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Jeremy R.
Jeremy R., Technician
Category: Small Engine
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Experience:  15+ years of experience and a business owner.
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I have a Troy-bilt TB465SS 4 cycle gas trimmer. It wont start

Resolved Question:

I have a Troy-bilt TB465SS 4 cycle gas trimmer. It won't start and has a very weak orange spark. Also, compression is only ~50 psi (ran with drill motor). Both valves look good with no burning. Re-lapped valves and still 50 psi. Cylinder wall and rings look good. Probably less than 50 hours on engine. Trying to decide whether to replace ignition coil or just can it.

Is 50 psi OK or not?
Submitted: 4 years ago.
Category: Small Engine
Expert:  Jeremy R. replied 4 years ago.
Hi, My name isXXXXX you for letting me try and assist you with your problem.
No sorry 50 psi is not enough. you should have over 100 psi in that machine.
Maybe a ring is sticking to the piston?
Either way it's way too low to run.
Customer: replied 4 years ago.
rings are not stuck, when I pressurize cylinder with compressed air can feel leaks out both intake and exhaust ports. valve seats look uniform as do mating surfaces on the valves, I just don't get it
Expert:  Jeremy R. replied 4 years ago.
If you're feeling air leaks then obviously the valves aren't closing all the way.
It's extrememly strange for this sort of unit but I'd definately say that you have found the problem.
Why they're that way though I wouldn't want to even begin to guess.
You can adjust these on the rockers to see if they are just too tight there.
You don't have anything to lose at this point.
Customer: replied 4 years ago.
I did the pressurization test with the rocker arms completely off the engine. Seems like the valves are hitting something before they seat.

Any way thank you for your help. I think I have a bucket of scrap metal. Price of parts would approach that of a new machine. What trimmer do you recommend for home use? I really hate mixing oil and gas but this has been a bad experience with the 4 cycle.
Expert:  Jeremy R. replied 4 years ago.
I buy the $65 featherlite weed eater wal-mart sells personally.
They usually last me about 4 years.
Every 4 or 5 years I go buy a new one.
I like that scenario better than spending $300 on a Stihl that will last longer.
I figure I gan have 5 new ones over the course of 30 years with no problems and no big investment and I know the Stihl will need some form of repair in that time frame.
That's my theory though. Some people sill love their Stihl trimmers though.
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