Oily residue, smoke and constant bog

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I dont know if the tank vent is in the air box on that one. The 350 I worked on had the tank vent under the air box. Could be seen on the clutch side of the saw near where the front handle attaches to the tank/rear handle.
The primer suction side should hook to the carb. The output side of it should go back into the tank. Male sure thats not backward.
 
Replaced carb and no change. starts easily, idles well, maybe a little rough but idles w/o conking out. Give it gas and it bogs but keeps running and spews smoke and oil thru exhaust port, which is clean and clear. Everything look good.
 
I confirmed all fuel lines are routed correctly and blew them out. Still have not located the vent. What would be a symptom of a plugged vs open vent? Also, I have no idea how the ignition works on these small engines. Could there be some advance issue? It seems like it is running super rich due to amount of oil from the exhaust port. The cylinder looks good, I pulled the exhaust and ran it with it attached. If there was an air leak the thing would run lean, correct?
 
It certainly looks like it is getting too much fuel from somewhere. Chinesium carbs are a crap shoot. Looks like you crapped out! You need to pressure check the fuel inlet on the carb. It should hold 7-10 PSI forever. If it doesn't you have found your excess fuel leak!
 
The problem started with the OEM carb and I had to replace it because of a broken part on the idle screw. Installed new carb(s) and they both performed exactly the same as the OEM that is why I now don't think there is a carb problem since the problem originated with OEM carb. I have since replaced it twice and nothing has changed.
 
xerxes said:
The problem started with the OEM carb and I had to replace it because of a broken part on the idle screw. Installed new carb(s) and they both performed exactly the same as the OEM that is why I now don't think there is a carb problem since the problem originated with OEM carb. I have since replaced it twice and nothing has changed.
Click to expand...
Have you pressure tested either carb? That is where the excess fuel is coming from.
 
I don't have a tool to test the pressure but I would like to think I can probably rule out a bad carb being that I am on my third one. I have yet to locate the vent or know a way to test proper venting.
 
xerxes said:
Replaced carb and no change. starts easily, idles well, maybe a little rough but idles w/o conking out. Give it gas and it bogs but keeps running and spews smoke and oil thru exhaust port, which is clean and clear. Everything look good.
Click to expand...
Good indication of a bar oil leak into crankcase.
You said it was an amazon special, well I had one of those and it was not a clamshell. It also had loose case screws which caused the exact same thing
 
Brent Nowell said:
Good indication of a bar oil leak into crankcase.
You said it was an amazon special, well I had one of those and it was not a clamshell. It also had loose case screws which caused the exact same thing
Click to expand...

It's a Husqvarna 450 which is a clamshell engine.
 
Guess you tried it with the chain off? Drive sprocket or bar tip locking down, pinched bar.....
 
xerxes said:
I don't have a tool to test the pressure but I would like to think I can probably rule out a bad carb being that I am on my third one.
Click to expand...

Trying to troubleshoot a possibly bad OEM carb with unknown Chinesium replacements is foolhardy. You can't be sure of anything.

Option 1: Find an auto parts store that will loan out a pressure/vac tester.
Option 2: Find a store that has one on the shelf and carry your carb(s) in and "demo" their tester with your carb(s)!

The preferred model is a Mity-vac MV8500 which does vacuum and pressure. They have another model that only does pressure and a plastic "consumer" model.
 
I am very interested in your first post, when you said the idle on the original carburetor got "scaringly high"... that's often an indication of an air leak somehwere. All two stroke power equipment sold over the past decade runs pretty damn lean for emission and performance reasons and even a tiny leak is enough to screw up the air/fuel mixture and make them "race". Aftermarket carburetors are invariably non-emission compliant, meaning they will always run much richer than OE. That's how a lot of tiny bitsy air leaks are fixed nowadays, before dumping a ton of fuel in the cylinder to compensate for the air leak floods the cylinder. ;)
Personally I would at least plan checking that saw for air leaks if anything else "cheap and easy" doesn't work.
 
Conquistador3 said:
I am very interested in your first post, when you said the idle on the original carburetor got "scaringly high"... that's often an indication of an air leak somehwere. All two stroke power equipment sold over the past decade runs pretty damn lean for emission and performance reasons and even a tiny leak is enough to screw up the air/fuel mixture and make them "race". Aftermarket carburetors are invariably non-emission compliant, meaning they will always run much richer than OE. That's how a lot of tiny bitsy air leaks are fixed nowadays, before dumping a ton of fuel in the cylinder to compensate for the air leak floods the cylinder. ;)
Personally I would at least plan checking that saw for air leaks if anything else "cheap and easy" doesn't work.
Click to expand...
It was scarily high due to the carb being new out of the box and no adjustments. I should have zeroed out the H & L and idle and reset them. After I shut it down I screwed in the idle screw to zero and it was no less than 6 or more turns out. That was absolutely the reason for the high idle.
 
SteveSr said:
Trying to troubleshoot a possibly bad OEM carb with unknown Chinesium replacements is foolhardy. You can't be sure of anything.

Option 1: Find an auto parts store that will loan out a pressure/vac tester.
Option 2: Find a store that has one on the shelf and carry your carb(s) in and "demo" their tester with your carb(s)!

The preferred model is a Mity-vac MV8500 which does vacuum and pressure. They have another model that only does pressure and a plastic "consumer" model.
Click to expand...
I'll try to find one. I can also order one from AZ and just return it.
 
Couple of more stupid questions...
1. Try running it with the air filter off and see if that changes the behavior.
2. While it is running with the air filter off verify that the choke flap is fully open.
 

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