Oily residue, smoke and constant bog

[TBS]

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.

My husqy/craftsman 445 had some issues with the choke hanging at half when it was new, linkage was bent to much during assembly.

 

[xerxes]

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.

Yes, filter off, choke open.

 

[SteveSr]

Yes, filter off, choke open.

Any chance that you could post a video of it running? Might provide some more useful information.

BTW, H & L carb needle settings are calibrated on OEM and name brand (Walbro, Zama) carbs. For carbs without limiting caps it is usually 1T out from lightly seated. You might try this with your AM carbs and see what happens. The idle screw adjustment is meaningless as all it does is open the throttle plate. You can start by setting it so that it just cracks the throttle plate and go from there.

 

[xerxes]

Any chance that you could post a video of it running? Might provide some more useful information.

BTW, H & L carb needle settings are calibrated on OEM and name brand (Walbro, Zama) carbs. For carbs without limiting caps it is usually 1T out from lightly seated. You might try this with your AM carbs and see what happens. The idle screw adjustment is meaningless as all it does is open the throttle plate. You can start by setting it so that it just cracks the throttle plate and go from there.

Absolutely

 

[xerxes]

Link to video

 

[Deleted member 117362]

Just had a 365 do the same thing, try a different ignition module.

 

[rupedoggy]

Three things to try.
1.turn the "H" needle in or clockwise
2. check the lever height in the needle/fulcurm section of the carburetor, also known as the metering chamber.
3. Reset the air gap on the coil and the spark plug.

 

[sunfish]

Damn, that's very strange.

 

[xerxes]

I have adjusted carb to no avail. Not make a bit of difference towards improvement. I've done it. I had thought about the ignition module, I just have not disassembled to that point yet. Coming soon though to check the vent and test vac and pressure.

 

[Deleted member 117362]

As said, reset air gap and make sure flywheel key has not sheared off, making timing off. If all is fine, I would try a different module.

 

[Brent Adams]

That definitely sounds like ignition problem. Go for the OEM module. I've tried Chinese ones. Last one wouldn't work at all out of the box.

 

[Brushwacker]

After rereading all u done , the vidieo , i think most likely he is correct.

That definitely sounds like ignition problem. Go for the OEM module. I've tried Chinese ones. Last one wouldn't work at all out of the box.

 

[SteveSr]

I have adjusted carb to no avail. Not make a bit of difference towards improvement. I've done it. I had thought about the ignition module, I just have not disassembled to that point yet. Coming soon though to check the vent and test vac and pressure.

So what is the history of this saw and what happened just before it started to run like it does in the video?

 

[SteveSr]

Hello, I have a Husky 450 that developed an intermittent problem with what seemed to be a carb issue so I replaced the carb. After the replacement, it started easily and I cut a good size log for testing and the only issue was that the idle was scary high with chain buzzing around. After making that adjustment I put the saw away for the day. The next day it started easily but the motor would not accelerate and all I can manage to get it to do is idle. When throttling up it just delivers a constant bog and the RPMs never increase. Oily residue and smoke coming from muffler. New gas filter and new gas, checked for kinked and or lines with holes or tears and not found any (maybe I missed a line problem?) to be an issue.

Carbs don't generally get intermittent or fail suddenly. Electronics can. If the flywheel key is intact and the coil spacing good I see a new ignition module in your future...

It is, however, exhibiting similar symptoms to the carb metering needle not seating and pumping way too much fuel into the engine.

 

[Manic84]

If I missed it sorry, but have you tried a different spark plug?

 

[xerxes]

If I missed it sorry, but have you tried a different spark plug?

many

 

[rupedoggy]

Have you tried putting on red shoes, tapping your heels together three times and saying "there's no saw like a 450.............." LOL

 

[Manic84]

many

Well... that answers that.

Alright, I have one more stupid question...(a two for one!)
How do the linkages and secondary intake butterfly/lever look? (couldn't quite tell from the vid)

I remember a few "strato" engines that weren't opening fully had similar symptoms of not reaching full rpm,
if everything looks alright, the coil is faulty (as others have said) and it needs to be replaced. (I don't know if these coils have a limiter of some kind or not)

 

[Jkstihl]

Turn the L back in and use the idle adjustment screw out to adjust the idle down instead.

 

[xerxes]

Finally fixed. Ignition module was the culprit. Thanks for all of the help. Next problem... a rigid generator.