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Subject: Synthetic oil in small air cooled engine

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Charles Krammin    Posted 11-29-2017 at 09:23:16 [URL] [DELETE]        [Reply] [Email]  
  • Synthetic oil in small air cooled engine
  • I have researched and fixed a Honda GC190 air cooled engine from a wood splitter, that used a synthetic oil. The original problem was a stuck decompression mechanism on the belt drive timing gear. Further observation was oil as black as spades, however the owner was very diligent in changing oil and documenting it in his cell phone. He was really PO'd when I suggested this normal human error. I changed the oil to 30W as recommended by the manufacture. I then sprayed the decompression mechanism with "PB Blaster and it went to working correctly.
    I then discovered he was using a synthetic oil. Further research on the web revealed ,from an expert, that "synthetic oil was not recommended for an air cooled engine, as it coats the cyclinder wall and with the next explosion cause carbon to get to the rings and causing further "blow by" and contamination of the oil.
    Synthetic works great in a car engine but not air cooled engines. Use what the manucture recommends" 30W or 10W30 for cool weather".
    Charles Krammin

    Walt/Tx    Posted 11-29-2017 at 12:01:15 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Synthetic oil in small air cooled engine
  • I happened to be working on a kohler 18 hp as I read your post and the manual states that syn oil is good for colder climates. Iím putting full syn in because the owner starts it and immediately throws throttle full open. Itís in a Snapper ZT mower. Iím impressed with the quality and design of this engine, first one Iíve worked on etc. Our local dealer support is terrible since owner change so I got the 100 page tech manual and went to work on it.

    Dean    Posted 11-29-2017 at 13:08:41 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Synthetic oil in small air cooled engine
  • Agreed, Walt.

    The owner's manual of my Kohler 20 KW whole house generator specifies 5W30 full synthetic oil in the Kohler air cooled engine.

    I use such and will continue to do so.


    Bruce Dorsi    Posted 11-30-2017 at 09:12:38 [URL] [DELETE]        [Reply] [Email]  
  • Not Kohler engines ???
  • Dean:

    One of my relatives is a Kohler generator (whole house) tech. ...He travels the area, doing set-ups (after others do the install), troubleshooting, & maintenance.

    He has been out to Kohler several times for Service schools and update seminars, and has toured the factory on those occasions.

    Just recently, he told me that Kohler does not make the engines on the whole-house units, but that they are re-badged engines built by GM. ....I was skeptical of this info, but he insists these small engines used on the 15K & 20K gens are not made by Kohler.

    I never heard of GM being in the small-engine business. ...Do you have any knowledge about this?

    He also said that some of the older Kohler whole-house units used engines made by B&S.

    The larger Kohler gens for industrial/commercial applications use Detroit diesels.

    Charles Krammin    Posted 11-29-2017 at 15:06:36 [URL] [DELETE]        [Reply] [Email]  
  • Re: Synthetic oil in small air cooled engine
  • Both Dean and Walt are correct in the use of synthetics as "there manufacture recommends it". Honda does not have that in there operators manual for certain engines (small GC 160,etc ) and operator would void there warranty by "not using the recommended oils". My observations support their recommendation.
    My point is: "operators of certain Honda small air cooled engines should only use the recommended oil 30W or 10W30." I feel it is their design chacteristics of those engines.
    Charles Krammin

    Walt/Tx    Posted 11-29-2017 at 18:12:04 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Synthetic oil in small air cooled engine
  • I might mention that this is a 2004 year model engine and manual so things may have changed on newer kohlers. Synthetic oil is sure pricey, $9.65 a quart at the zone for Valvoline 5-30.

    Dean    Posted 11-29-2017 at 19:23:35 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Synthetic oil in small air cooled engine
  • I usually buy Mobil 1 in gallon (5 qt?) bottles on sale for around $20.00


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