Question about Troy Bilt Tb425cs 26cc 4 - Cycle Curved - Shaft Gas Trimmer with Ez - Start and Speed Spool

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Cub Cadet cc4125 - Worn out, excessive smoke with

Cub Cadet cc4125 - Worn out, excessive smoke with little use. Excessive 1/8"+ Compression ring end gap. Worn oil control ring (no expansion in diameter beyond piston diameter). It's easy to see how the oil easily reaches the combustion chamber from the crankcase. All other tolerances are fine. The parts list shows an entire piston and piston rings, a $35.00 + . The piston is fine - from all the oil between it and the cylinder. Where can I find a set of piston rings only? I may be behind the times and these things are relatively cheap, but it's very difficult to scrap an otherwise operable trimmer due to excessive part costs. I checked with Sears for the Craftsman version. They sell the shortblock with everything but the cylinder. Cylinder dia. =1.255". Compression rings' cross section: 0.032+ thick and 0.040" depth. Oil control rings are 0.010" x 0.040". These of course are separated by the expansion ring. The combined thickness is 0.070".

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  • Tom Bee
    Tom Bee Aug 14, 2015

    My Cub Cadet 4125 would start on starter fluid but would not run. The carb had a glob of varnish in it. I cleaned the carb out put it back together with a few skwerts of carb cleaner. It started right up. Runs great I am going to drain the fuel out from now on. store it DRY.



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It's not worth the expense and time, just purchase a new one.

Posted on Sep 02, 2016


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SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

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Posted on Jan 02, 2017

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SOURCE: excess white smoke coming from exhaust of TB 75SS string trimmer

This model is a four cycle engine meaning that it does not a mix of gas and 2 cycle oil. You just fill it like your lawn mower, gas and fill the crank case with oil

Posted on May 25, 2009

  • 323 Answers

SOURCE: Never used trimmer won't stay running.

Sometimes when they set up a long time the gas turns to something that smells like shellac and clogs up the fuel lines and the carb jets. Even though you've put in fresh gas, (1:50 ratio) the carb and lines may still be gunky. If you get it to start by spraying starter fluid in the carb, then its simply running out the starter fluid.

I would begin by replacing all the little plastic hoses from the gas tank to the carb and make sure the primer bulb is in good condition. That done, I'd take off the air filter and spray carb cleaner through it until it ran out. You'll have to crank some, without expecting it to start, but you have to get whatever is in there out.
This will mess up the spark plug, so if you have the old one, put it back in until the cleaning is done.
Press the primer bulb until you know fresh gas is coming out. When it is thoroughly cleaned, put it all back together and let it dry out.

Then try again, giving the bulb 4 or 5 hits. If it turns over on full choke and sounds as though it might run, back off the choke a little. You'll probably need to spray starter fluid in the carb until it is drawing fresh gas.
If you can't get it to run continuously, get a small screwdriver and when you get ready to start, turn the high speed adjustment a 1/4th turn to the right.
Keep trying that until it either runs or doesn't. Keep track of how many quarter turns you make. When it does start, hold the throttle wide open. If you've turned the screw to a point where it won't start at all, turn the hi speed screw back the number of turns you opened it, and then turn it all the way closed, counting the number of turns from where it originally was. After closing it, try a starting point at about 2.5 turns open. Once you get it started at wide open throttle, you have to play with the high speed screw, turning it first open, listening to the sound of the engine. If it starts to sound smoother, continue until it starts to stutter, then go back 1/2 turn. If it doesn't start, or sounds worse when you open it, turn back closed until it smooths out. Once started and it keeps running, run it long enough to get everything burned out.

To get it started easily after the hi speed is ok, then play with the low speed the same way. I would start by closing it (left) and counting the turns. Then go back to that point and open 1/2 turn. Do that until it either starts easily or is obvious it won't start and run well at low speed. Then go the other way.

It takes a while, but it will be worth it once you get it running. If all else fails, you can buy a new carb online for probably $30.
Good Luck!


Posted on Jun 01, 2009

  • 1584 Answers

SOURCE: Trimmer dosen't start.

When you gapped module did you set it to Manufacturers spec.....extremely important, also supposed to use brass feeler blades to gap. Gap is usually 0.010" inch. Also ensure that the flywheel magnets are NOT rusty.

Timing will alter if flywheel key is worn.

Is fuel getting through as the carby has a fuel pump diaphragm in it also.

Have you trieds pulling choke when it splutters, will ID fuel stravation??

Posted on Jan 08, 2010

  • 3740 Answers

SOURCE: Trimmer is producing alot of

This engine does NOT used mixed gas at all! It uses straight unleaded gas. If your using mixed fuel of any mixture ratio in the engine it is really going to smoke badly. What fuel are you using please?

Posted on Jul 02, 2011

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My 2011 Kia Cerato "S" has been using a lot of oil. The cylinder head was re-conditioned and engine serviced. The now engine blows smoke every time on starting. What is the probable cause ?

depends on how the head was reconditioned
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not necessarily
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There fore it stands to reason that if you have worn rings/ broken ring or cylinder scored then there will be excess compression gas to the sump which tends to boil off the oil or actually burn the oil fumes in the sump and this excessive smoke will find its way back into the inlet manifold and if too much ,out the exhaust as smoke
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I suggest that you have a compression test done to gauge the condition of the engine, an oil pressure test done with a mechanical gauge to measure the oil pressure to determine the condition of the bearings as excessive bearing clearance will overload the weak oil rings and that will also cause smoke out the exhaust
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I have the Cub Cadet CC4125. The head for the line is very wasteful.Line will not stay in the spool. I also have Toro with the spool type head on it,and this is more efficicnt. Does Cub Cadet have a spool...

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I have a Cub Cadet cc4125 string trimmer not starting

need a little more information .. but look for the following .. take out the spark plug and look inside with a flashlight ... if the piston is moving with the rotation of the flywheel then you likely have a blown head gasket .. if there is no compression there wont be a load on the pull cord .. a cracked or damaged piston can also do this .. ... if the piston is not moving when you rotate the flywheel then you likely have a bad "shear key" sometimes called a "shear pin" .. thats usually a half moon shaped small metal part that keeps the flywheel locked rotationally to the crankshaft .. it is designed to shear off if there is an excessive sudden load on the engine .. the flywheel will then spin without turning the crankshaft .. the same thing will happen if you have broken the connecting rod .. (a rod failure is often preceded by lots of clatter from the engine) .. the head gasket or shear key are much more likely to be your problem .. if you cant see in the spark plug hole you might try using a straw to feel the piston motion .. its possible that without the spark plug in place the piston might move even with a bad shear pin .. because with no compression the piston will move freely .. if thats the case you can stop the piston motion with a wood dowell thru the spark plug hole .. if it moves in spite of your dowell resistance then consider the head gasket option ..

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