394xp vapor lock or something like it?

[stinkmonkey]

hi, am running a walkerized 394xp and am having a problem. when the saw has been cutting steady and is hot, if i run the tank dry i cannot get the saw restarted no matter what. till next day, then she fires right up. seems like vapor lock i used to get on an old truck. tried starting fluid, gas in carb, opening it up and pulling the plug to cool everything down, nothing seems to work. thanks for any ideas.
matt winfrey

 

[aquan8tor]

I get the same problem in mine, but usually if I keep pulling on the starter with the choke on, it eventually fires. I'm just tagging along to see the replies. Also, I notice mine is incredibly easy to flood when it is hot, and it is hot outside. Perhaps both of us have something out of adjustment.

 

[dtnodya]

I've found that a lot of things are difficult to restart if you run them out of fuel (trimmers, blowers, saws, etc) ... All of my saws are difficult to get running again if they are run dry. The only way I've found that helps is, right when I hear the saw bog the first time (running low on gas), I turn it of. Then when it cools and I refill it ... starts right up. I don't have an explanation as to why but that's what works for me.

 

[aquan8tor]

I use my 394XP for milling, so I never get a bog; it gets a surge of power as it goes lean, then it just dies. Waiting for it to cool is truly a PITA. I really think something is out of adjustment with mine, as I personally did the carb rebuild....... :bang: I got it tuned back up to spec with the same # of turns on each screw, then adjusted for idle & RPM WOT. It had the same problem beforehand. I refuse to believe that it is the same with all big saws. Do I have the jets messed up or something?? Obviously engines don't like to start when they're really hot, but there's got to be some catch that I'm missing.

 

[sILlogger]

i have ran 394's &395's cutting timber for a good while. i've had problems with the tank vent on them not functioning properly. a few times on brand new saws. the vent isn't drilled out from the factory. as the saw was ran it would run out of fuel...they tank vent was not allowing are into the tank and it was vapor locking. one way to check for this is when it has occured listen closely when the gas cab is opening and listen for an air "swoosh" as air is pulled in. check this and i would start with the tank vent. i hope thise helps i know how aggravating it can be

 

[troutfisher]

hi, am running a walkerized 394xp and am having a problem. when the saw has been cutting steady and is hot, if i run the tank dry i cannot get the saw restarted no matter what. till next day, then she fires right up. seems like vapor lock i used to get on an old truck. tried starting fluid, gas in carb, opening it up and pulling the plug to cool everything down, nothing seems to work. thanks for any ideas.
matt winfrey

After you run the saw out of gas, re-fill it, and try to restart....What does the spark plug look like? wet or dry?

 

[troutfisher]

I'm guessing it's either flooded, not getting fuel, or an electrical component is not working properly when hot. Does it still have spark after it's hot?

 

[aquan8tor]

Its got spark for sure, but I don't know about whether or not its wet. I don't think so, b/c it usually pops if I put some gas in the cylinder & try to start.

 

[stinkmonkey]

i have ran 394's &395's cutting timber for a good while. i've had problems with the tank vent on them not functioning properly. a few times on brand new saws. the vent isn't drilled out from the factory. as the saw was ran it would run out of fuel...they tank vent was not allowing are into the tank and it was vapor locking. one way to check for this is when it has occured listen closely when the gas cab is opening and listen for an air "swoosh" as air is pulled in. check this and i would start with the tank vent. i hope thise helps i know how aggravating it can be

that's a quote, i don't know how to do it other than cut and paste. it is from sILlogger.

did you find that once you let the swoosh of air into the tank it fired up? i have tried that, and it won't with mine. or is there something to check as far as the tank vent goes? does it get clogged or what? how would i go about checking it?

 

[sILlogger]

did you find that once you let the swoosh of air into the tank it fired up? i have tried that, and it won't with mine. or is there something to check as far as the tank vent goes? does it get clogged or what? how would i go about checking it?[/QUOTE]


yes after the tank pressure was released it would restart. tho not easily and would run until it vaporlocked again. mostly on ones that are nearly brand new saws. the problem was that the tank vents were not properly made out of the factory. the vent is plastic and the actual vent part(where air should be allowed to move freely) was not completely machined and didn't have a place for air to enter. if memory serves me properly a new vent is around $5 and has worked for me every time. ive seen it on a few of the 394 & 395's. the only way i know about going about checking it is to remove the tank vent and look it over.

 

[Lakeside53]

The reason many saws do not like to restart well hot after running out of gas is that you need choke to pull gas though the carb, but the saw invariably floods immediately the gas hits the cylinder.. great... a "half" choke would be nice... I HATE running out of gas in the middle of a big hot milling cut. PITA..

 

[aquan8tor]

as far as the vent is concerned, I know mine is clear; I checked it & its fine. No swish when its empty.

Lakeside, all I have to say is YUP, I hate running out in the middle of a cut too!!! I've started to refill the saw in between slabs! I get about 1 1/2 -2 slabs of 24" 8' hardwood per tank. PITA is right. Waiting for the saw to cool down w/air filter off is even more of a PITA.

 

[aquan8tor]

air filter off AND plug out!

 

[clearance]

I have a stock 394 and a Walkerized 395, I try to shut them off as soon as I hear they are out of gas. I remember when it was real hot we used to crack the gas caps on our saws (smaller XP Huskies). My big saws seem to fire up and run good, my 371 is the moody one.