Super Jet Superjet low RPM bog???

[Malthe_Storm]

Hey i just bought a 1998 superjet, it was not running when i bought it. The ski is all stock except new fuel lines, but it is bogging down low, the ski would idle fine but at low rpm it would bog and want to stall, then once it hit the mid revs range it would rip and take off. is it running lean or rich ??

Thanks for the help

 

[Vumad]

Why wasn't it running? Did you open the carbs? You could have a clogged low jet or a leaking needle and seat. If it's truely bogging in a rich condition, do a pop off test.

 

[Jet_jase]

Could be the reeds, worth a check when pulling the carbs apart.

 

[Vumad]

I dont take my carbs off for that. Tilt the ski on the cart so its sitting on the lower side/bond rail instead of the chines abot 30 degrees diaphragm up. Take off the cover, test popoff on the ski. You can also take off the kidney and squirt out the jets.

This is by no means the right way to do a carb job, but its how we change our popoff and jets while tuning at the lake.

You can get a nice side ratcheting bit driver at home depot for less than 10 to do this job.

 

[Blue]

After market fuel lines tend to leak air into the system. Zip tie the connections and if the lines are clear look for air in the lines. Other wise bogging is a lean condition open the low screw a 1/4 turn and see if it helps.

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[Vumad]

After market fuel lines tend to leak air into the system. Zip tie the connections and if the lines are clear look for air in the lines. Other wise bogging is a lean condition open the low screw a 1/4 turn and see if it helps.

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You're the expert so I am no way doubting your advice. I thought a big was usually a term to describe a rich condition and a hesitation was a term to describe a lean condition. I usually associate a bog as the sound and performance of a motor that is loaded up. You seem to be indicating differently? Can you explain?

 

[john zigler]

"bogging" is a hard call. It is too much of a general description.

A lean condition can cause what some people call a "bog" (hesitation). This can be from dirty carbs, improper jetting, bad fuel filter, fuel select switch, fuel lines, tank vent, air leak in the engine, etc.

A rich condition will also create what some people call a "bog". This is not so much of a clean hesitation but more of a stumble that clears out when revved. This can also be from improper jetting, leaking needle and seats, etc.

Could also be something totally unrelated, like an exh leak, etc.

I also would ask, why it did not run originally, and what did you do to get it running?

Read up, and learn about "piston wash" This will give you a good idea of how your engine is running.

Remember, a lean condition ultimately can, and will end in engine failure.

 

[Blue]

Vumad. You are correct. I thought he possibly means its hesitating since it idles fine and runs great on topend. My guess is the fuel lines are leaking in air and making it lean on the bottom so its actually hesitating which is usually confused as a bog. It makes sense to me since the fuel lines are the only thing thats been changed. Typically the aftermarket lines are a tiny bit to big but guys run them since there colorful. Good call...

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[Th3g3rm4n4t0r]

Pull plugs and check them.. If one cyl is a diff colour then the other, check reeds if its a single carb setup.