Jump to content

Nominations for Tractor of the Month
Garden Tractors and Parts on eBay



Photo
- - - - -

Vapor Lock Issue?


  • Please log in to reply
17 replies to this topic

#1 ariensman2 OFFLINE  

ariensman2
  • Member
  • Member No: 8720
  • 8 Thanks
  • 22 posts
  • Location: Coastal Maine

Posted May 12, 2012 - 06:09 PM

We talked about this in the past but never came to a solution at that time. I have the kohler 14hp in my machine and it appears to run out of gas and stall after about 20 minutes of hard use mowing. It will start right back up if I let it rest for a while and go for another 20 minutes or so depending on the outside temperature. This never happens in the winter plowing snow but that is a much easier task for the tractor. In earlier posts we talked about relocating the exhaust to point away from the machine thinking the heat may be causing a vapor lock. I have done that but it didn't help. It doesn't appear to be overheating and runs very well when cooled down. Does anyone have any ideas how to prevent possible vapor lock or any other ideas what it could be? It has always done this all along even the previous owner told me it did that.


#2 Amigatec OFFLINE  

Amigatec

    Collector of Rusty Junk

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 5899
  • 2,023 Thanks
  • 3,172 posts
  • Location: Haskell Oklahoma

Posted May 12, 2012 - 06:56 PM

It sounds like the coil is getting hot.

#3 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 35,637 Thanks
  • 29,838 posts
  • Location: South Central Kentucky

Posted May 12, 2012 - 07:09 PM

It sounds like the coil is getting hot.


I agree it sounds like the coil breaking down. Next time be ready to test for spark as soon as she dies. Carry a good spark plug along so you can slip the wire on it just as soon as she dies. If no sparky, you simply need a new coil. If there is still a good hot spark, get back with us & we'll go from there.

#4 Amigatec OFFLINE  

Amigatec

    Collector of Rusty Junk

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 5899
  • 2,023 Thanks
  • 3,172 posts
  • Location: Haskell Oklahoma

Posted May 12, 2012 - 07:28 PM

Also you might feel the coil next time it does it. A lot of the time when the coil goes bad, it will be real hot, probably to hot to touch.

#5 HDWildBill OFFLINE  

HDWildBill

    Freedom is not Free. Thank those in uniform for your freedom.

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 6354
  • 8,705 Thanks
  • 8,559 posts
  • Location: Ga

Posted May 12, 2012 - 08:25 PM

The coil, spark plug or even the wire breaking down with the heat. Do like Daniel suggested and carry a spare spark plug. I you do have spark using the spare plug change out the plugs and try to start. Let us know what you find.

#6 Ryan313 OFFLINE  

Ryan313

    PK Fanatic

  • Super Moderator
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 7087
  • 3,239 Thanks
  • 5,159 posts
  • Location: Wallkill, NY

Posted May 12, 2012 - 09:23 PM

I was also thinking coil as I read this. Instead of carrying another plug, you can just grab the wire with your hand and see how hard it jolts you... :bigrofl:

#7 caseguy OFFLINE  

caseguy

    Connoisseur of Rusty Junk

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 906
  • 1,624 Thanks
  • 5,600 posts
  • Location: Edinburg, PA

Posted May 12, 2012 - 09:54 PM

I recently helped my Dad's neighbor get to the bottom of an issue like this. It would run great for 15 or 20 minutes, then it would start to sputter and miss really bad before it finally just quit. As it turned out, it was the coil that was failing at higher temperatures. I rebuilt the carburetor and changed out the fuel lines before I figured it out.
I have heard that if it is truly vapor locking, that putting a piece of aluminum foil (shiny side out) around the fuel line where it runs near the engine will sometimes solve the problem. I'd still do as everyone is saying and check the coil out first though. Don't be satisfied seeing one spark when you test it. The one that I did was still firing intermittently, just not enough to sustain running. Crank the engine through several cycles and see if the spark is good and steady.

#8 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,290 Thanks
  • 28,623 posts
  • Location: N. W. PA

Posted May 13, 2012 - 07:54 AM

I'll jump on the coil band wagon too. If it's been doing it for a while and recovering OK, take a look at the coil and see if it says anything on it. Someone may have stuck a 6v coil on it. We had a continental exhibit similar symptoms when we got it running one time, and we put a dropping resistor on it, wa-la no more problems. Seems the higher voltage coupled with the larger current flow the 6v was designed for will cause the coil to heat up pretty bad, depending on mfg. Throw a mile of spark, but not good for things.

Two other thoughts, if the spark isn't your issue.
I've had a Briggs develop sticky valve syndrome when it gets hot. Oddly, the time it took to release was just about the same time as it took me to go get the spark plug wrench and change the plug. Vroom. 20 minutes later, nada.

I think I read somewhere that the push rods on these can get gummed up and be a problem. This would also throw a no spark error, but not for the same reason.

With all your symptoms, i'd grab one of those inline $5 spark checkers and run it for a while, then you can monitor spark right off the bat when it dies.

#9 ariensman2 OFFLINE  

ariensman2
  • Member
  • Member No: 8720
  • 8 Thanks
  • 22 posts
  • Location: Coastal Maine

Posted May 13, 2012 - 03:45 PM

Thanks for all the tips. I do have battery ignition and a 12v automotive coil with the built in resistor. I will check all those things next time I use it hard. It only does this when mowing, the toughest job of all for my machine as the 60" mower is just too much for the machine and it runs real hard with the governor pulling in constantly so it lead me to believe it could have been a fuel issue.

#10 ariensman2 OFFLINE  

ariensman2
  • Member
  • Member No: 8720
  • 8 Thanks
  • 22 posts
  • Location: Coastal Maine

Posted May 25, 2012 - 07:26 PM

Well guys, I have the prognosis. It was the fuel pump. I bypassed it using just gravity feed and mowed today for an hour and a half and it never missed a beat. The fuel filter appears to stay at least 3/4 full most of the time. The pump still worked well and shoots out gas big time but it just appears to vapor lock or something and can't pull fuel through. Thanks for all your input.
__________________

  • MH81 said thank you

#11 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 35,637 Thanks
  • 29,838 posts
  • Location: South Central Kentucky

Posted May 25, 2012 - 07:30 PM

Thanks for updating us. Odd that it pumps fine, but stops later. It is likely some form of boiling fuel though, as when the fuel boils, the bubbles in the pump will prevent it from pumping, similar to cavitation.

#12 Ryan313 OFFLINE  

Ryan313

    PK Fanatic

  • Super Moderator
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 7087
  • 3,239 Thanks
  • 5,159 posts
  • Location: Wallkill, NY

Posted May 25, 2012 - 08:40 PM

I don't know why it would do that, I'm glad you got it fixed. With your PK, the entire gas tank should be over the carb anyway. I dont know why they put a fuel pump on it to begin with.

#13 Amigatec OFFLINE  

Amigatec

    Collector of Rusty Junk

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 5899
  • 2,023 Thanks
  • 3,172 posts
  • Location: Haskell Oklahoma

Posted May 26, 2012 - 04:19 PM

I have been told that gravity feed systems don't vapor lock anyway.

#14 MH81 ONLINE  

MH81

    Proud to be Deplorable

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 27,290 Thanks
  • 28,623 posts
  • Location: N. W. PA

Posted May 27, 2012 - 05:56 AM

Good to see you found the problem. Thanks for sharing the solution. More knowledge is a good thing.

#15 Alc ONLINE  

Alc

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 1094
  • 5,454 Thanks
  • 6,623 posts
  • Location: Bangor Pa

Posted May 27, 2012 - 06:21 AM

Glad to hear you found the problem , I wonder if the little rubber flappers used as check valves went bad form the new ethanol gas ? Yours might not as uncommon in the future , Al




Top