Vaporlock revisited

[BobRip]

After dealing with stalling from vapor lock for some time now, I believe I have finally got mine to stop. I purchased a new OEM fuel pump for my Robin 422. (I think the heat may cause the internal parts to wear out before their time.)

If I can buy a new pump every few years, I am not happy about it, but I feel it's worth the $41 to stop the problem. Some part dealers sell the internal parts to rebuild the pump, but those parts added up to over $25 so I just bought the complete assembly from Jacks.

Replacement Parts for Robin Model EH63, EH64 & EH65

Just to let you all know, I tried many things such as moving the gas lines, insulating the lines, insulating the muffler and even moving the original fuel pump. None of the options helped and the PT would sputter and die after an hour of mowing or other uses. I decided to buy the new fuel pump this mowing season and have not had a problem yet this summer.

Good luck.
Joe

Joe, I believe that the new pump puts out 2 psi instead of 1. I think this will help to give you a long term solution.

 

[washita]

this is how I fixed the VL problem on my 2007 model 425 please note a motorcycle style baffle is in the straight pipe (keeps the neighbors on good terms) I also welded a longer stud onto the carburator so I could use commonly available Kohler airfilters

 

[washita]

a little more info the muffler was replaced because I accidently backed into a tree and bent it original muffler had approximately 12 3/16'' diameter holes on inlet and the same on outlet pipe suprised the motor could run with such a restrictionreplaced with straight pipe with internal bafflenow it starts quicker it uses less fuel and no air bubbles in fuel cell, plus no backfiring when shut off and no more glowing pipes when working at night I have been checking my plugs to make sure I am not leaning out the motorI guess the fix was acheived through accident/incedent I have also noticed the engine runs best on 89 octane fuel not sure why maybe more complete combustion? thoughts on the octane?

 

[PABenz]

Just an update on my vaporlock problem. I have not had it happen since I put the new fuel pump in my 2004 PT422. I had tried several things with the gas lines and some of the other suggestions over the summer before last and this was the only thing that has entirely stopped VL for me.

I am very happy to have not had any vaporlock problems this past summer and I sit ono the PT and sometimes mow for 2-3 hours straight (except a stop to refill my beverage now and again). Of course, grass is a distant memory right now.

Happy Plowing
Joe

 

[MuncyBob]

I just replaced my fuel pump with the same one mentioned from Jacks. They have a screen on the backside of the shell that I did not know was there and my old pump's screen was completely blocked up. What is the screen for(some sort of air mixture?)...would this being blocked also shorten the life of the pump? I'm sort of glad I did the swap out as the short piece of fuel hose into the fuel filter was nearing the end of it's life so I replaced that and also the fuel filter. An exact match for the fuel filter on the 422 is a Purolator #F21124. Tomorrow I take the carb off and hopefully after a good cleaning the surging will go away and it will run like it should. Recently replaced a few hydraulic hoses too...near 400 hours on the 422 and this is the only non-regular maint. work I have had to do so I feel pretty good about that!

 

[cqaigy2]

I've never noticed the screen your talking about, but my eye sight leave a little to be desired. be sure to check the connection on the fuel tank, ive had a lot of sealer crap end up in the elbow and get hung up in the fuel shut off valve. Mine runs much better after cleaning all that stuff up and replacing the fuel pump.

 

[MuncyBob]

Well, got the carb off and cleaned it with carb cleaner and compressed air. With some help we had it back on and running in about an hour. What a difference! Ran awhile today and reminded me of how got she ran the first year I had her. I didn't run it hot enough to test vapor lock...that will come with the next grass cutting. I was so inspired that at the end of the day I decided to wash her for the first time in 2+ years. So purdy now!

 

[MuncyBob]

Vapor lock seems to be gone for me. As previously mentioned, I believe it was the replacement of the fuel pump. VP only started with me about 50 hours ago so a worn out pump makes sense. I guess I can live with a new pump every 350 hours going forward.