360 kit build, advice needed

[Bob Smith]

I posted this in ask the experts and got no response so moving it to here for a try. when first start saw ran ok then began to slow and puff out the square hole below the carburetor opening, as seen with air cleaner off, now won’t start. Compression good, spark blue, new crankshaft seals, arm tired. This square hole looks like a vent to me and would only blow out air fuel if diaphragm was bad. Could this be the trouble?

 

[traffic903]

Got some photos mate?

 

[Pincher]

I am definetly no expert on much of anything, but if this is the square hole you are describing it should not have fuel coming out. It's only function is to vent to the air filter to compensate for plugging.

 

[Bob Smith]

Yes that’s it exactly, that’s what I was thinking. Does that mean a serious saw problem or just carburetor issue. Thought about rebuilding carburetor but just ordered new one from HL supply. Thanks for looking. A puffing off fuel and air was coming out as saw slowed and died.

 

[cus_deluxe]

Sure its coming out of there? My and other 660 kits (i know yours is a 360 kit) came with the carb metering level arm way too high causing severe flooding, and i was getting blowback through the carb. As said, there should be nothing coming out of that hole, it has no connection to the fuel system.

 

[Bob Smith]

Sure its coming out of there? My and other 660 kits (i know yours is a 360 kit) came with the carb metering level arm way too high causing severe flooding, and i was getting blowback through the carb. As said, there should be nothing coming out of that hole, it has no connection to the fuel system.

So what is the fix?

 

[Fruecrue]

Ripped diaphragm in carb?
I’ve heard of AM carbs with debris in them from manufacturing.

 

[Chainsaw Jim]

Here's a PDF file for Zama carb kits...

 

[Pincher]

For others that might want to help, here is his post from ask the experts.

I’m new here and need help. I just did my first kit saw and it was fun. It started right up and I adjusted the idle and was adjusting the high speed jet when it began to run sour and died. Now it won’t start. It seems to have good compression, and a good blue spark. I had the aircleaner off while running and as it quit fuel and air was puffing out the square hole at the bottom of the carburetor. Is this an indication of why it won’t start? I have newseals on both sides of the crank. And a new spark plug. What do you think?

 

[Fruecrue]

After reading that, I would have to agree with Custer.
Sounds like she flooded and had a bit of spit back.

 

[Bob Smith]

I think the diaphragm has a leak in it, going to take it in the House where light is better and check it out. Just ordered a new carb from HL supply. A kit was nine, while new was thirty. Will let you know when it is on. I still think there was air and fuel coming out of the square vent hole. But I was turning the high speed screw when it conked out.

 

[cus_deluxe]

The fix for me was bend the metering arm down. But if there truely is fuel coming out of that hole (“intellicarb” in stihl lingo) then a leaky diaphragm is virtually the only possibility.

 

[Bob Smith]

The diaphragm looks ok . Is there a setting for the metering arm? Or is bend it down exact enough? I pushed it until it has half the movement it had but still moves needle up and down.

So what is the fix?

maybee , I was pretty excited to was running. But won’t restart. What is a good high speed jet starting point?

 

[Fruecrue]

Metering lever should be flush with the body.
1 turn out on both H and L to start with.
If you think it’s flooded, don’t choke it, hold the throttle wide open and pull it like it owes you money.

 

[Bob Smith]

Had it running good on idle then held open to adjust high speed. Have cranked lots with plug out, new plug not wet, no pop. Compression valve in or out? I really can’t crank it much with it out.

 

[Fruecrue]

If it’s cold and dry, standard starting procedure.
Switch all the way down (high idle choke), pull till it pops.
Switch up one position ( high idle), pull til it starts,
Blip the throttle to move switch to normal run.

 

[Likesaws]

I’m no expert but you should learn to rebuild this carb also. Nothing wrong with ordering new one, but the more you learn about them the better you become understanding your saw. I’m still reading and learning a lot on here.
Great knowledge here and lots of people to share freely. Great place to learn.

 

[Pincher]

Might be time to learn how to press/vac test. Had a ms361 impulse line come off and quit running as you described. If a crank seal was installed too deep where it touches the bearing and failed is also possible.

 

[Bob Smith]

Might be time to learn how to press/vac test. Had a ms361 impulse line come off and quit running as you described. If a crank seal was installed too deep where it touches the bearing and failed is also possible.

Well I’ve got the carb off just pull the muffler and then plug it all up. Not to far from able to do that test. Then put pressure and vacuum through pulse line, right?

 

[Bob Smith]

Might be time to learn how to press/vac test. Had a ms361 impulse line come off and quit running as you described. If a crank seal was installed too deep where it touches the bearing and failed is also possible.

I put the case together with seals in place, after some study that worried me so I replaced them both. The flywheel side looked puckered .