# Troy Bilt TB25CS Trimmer



## jack13man (Apr 28, 2008)

I have a 4 or 5 year old string trimmer with the spring assisted start. It has not been run more than several hours total because something happened to the "spring assist" the first year and my neighbor gave me another trimmer just like it. I am now trying to repair this trimmer. There doesn't seem to be much tension when I pull on the starter rope and I have taken it apart down to the clutches. At this point I'm not quite sure what the Spring assist looks like or how to get the clutches off. I have looked for a IPL for this unit but cannot find one that matches my numbers TB25CS (4MTDS.0314RA.EM) Any help you could give me would be greatly appreciated. Thanks


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## jack13man (Apr 28, 2008)

ok I figured out how to remove the clutch. The spring assist start does not seem to be functioning properly. Can anyone tell me what I can check. Bot the recoil springs look good and the 2 little dogs on the flywheel seem to be ok. At this point I am at a dead end. Any help would be appreciated.


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## 30yearTech (Sep 14, 2006)

Does it not spin the engine over when the rope is pulled??


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## jack13man (Apr 28, 2008)

Yes it spins the engine but not very fast. My other trimmer you can feel the "spring assist" kick in and turn the engine over but this one the spring assist does not seem to be engaging.


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## hankster (Jan 1, 1998)

I would guess the compression is low. Pull the muffler and look for scoring on the piston/cylinder.


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## jack13man (Apr 28, 2008)

Thanks Hankster.....pulled the muffler and the cylinder does not appear to have scoring or scratches. Most of the cross checking is very visible. I checked the compression , however, and only have about 85. I would guess I need to pull the piston and further check the cylinder and rings. Is it possible that a ring is just stuck? Considering everything I have read I would suspect that poor /old gas contibuted to the problem.
This trimmer was only run several hours and everything was ok when it was put away.(it was put away with all gas still full) It has never been started after that so maybe its not as bad as I think. Thanks for the help.


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## Deathrite (May 21, 2009)

been sitting all that time with gas in the tank? suspect carb needs cleaning. replace fuel filter and carb gaskets. careful the spring under the lever. get fresh fuel from a station and put GOOD (FD rated) 2-cycle oil in to mix. 
good luck


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## hankster (Jan 1, 1998)

The spring assist starter works against the compression. The spring winds up until it can "over-power" the compression.... no/low compression, no resistance to wind up the spring. Generally those motors don't have a sticking ring problem but it is possible... only way to tell for sure is to pull the cylinder.

I was also going to suggest a sheared flywheel key but I see you were able to check the compression so it would appear that the flywheel is still attached to the crank.


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## jack13man (Apr 28, 2008)

Hankster you are correct......by the way, thanks much for the explanation of how the spring assist works.......after you suggested low compression I kind of figured it out but really appreciate the lesson...Now here is what I found when I pulled the cylinder. !st I found the rod bearing gone...of course pieces had to of gone into the cylinder and after a close inspection there were indeed grooves in the piston and the cylinder wall. At this point I am thinking this is not worth fixing and since I have another just like it I will keep it for parts. Thanks for the help. More lessons learned. ( I now use synthetic oil in my 2 strokes)


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