This carb bog is driving me nuts!!!

[DallanC]

This carb bog is driving me nuts!!! 92 PhazerII, sled ran flawlessly for years until this year when I started having no end of problems. The sled has a horrible bog just above idle. If you feather the throttle or flip the choke on off you can get it past the bog... after 3k RPM its runs perfect, screaming around the hills. Soon as you stop its a bear to get over the bog again. I cant tell if its running rich or lean during this bog. If you give too much throttle it will stall and wont restart easily unless you choke it (doesnt that mean its lean? If its dieing because its too rich, choke would make it worse wouldnt it???). The sled will happily idle all day long.

Anyway out riding again today and I had a idea... I made a small movie of the bog with my digital camera that hopefully someone can view, and give me ideas of what in the hell I can do to fix it.

2.5 mb. Click the link then select "Save As" and save it to your desktop, then play it.

http://www.huntingnut.com/images/temp/snowday/phazerbog.wmv

Please, someone out there has to have an idea of the cause is... /beg


-DallanC

 

[vern7483]

if your getting a bog early in the power, it is because your running lean. has it been colder than normal when u have been riding? colder temps will make it run leaner.

 

[vern7483]

i guess u could try to change your pilot jet, and have u cleaned the carbs lately? i have had similar problems on my yz 250 when it is a bit colder out, it will bog when i take off because its running too lean. it shouldnt have anything to do with your main jet since your pilot jet controls 1/4 to 1/2 throttle. let me know what u find out

 

[DallanC]

i guess u could try to change your pilot jet, and have u cleaned the carbs lately? i have had similar problems on my yz 250 when it is a bit colder out, it will bog when i take off because its running too lean. it shouldnt have anything to do with your main jet since your pilot jet controls 1/4 to 1/2 throttle. let me know what u find out

Phazers of that era have the pilot jets "plugged off" with little black plugs. Removal of the plugs thereby enabling the pilot jets removes all top end on the machine, odd i know but I ran into THAT problem earlier this year when first trying to solve this "bog" by enabling the pilot jets.

Today was very warm, 45degrees and the bog was worse if anything.

I may pull the carbs off again to go through them. It will make the 10th time this year pulling and checking them.


-DallanC

 

[snowdad4]

i would pay particular attention to the needle and seat and float height adjustment. then check crank seals. normally the pto side. last check, vacuum problem at the fuel pump due to deteriated fuel lines. you would be be surprised at how these lines dry and crack. if the supply lines are not easily flexible you may very well have a crack in them and sucking air, not fuel. hope this helps.

 

[RGM]

If it was running ggod and now isn't and it is 15 years old I would look at some of the rubber boots and crankseals to see if they are cracked and letting air in. Full power you might not notice it low power it wold make a bigger difference.

 

[MARCUSO]

When you drain your float bowls, check if there is water in your drain cap.

I had this problem with an outboard, and there was water in the fuel.

You could be sucking a drop now and then, and not notice it, but when it is idling, the water sits on the bottom, only to get sucked up when you burp the throttle.

 

[ArcticBoy]

Fresh fuel?? It don't take long for fuel to lose some of it's properties, many low end. Just a shot, good luck.