How to Repair a Blown $200 Husqvarna 545 MKII Chainsaw
Welcome back readers!
In this write-up, I'll be explaining the process of fixing a blown-up chainsaw.
The Husqvarna 545 MKII retails for $640 brand new, so when I saw it on Facebook Marketplace for $200, I knew I had to have it. The previous saw owner clearly showed that he knew nothing about saws and, frankly, had no business owning such a nice saw. There was USED motor oil in the bar oil reservoir, which ticked me off to no end. I went to start the saw and noticed that it had no compression. I wasn't immediately alarmed as some of these pro saws have easy/comfort start features. After about 5 mins of trying to get it running I paid him the money and took it home to inspect. Upon arrival, I changed the plug and it did fire, It just wouldn't stay running.
I took it to my local equipment repair shop and he took a quick look. After a failed compression test, he said that there was nothing that he could do. Defeated, I went home and completely disassembled the saw down to the piston. Upon inspection, I could clearly see that the engine was blown and would need some parts and cleaning, I bought a rotary tool from Harbor Freight as well as a high compression piston and ring kit from Lil Red Barn.
While waiting on the piston, I began removing the caked on Aluminum from the cylinder head with muriatic acid. Be careful with this chemical, it's some knarly stuff. After washing the cylinder down, I began cleaning up the ports by doing some light polishing. When the piston arrived, I installed it and put the head back on. I'd like to give you all a few notes on installation though. When you go to install the piston, ensure that the circlips are FULLY seated in their respective grooves. Failing to do so could lead to CATASTROPHIC damage later down the line. Another note, when going to reinstall the carb and air filter system, be sure to position the fuel line above the carb as failing to do so will result in a pinched fuel line.
After that, give her a tug and she should start right up! I do plan on installing a Steadfast Forestry Products muffler on the saw to see what the high comp piston and it will do. I'm confident that it will be one of the best 50cc saws to have on hand.
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