Cub Cadet GT 1554 loosing compression

[meri0809]

So here is my question to all the Kohler techies out there. I have a Cub Cadet GT1554 with a Kohler KT745. Engine is about 18 months old and has less than 30 hours on it. At this point, the engine seems to be loosing compression. The linkage has been adjusted and that helped. I am thinking it is likely the valves. This year I have replaced the starter, starter solenoid, pulled the fuel solenoid (cleaned and replaced), replaced the iginition switch, replaced all the tranny pulleys, deck and tranny belts, all three mandibles, blades and plugs and gas cap. I put Berryman's B12 in the gas tank to keep the fuel system clean. Outside of the valves what would cause the engine to loose compression? Can anyone tell me what a valve job would run? I don't know if I want to sink any more money into this machine. Thanks in advance for any suggestions.

 

[ILENGINE]

What is it actually doing to make you think it is loosing compression.

 

[meri0809]

Before the linkage was adjusted, when I push the throttle up past 1/3 the engine bogs down and will cut out if I don't push the throttle back down. This is on fairly flat surface.

 

[hlw49]

I did not know a lawn mower had Mandibles. The term "mandible" refers to the jaw, specifically the lower jaw that consists of a single bone or fused bones. It is the largest and strongest bone in the skull, responsible for holding the lower teeth and facilitating chewing. In addition to its role in humans, the term can also refer to similar structures in other vertebrates and in arthropods, where it describes mouthpart appendages used for biting. LOL

 

[meri0809]

oops is mandrel...my bad.. It's the spindle that holds the blade on the deck. The deck has three blades, hence three mandrels

 

[sgkent]

lots of parts into a 30 hour mower. Is this something that developed, or something that drove all these parts being replaced? My suggestion is that you put a compression gauge on it to see how it is before assuming that the compression has failed. Probably not the problem, but something as simple as mud daubers partially plugging an exhaust with nests can slow an engine down too. A slipping belt can make it seem an engine is bogging. The parts cannon approach rarely hits the target the the first couple tries. It can make things worse too.

 

[meri0809]

The mower is circa 2006. The new engine, KT 745 from Kohler, was professionly installed in December 2023, so the tranny work was just normal maintenance. I had problems with it a couple months ago, no start, just clicked which is what caused me to replace the starter etc. No mud daubers or anything clogging the exhaust. The mower is usually stored in my garage or covered in the barn. The tranny work, pulleys, belts, mandrels, etc were all done professionally. I don't have the level of experience to muck with engines or trannys.

 

[ChrisBFRPKY]

Ah, pull the blower housing and check to see if your engine has those weird spark advance coils. It's been awhile but I think the connectors that plug into the coils will have 3 prongs and a handful of wires in each connector. If you have those coils, order the upgrade kit and swap them out with two new true magneto coils. The kit is like $30 online and includes the instructions. I know there's gotta be a ton of videos on swapping out those coils on youtube because those things are horrible.

 

[Auto Doc's]

Sounds like one ignition coil is not functioning properly, or a spark plug is bad. You are running on only one cylinder for power. V-twin engines do not shake or vibrate when a cylinder is not firing.

Simple test: Start the engine and get it hot, then use a spray bottle to shoot a stream of water on each exhaust outlet pipe on the head at the bottom. Water should burn off immediately if the cylinder is producing power. If one is slow to burn off the water, that is the side to look closer at.

If you are not mechanically inclined, then it's time to get someone who is. At least you can give them a basic starting point by this simple water test check.

At 30 hours on this new engine, it should not need any kind of valve adjustment.

 

[StarTech]

The way AI infiltrating the industry I wouldn't put it pass the design having mandibles now days. But yes the spindles assembles should have been just rebuilt instead of replacement; unless, are damaged or was removed from the deck as their mounting screws tend to break off. That would had been a couple 6204-2RS bearings for each spindle.

Since you admit you experience level is lacking I would suggest getting some help on the problem. Some problems requires hands on diagnostics.