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Hot!Kawasaki KHT750 HedgeTrimmer

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2018/03/22 21:34:16 (permalink)

Kawasaki KHT750 HedgeTrimmer

I'm new to this forum.  Not a mechanic by any means.  However, I've learned I can usually repair my own gas lawn equipment if I just do a little research and try to do it myself.  Have generally been successful but this Hedge trimmer has me stumped.  The problem:  It starts easily and will idle forever but as I slowly give it gas the engine speeds up (as it should) but very shortly as you continue to increase the gas the engine begins to loose power and will completely stall if you gun it.  Once the engine has run for a good while and is nice and hot it will become easier and easier for it to stall as you start to give it gas.  I've replaced fuel filter, fuel lines, took the carb apart and cleaned it.  Took the spark arrester off (it was completely clogged) and cleaned it along with the air filter.  Tested the resistance of the ignition coil assembly; 9.8 is pretty much ok I think.  After all this it brings me back to thinking something is up with the carburetor again.  Does anyone have any ideas.  I bought this trimmer used last summer and would really like to get it up to speed (as it were).  Thank you to anyone who can provide any assistance.

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    Re: Kawasaki KHT750 HedgeTrimmer 2018/03/22 22:04:37 (permalink)
    The high speed circuit is still partially clogged. If disassembling and soaking it in a strong solvent like lacquer thinner, I hate carb cleaners like Gunk, and blowing it out doesn't solve the problem order a new carb. They are not expensive.
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    Re: Kawasaki KHT750 HedgeTrimmer 2018/03/23 04:22:39 (permalink)
    Whoa, wait a minute here Roy. Sorry I have to strongly disagree here about what to use to clean these carburetors.
    This a 2 cycle rotary carburetor you just don't throw a strong carburetor cleaner at them. It is a sure way to destroy a good carburetor. They have small rubber check valves that are easily damaged by these cleaners. They should never be cleaned with anything than soap and water in an ultrasonic cleaner; yes I said soap and water. Plus you don't use high pressure to blow the carburetor out for the same reason as it can and will damage those small check valves. No wire probing either. The strongest chemical that ever should be used is the fuel mix.
    As for a new carburetor it depends if it is even available as we don't have the full model number here plus they are not that inexpensive unless your getting a Chinese clone and that is pot luck on getting these clones to work. Or at least the KHT750D-A1 carburetor isn't inexpensive when it is at 75 usd.
    It takes a very good 2 cycle mechanic to repair these. I have been repairing these for 9 yrs professionally and still have problems with them myself. I have only have about 90% success repair rate with these rotary types but this is because others have already been in some of them (damaged beyond repair); of course, some have damage that can't be repaired to due certain parts are not available even they are listed the part lists. As for the other cubes I have about a 99% successful repairs.
    There are a couple critical adjustments that must be checked and made accordingly too. The metering lever must be set correctly so the main fuel mixture is correctly metered. Set wrong and it can cause either an over rich or over lean conditions. The metering diaphragm must not be stiffen. This setting of the metering lever can greatly throw off the idle mixture adjustment; though, some are EPA plugged to where they can't be adjusted easily. Some of these EPA plugs are not even removable once in place. Plus some may have a high speed mixture adjustment too. I just got though with Shindaiwa that its Walbro was a fully adjustable rotary carburetor but you do need mini single D tool to adjust it.
    And for the use of these strong cleaners in general I haven't use them for the last 5 years as I have completely switch over to soap and water for all of the carburetors that I clean. I ran a 2.5L ultrasonic cleaner my first a couple years as I switched over but quickly out grew it as I started doing larger carburetors on ATVs and I currently have two 10L units. One in full time use and the other as a backup. So much taking only 30-120 minutes most times instead overnight that I was doing even on those carburetor that I could use the dip cleaners on. I gave away my last can of dip cleaner (never even open it) 2 yrs ago and there not even a can of spray carburetor cleaner in my shop.
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