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White Blowby - 5 hp Robin

Discussion in 'Mechanic and Repair' started by njconstruction, May 14, 2006.

  1. njconstruction

    njconstruction LawnSite Member
    Posts: 19

    I have a 5 hp Robin engine, an EY20D, on a plate compactor. It starts up okay and runs alright with the air filter off but there is a large amount of white smoke coming out the breather tube. If I put the air cleaner on, then it blocks the blowby from venting and the engine starts to hesitate. I checked the breather assembly and can't seem to find a problem. Any other ideas before I break down and buy a new engine? Thanks.
  2. oldrustycars

    oldrustycars LawnSite Senior Member
    Posts: 301

    plates are hard on engines...lots of dust, and ive seen many that cracked the air filter housing allowing them to suck dist right into the engine. i'd like to see a compression test, i always do that first. you're sure it isnt overfilled on the oil, or that the oil isnt diluted with gas? always shut off the fuel on small engines before loading or transporting them. are you sure the filter is blocking the crankcase vent tube? it should be inside the filter so vacuum from the carb sucks crankcase vapor back into the engine to be burned. you may have the wrong filter, which may have caused trouble.
  3. njconstruction

    njconstruction LawnSite Member
    Posts: 19

    Alright, thanks for the reply, here's what I can see.... The compression seems to be alright, I don't have a tester unfortunately, but there is good tension on the starter cord and the engine does run alright, just with excessive blowby. The oil and the oil level should be fine - it was fine when I got the unit and I changed it myself anyway to rule that possiblity out. And with the filter basically what happens is that the engine starts to stall when the air filter is on - the air filter being on does force the engine to recirculate the blowby back into the carb and for some reason it doesn't like to burn it.... No clue really. If the air filter is off it runs better, just with a ton of white blowby coming from the crankcase vent tube. I suppose this is a larger problem than I first thought.

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