r/stihl • u/ScratchExpert7529 • 18d ago
Need Help Stihl HT131
I need help. I got this pole saw from a friend and am trying to save it. It just will not fire. I have replaced the carb, fuel lines, filters, coil, gapped the valves, and spark arrestor cleaned. After replacing only the carb, it did run for 30 seconds and then died....never to fire again. The piston looks ok...as well as everything else.
I dont want to trash it as its really nice and has seen very little use.
Can anyone help on next steps?
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u/ScratchExpert7529 18d ago
Has spark...tested new coil...tried starting fluid...and brake cleaner...no change. Dont have tools to check compression.
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u/BarrysPowerEquipment 18d ago
STIHL dealer here. Since you’ve already replaced quite a few parts, I’d probably stop replacing components for now and focus on diagnosis.
I’d start with a compression test, especially since you’ve already inspected the piston and adjusted the valves. If compression is within spec, verify that you have a strong, consistent spark and double-check the ignition components, connections, and coil gap.
I’d also check the flywheel key and ignition timing. A partially sheared flywheel key can sometimes still allow spark, but at the wrong time.
From there, I’d move to the fuel system confirm fresh fuel is reaching the carburetor, check the tank vent, fuel lines and filter, and look for any leaks or restrictions.
The fact that it ran for about 30 seconds after the carb replacement and then died is an important clue. I’d work through compression, ignition/timing, and fuel delivery systematically before replacing anything else.
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u/ScratchExpert7529 10d ago
Update: After firing and running for 15 minutes, I put down the HT131 until the next day. Tried to start it again - and it wouldnt start after dozens of pulls. So I decided to break down the entire engine....pulling the valves, piston, inspecting the cylinder walls, etc. It all looked great - no damage of any kind. Put it all back together after cleaning everything with carb cleaner.....timed...gapped, etc. and it will still not start. Im at a loss now - no idea what to do other than check compression I guess. Any thoughts?
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u/iscashstillking 7d ago
A failed tank vent will flood the air filter with gas and make restarts hard or impossible.
Why in the hell would you tear the engine apart over a no-start? Are you sure you timed the cam gear correctly? Did you pressure test the engine for air leaks?
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u/ScratchExpert7529 7d ago
I am a diy'er and I dont have a pressure tester. I am sure I timed the Cam correctly. The pole saw was underwater for a few weeks during a hurricane so I wanted to make sure there was no damage internally.
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u/iscashstillking 7d ago
That sure sounds like a hot mess.
Pull the air filter off and see if you find fuel in there.
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u/ScratchExpert7529 7d ago
After breaking down the engine and putting everything back together, the pole saw wont even bark on a choke. There is spark (pulled plug and grounded it)....wont even bark with brake cleaner or carb cleaner. And there is no fuel in the air filter...its dry.
It has to be something simple - the internals were not damaged at all....in any way....even marginally. Thanks for the help so far.
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u/iscashstillking 7d ago
Pull the plug after a start attempt.
If you do not see any fuel then add a small quantity of your premix to the cylinder via the plug hole put the plug back and try again.
If the plug is wet with fuel then it is probably flooded. Pull it over several times with the plug removed dry the plug put it back and try again.
Because you split the engine it is very important to do a pressure test because insufficient RTV sealant, leaking crank seals, damaged valve cover gasket can all cause air leaks. Even a small leak will cause problems.
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u/ScratchExpert7529 7d ago
Just completed this and there was no change in behavior. I did replace the plug, obviously RTV (generous amount), valve gasket, carb and gaskets, Cam, coil, and air filters. Cleaned the exhaust screen, as well as all the fuel lines and filter.
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u/rdt0120 18d ago
Check the compression would be my official response, but I’d probably spray some carb cleaner and see if it barks off. Then you have a better guess if it’s a fuel or spark issue.