Question about Makita Saws
Check to make sure you didn't accidentally plug up the exhaust port, or pull a wire lose. I don't think it can be anything else, IF it was running well before you did anything. How long has it been sitting? old gas can gum up carbs and or injectors. IF it was running and replacing the muffler made it not run, all it can be is a plugged exhaust, or a wire erroneously pulled loose.
Posted on Oct 01, 2019
SOURCE: makita 6410 petrol disc cutter
First of all, make sure you have followd the correct start up procedure.
(1)Throttle on and locked in start position, (2)choke on and pull a few times. Saw should fire briefly and cut out. (3)Now switch to idle (half choke if applicable) and pull another couple of times. Saw should now fire and run. If you have pulled it too many times in the full choke position you will have flooded the engine. To rectify this you will need two people. One of you should hold the machine steady on the ground with no choke on and throttle fully open. The other should also steady the machine and pull the starter in quick succesion. This could take ten or so pulls but it should start the engine in the case of flooding. Sometimes it will splutter a couple of times before fully starting and it will normally bog down a bit for the first few seconds as it spits out the excess fuel/oil mix.
If you got to point (3) as it shown above, and then the saw wouldn't start, or hadn't fired and died then there could be a few different problems. basic checks are for, clean filter, fresh/clean fuel, clean spark plug (ie, not oily/choked with carbon build up). When checking the spark plug, if it has fuel/oil mix on it then ther is probably aeither a compression problem/air leak or no spark. To check for a spark leave the plug unscrewed but fitted into cap, rest it against a metal part of the saw and pull the starter with the elec switch on. You should see a healthy blue spark. WARNING, do not rest the spark plug near the plug hole as if it does spark it could ignite any fuel/oil mix that is pumped out of the cylinder. I've had many a singed eyebrow from this happening. If there is no spark, check to make sure the cap is attatched securely to the lead,and try repacing the plug. If this doesn't help you will need to get the coil, ht lead and wiring tested.
Posted on Nov 01, 2008
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
SOURCE: Ive got a Makita concrete
The manual says to mix it 100:1 if using Makita high performance oil or 50:1 using regular Makita 2 stroke oil. I'd go 50:1 with non Makita oil too.
Here is a site to download a pdf manual if you need it.
Posted on Feb 18, 2011
You need to make sure it is mechanically sound, has the piston picked up on the exhaust side? does it have enough compression? is there signe of concrete dust on the inside of the air filter and filter houseing?there are many after market carb gasket sets, some have a small hole missing from the diaphram and gasket on the metering side, this activates the compensator, this needs to be there as the metering cover has no breather hole in it.
Posted on Mar 14, 2012
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