2008 400 trv artic cat

[The Picker]

Have  a 400 trv that is back firing and seem to loose gas supply on times and will not idle. It has a new plug and cleaned the air filter. Will air supply to fuel system do this?

[Travis]

sounds more like it's Carburetor cleaning time...

[The Picker]

There looks like a crack in the rubber on the intake gasket between engine and carb.

[Travis]

That could cause an issue... usually air leaks will cause the engine to surge though but i would replace the carb gaskets as a starting point.

[The Picker]

Is there a way to test for air leaks?

[Travis]

Get WD-40 or similar... something that the engine can burn as fuel.... gasoline not recommended though.

 In a TRIGGER spray bottle, no aresol can. and spray the WD-40 around where the carb mounts and intake gaskets. if there is any change in engine speed or it blows smoke, you have a gasket leaking...

Be sure to spray the area liberally.

[The Picker]

Can i use wd40 with a straw?

[Travis]

You probably could, i just use the trigger spray to eliminate the risk of a fire via the propellant.

[The Picker]

Do not have any thing in trigger spray.

[Travis]

i guess go ahead and try it with the can... just be sure not to get on anything hot i.e. the muffler/exhaust pipe.....

[The Picker]

Just another thought, could you use your air nozzle to try air on the area to see if it changes the engine?

[Travis]

That might could work.....

[The Picker]

Will try air first and post results.

[kenfain]

It needs to be something dense. Air by itself won't work. Just use the aerosol can. As long as you use something that's not flammable, it'll be okay. 

What you're listening for is the idle immediately smoothing out temporarily. Use the spray to pinpoint the problem. 

A smoke test is much more efficient. 

[The Picker]

Ran the engine after and noticed  exhaust vapor coming out of a crack in the intake manifold after i stopped the engine after running it for a couple of minutes.

[kenfain]

That could cause some of your problems. That needs to be sealed. 

[The Picker]

New part ordered.