suddnely not liking restarts

[tor*p*do]

my SN used to restart at the touch of a button
now it wants gas and cranking
plugs look fine, piston wash a tad rich
ported 61x/61x, 35 cc domes, MSD, B pipe headpipe and C4 chamber
mikuni 46 commercial with 120/150. 1 1/2 turns hi and low, 2.5 n&s
still runs strong, no hesitation, bogging etc.
rebuilt carb over the winter everying in

 

[tor*p*do]

any ideas?
just kind of annoying, maybe carb spring is getting weak?

 

[augustaf]

"now it wants gas" , you mean you have to give it some throttle to start if sitting longer than a few minutes? Might be flooded due to leaking n/s, or did you replace that when you rebuilt the carb?

 

[tor*p*do]

I mean, if you just crank it without pumping the throttle it wont start
when hot. cold starts are fine
did not replace n&s, but they are fairly new
tried richening up the lo spd screw but that didn't help

 

[Dirtybird]

My fx-1 is doing this same thing right now.
Just keeps cranking when hot.
Like out of gas.

Cold starts right up.

 

[mxmark4]

Mine does it toohave to hold wot to get a hot restart . Have never opened this carb up will have to pull it off and check pop off and see if needle and seat are leaky.

 

[DAG]

take the tank one way off and go for a spin

 

[augustaf]

Mine does it toohave to hold wot to get a hot restart . Have never opened this carb up will have to pull it off and check pop off and see if needle and seat are leaky.

Mine does it toohave to hold wot to get a hot restart . Have never opened this carb up will have to pull it off and check pop off and see if needle and seat are leaky.

When you shut a ski off there will be some pressure in the tank which might leak past a n/s that's worn. This gas ends up in the bottom of the crank case. If you now try to start the engine those addn. fuel vapors will cause a "flooded" condition. Holding the throttle wide open runs more air through the engine alleviating that flooding. When the engine is cold it does not mind that excess fuel. I even have to treat my dang Ryobi weed eater like that should I choke + prime it too much.

 

[Dirtybird]

Ok so carb rebuild is in order?
That is exactly what its like,flooded.
Almost restarts the same as when you have an exhaust leak under the hood.
Thanks

 

[mxmark4]

Iknow my one way vlave works b/c during the winter I un hook my fuel line from carb and blow into my one way valve to push fuel out into a can for starting fires. Also when its hot outside I have to keep my tank lid cracked to keep it from building up too much pressure.

 

[BruceSki]

When you shut a ski off there will be some pressure in the tank which might leak past a n/s that's worn. This gas ends up in the bottom of the crank case. If you now try to start the engine those addn. fuel vapors will cause a "flooded" condition. Holding the throttle wide open runs more air through the engine alleviating that flooding. When the engine is cold it does not mind that excess fuel. I even have to treat my dang Ryobi weed eater like that should I choke + prime it too much.

I really enjoy reading correct and knowledgeable information. Some people on here just spew some idiotic stuff sometimes.

Thanks for dropping some knowledge!

 

[jetpilot36]

i would just eliminate the one way valve. just run an open line to the gas tank so it has atmospheric pressure all the time.

 

[BruceSki]

With a full tank of gas it spews gas all over the engine compartment without a one way on the tank. Or it dumps water into your tank if you have an open line running up the handlepole.

Yamaha designed it with a valve for a reason.

 

[mxmark4]

I thought it won't t run right without it? Seemed like i had a kawi with a bad one way that wouldnt run right until l i replaced it

 

[augustaf]

you might try turning off the fuel valve when you shut down the engine. If it seals well enough that might help your issue or at least help resolve it.

 

[DAG]

With a full tank of gas it spews gas all over the engine compartment without a one way on the tank. Or it dumps water into your tank if you have an open line running up the handlepole.

Yamaha designed it with a valve for a reason.

If a ski will only run or run better by the fuel tank being pressurized, then the carbs need attention because they are not doing their job correctly.

A super easy "test" is to just remove the one way go for a ride and report back weather it helped or not. Takes less than 5 seconds

 

[mxmark4]

Im goin out on my lunch break today so i guess i could pull it off and see how she does.

 

[BruceSki]

If a ski will only run or run better by the fuel tank being pressurized, then the carbs need attention because they are not doing their job correctly.

A super easy "test" is to just remove the one way go for a ride and report back weather it helped or not. Takes less than 5 seconds

I pull mine off all the time to get the gas tank filled to the very top with fuel. On occasion I have forgot to put the vent back on and took off riding. The gas spewing out of the tank and into the hull (maybe into the carbs?) most certainly made it run like crap.

Just my experience with doing that.

 

[XJCrawler]

When you shut a ski off there will be some pressure in the tank which might leak past a n/s that's worn. This gas ends up in the bottom of the crank case. If you now try to start the engine those addn. fuel vapors will cause a "flooded" condition. Holding the throttle wide open runs more air through the engine alleviating that flooding. When the engine is cold it does not mind that excess fuel. I even have to treat my dang Ryobi weed eater like that should I choke + prime it too much.

I really enjoy reading correct and knowledgeable information. Some people on here just spew some idiotic stuff sometimes.

Thanks for dropping some knowledge!

The post above is a good example of correct knowlegeable information, the post bellow is the exact opposite of that

i would just eliminate the one way valve. just run an open line to the gas tank so it has atmospheric pressure all the time.

 

[xXx Octane xXx]

Apparently Mikuni is now offering a N&S that is more resistant to the ethanol (10% in most pump gas) than their standard Viton N&S.

If you have access to non-oxygenated (ethanol free) fuel and you aren't opposed to paying a little bit more for it, you can save yourself the headache of having to replace the soft goods in your fuel system so frequently.