Question about Makita Saws
I'm a retired engineer and work PT as a tool tech for an HD rental ctr.
Compression on a new cylinder/piston is 160 psi. When it drops into the 130~140 psi range the saw becomes hard to start. Below 130 the saw will not run properly and at 90 they are toast. This is mainly due to improper fuel/oil mix (must be one bottle of 50:1 synthetic oil per gallon of regular gas. I use 6 bottles to 5 gallons for addition protection). Because this type of tool works in extremely harsh conditions (concrete dust) it is also imperative to keep the air filters clean. Wash the foam pre-filter after each use with plain water from a garden hose and discard after operating 6 times. Toss away (change with new) the paper filter if dust is present or when changing the pre-filter. Also check the carb hose to the cylinder inlet for cracks. My cost to get a cylinder/piston from Makita runs app. $130. When looking into the cylinder, streaks on the exhaust side indicate improper fuel/oil mix. Streaks on the intake indicate dirty air intrusion.
Posted on Nov 30, 2010
I got same problem ,i used my saw only ones.never again makita !!!
Posted on Jun 03, 2010
To know the Filters are clean the compression is tight the fuel and the GASKETS but also the seals of crankshaft are smooth they have high priority by this kind of saws for long lasting jobs (Dolmar) Makita models even the L+H ADJUSTMENT is so high important because much brands will have a default adjustment made and then the adjustments for fuel difference and after service and run-in period are forgotten and thats gives the worsed problem you can find the adjusters by most engines on differend brands are fixed in a [ Limited range of motion ] on base of exaust pollution emission of harmful gasses ask your dealer if the carburetor is have this special adjusters behind capped screws that liked on screws but are still for the real screw nozzles sometimes to buy a special adjustment screwdriver for it to adjust .
If you have informed by the dealer what he thinks is the best listen to the advise but if you have doubt between a rised problem after an expensive defect of a very young machine is to adjust the L nozzle clockwise so that it is made the highest rpm on half trottle turn clockwise asfar that the motor almost will stops that is the point from of to give back of that point a quarter turn back on yourscrew driver counterclockwise and now begin adjust the L nozzle a little bit in the both directions so you can hear its gonna react as fast as possible on the trottle then give a little fraction counter-clockwise only when pulling thetrottle react fast repeated and go then only to full trottle when the engine is a little bit warmed up a 4 minutes then make it full ttrottle and then turn the H adjustment easy much more counterclockwise then the H adjuster was adjusted from factory that will begive the most damaged saws if they have a yelling sound its became to hot and are to dry running it made the piston worn much more then you think but turn the H nozzle much enough (more fuel) so you can hear slowly release the rpm sound of the motor back and screw until the engine is beginning to give a little bit constantly a 4 stroke sound and play around that point test the saw on a good object and feelthat is having much more power then than you were expect then you know that its gonna get enough - fuel to lubricate the whole saw for shure a little bit ridge adjusted is better by alkylat fuel because that will give not hard peaces on the exhaust (grooved pistons) and used with a good fuel that its lasting longer then only a few years , alkylat fuel has a higher lubrication quality by different octane number by special engines with a special used decompressor thats why 1:40 1:50 mix in high quality alkylat is the same as even with normal Ultimate with a castrol 2 stroke 1:30 or 1: 33 oil mixture but the adjustments must be done on every service after a while when gaskets filters are replaced after a ew years and even sometimes by some sparkplugs . sparkplugs must having a whiteblue hearing spark if the spark is red colored then ask your dealer allways on motornumber and year of build for a new ignition coil if a replacement sparkplug is not give a smooth spark.
Posted on Dec 14, 2016
Your compression should be between 90-120 lbs on 2 cycle. Not enough compression
Posted on Mar 11, 2010
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