Outdoor Power Equipment and Small Engines - weed eaters

I have several weedeaters ( different kinds )I am thinking of fixing. MOst will run with fuel poured into carbs. When I pull the mufflers to check for scouring, any way of expressing here how much, if any, scouring is acceptable? Don't want to waste time and money if the least bit of scouring makes it cost prohibitive. Examble: running till hot, then hard to start or adjust carb properly.

Hello boman

Scoring of the cyclinder walls should not be present. However, some will be or most likely will be present in very used engines.

Best method, in my opinion, would be to check the engines compression. Small engine compression gauges are a must for the small engine mechanic or repair enthusiast.

A specialty tool worth having in the diy shop and one which does not cost much. They are available at some auto parts stores, local small engine repair shops or by phone through the part sources I provided in many of my prior posting replies.

Engines that run hot may have internal damage not worth fixing. Especially if you were not the original owner. Continued usage of an engine that was not properly maintained or run on fuels with incorrect oil to fuel ratios causes severe internal damages.

Engines such as those most likely are not worth the attempts to fix but do make good engines to practice on and learn about. If this is your intentions.

Regards & Good Luck.
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It's hard to draw the line as to how much scoring is unacceptable. Some engines will run well with a bit of scoring, some won't, and there's not really much of any way to tell how deep the scratches are by looking through the exhaust port. After years of experience, you pretty much know by looking which ones are good, and which ones are trashed. A compression test would be the best way, as Tom mentioned, and even then it can be hard to draw a line across the board as to what readings would be below par.

My suggestion to you is to buy a leak down tester. You run the engine till its hot and then you blow the cylinder up with air. If you buy one it will come with complete directions. They usually cost around $60. If it is the same as or more than 10% on four cycles or more than 8% on 2 cycles you would have to A replace rings or B at worse go to an oversized piston. Anoter tool can help you decide that. Inside Micrometers. Cheap but effective.

I just replaced the piston and cylinder on my Craftsman for $45.00. Thats just parts.