type, air in, no gasoline vapors out.

 

[a. palmer jr.]

The grub screws in a line were a two way vent that the EPA banned for all gasoline appliances, the newer vents are a one way type, air in, no gasoline vapors out.

Besides that, they leak when turned over on their side..

 

[Jeffrey F.]

I put a new fuel line in there and stuck a duck bill in it.

 

[Mad Professor]

Besides that, they leak when turned over on their side..

I'll check that next time I fill up one of my 028/038 saws. EPA can suck my........

I like the new vents as much as flippy caps, choked down exhaust/cat converters, and Hi/Lo limiter caps

I miss this guy.......

 

[Bob Hedgecutter]

Besides that, they leak when turned over on their side..

Is that not the entire guise behind two way? Lets something in one way, but also allows something out in a second way = two way venting.

 

[pioneerguy600]

I put a new fuel line in there and stuck a duck bill in it

Is that not the entire guise behind two way? Lets something in one way, but also allows something out in a second way = two way vent

I put a new fuel line in there and stuck a duck bill in it. View attachment 1017071

That duck bill looks to be too tight to vent, did you try pulling vac on the tank after install?