How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Rex L. Your Own Question

Rex L.
Rex L., Small Engine Technician
Category: Small Engine
Satisfied Customers: 691
Experience:  auto-diesel graduate. small engine and John deere and silver certified in stihl.
34138167
Type Your Small Engine Question Here...
Rex L. is online now
A new question is answered every 9 seconds

Oil cap is blowing off john deere 425 tractor. Is it pvc valve

Customer Question

Oil cap is blowing off john deere 425 tractor. Is it pvc valve or crank case breather clogged and how do you get to these parts to check. Where are they?
Submitted: 2 years ago.
Category: Small Engine
Expert:  Jeremy R. replied 2 years ago.
Hi, My name isXXXXX you for letting me try and assist you with your problem.
That sounds like a crankcase breather There's a hose inbetween the cylinders that comes out of the block. You can check to see if it's clear.
Customer: replied 2 years ago.
Tell me where does the hose connect on each end. You said it comes out of block, it where does it go to from there
Expert:  Jeremy R. replied 2 years ago.
It should come up to the airbox.
Customer: replied 2 years ago.
I checked that small hose. It is clear. ANy other ideas?
Customer: replied 2 years ago.
Relist: Incomplete answer.
Expert:  Rex L. replied 2 years ago.
Make sure you have a clean air filter. This system will not work correctly if the air filter is getting dirty or plugged up.You could also have a head gasket that is bad and letting compression into the crankcase. You can check a compression with a compression tester and the cylinders should check about equal. (140 to 170 psi). Also the dipstick should fit snug when pushed in and do loosen up over time and may need a new one. Check air filter first.
Customer: replied 2 years ago.
Hi,
Will check your suggestions out. Thank you. I want to give you a little more info about this engine. It is a Kawasaki 20 HP gas engine used in John Deere 425 lawn and garden tractor. I use a 54" mowing deck. I have heard that this problem can be caused by plugged pvc valve but don't know where this is located. Do you know anything about that. Also, I am getting positive pressure from dip stick tube. Shouldn't it be negative or slight suction from it? Let me know what you think. I will first change out air filter to see if that helps.
Bill
Expert:  Rex L. replied 2 years ago.
The pvc valve i believe on your model is in the crankcase vent that you have already check. A normal would be positive and negative pressure as the pistons go up and down. Usually you will have more positive as the engine gets worn. You will get more positive pressure if the rings are getting bad or head gasket blown. I would rather you run compression test on engine before you have head gaskets changed . They may be fine.
Customer: replied 2 years ago.
OK, one more question. If pressure test is low, what does that mean and what repair does that signify, especially if only one is low and how low from normal signals a need for repair. I have fairly constant positive pressure from dip stick tube, you are saying that's to be expected from old engine. No smoke from exhaust when running, so rings may be okay. I do get some oil build up around carburetor. Does that signal anything. Thanks for your prompt replay
Bill
Expert:  Rex L. replied 2 years ago.

If pressure is low it can be rings. Or you have a valve not seating correctly. If a valve is not sealing correctly it will allow compression bypass but it will put the compression in the intake or exhaust. If you have a cylinder testing low on compression spray some penetrating oil in spark plug hole and test again. If compression is much higher the rings are worn. (The oil seals the rings). You can also have a leak down test done and it will test the rings and valves at the same time. It requires a leak down test that a good shop will have but are kinda expensive.

Rex L., Small Engine Technician
Category: Small Engine
Satisfied Customers: 691
Experience: auto-diesel graduate. small engine and John deere and silver certified in stihl.
Rex L. and 5 other Small Engine Specialists are ready to help you

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Last | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Curtis B.

    Technician

    Satisfied Customers:

    6989
    have worked on and around most engine models for 35 yrs./Polaris ATV expert
< Last | Next >
  • http://ww2.justanswer.com/uploads/KO/koboma/2012-6-6_20917_DSCF1022.64x64.JPG Curtis B.'s Avatar

    Curtis B.

    Technician

    Satisfied Customers:

    6989
    have worked on and around most engine models for 35 yrs./Polaris ATV expert
  • http://ww2.justanswer.com/uploads/SM/SmEngPro/2012-8-5_3564_Rick1206290005Edit.fullres.logo.scrn.64x64.jpg Rick's Avatar

    Rick

    Factory Authorized Trainer

    Satisfied Customers:

    4126
    Outdoor Power Equipment technical trainer since 1990, covering eight states.
  • http://ww2.justanswer.com/uploads/GI/giftindex/2011-11-19_2715_JamesLWells500.64x64.jpg James W's Avatar

    James W

    Small Engine Troubleshooting Expert

    Satisfied Customers:

    2978
    7 years as Mechanic & Parts Manager for Brother who has Owned Lawn & Garden Repair shop for 35 years
  • http://ww2.justanswer.com/uploads/jonrk/2010-1-5_22551_jon.jpg Jon K.'s Avatar

    Jon K.

    Small Engine Diagnostic Expert

    Satisfied Customers:

    2950
    Gold certified Stihl tech, Service Manager for a rental/repair shop.Certified in most small engines
  • http://ww2.justanswer.com/uploads/MR/mr2cycle/2011-3-12_03458_sears.64x64.jpg Vince O.'s Avatar

    Vince O.

    Small Engine Technician

    Satisfied Customers:

    2374
    Over 30 years experience repairing lawn and garden equipment. Chainsaws, mowers,blowers and trimmers
  • http://ww2.justanswer.com/uploads/rheisnger/2010-12-31_010856_41385_100001225699183_7012_q.jpg RUSS's Avatar

    RUSS

    SERVICE TECHNICIAN

    Satisfied Customers:

    1723
    28 YEAR SERVICE TECHNICIAN
  • http://ww2.justanswer.com/uploads/BriggsEngines/2010-02-26_230200_n1834842973_4823.jpg CJBennett's Avatar

    CJBennett

    Small Engine Technician

    Satisfied Customers:

    623
    Briggs and Stratton Master Service Tech, Kohler, Tecumseh, Kawasaki certified. 18 years exp.