Engine Engine erratic

[Crushor]

Good day all, I have a problem with a Cub Cadet SLT1554. Just did the oil change and spark plug change to begin the cutting season. Fired it up and it is running erratically. In short, it is revving itself, much like a person that is revving it through the speed control lever. It is spitting gas out of the carb and backfiring at the same time. Strangely enough, this mower was functioning great when parked at the end of the season last year. The down side... It has 298 hours on the clock and has been in the shop 3 times for engine repair under warranty. It has had a lot of parts changed...pistons, rings, valve seats, etc. It has the Kohler Command engine, and honestly I've about had it with this mower. We purchased it new, and in addition to the engine repairs, it has had 3 drive belts, 2 deck belts, and a new pulley on the crankshaft. Whatever happened to quality?

In any event...does anyone have an idea on the possibility of a fix for the erratic operation of the engine. To this point, the fuel filter has a couple seasons on it, but would change it if that were the problem. Haven't gotten there yet. As always, help is most greatly appreciated.

Thank you

 

[TnHusky]

Sounds like the governor's have went bad. Single or dual cylinder?

 

[Rivets]

Two things come to mind. One, sticking float needle valve. Second, sticking valve or improperly set valve clearance. You said they replaced the valve seats? Why?

 

[DaveTN]

Since you said it was running fine when it went into storage, and now runs erratic, sputters, and backfires....it could be something as simple as bad gas, or water (they do condense water into the carb bowl, even in a garage!) in the bowl. Why not take the bowl off, see if it has bad gas, sediments, or water in it. Blow out the carburetor, move the float up and down to see if gas flows. Squirt out the main pickup tube with carb cleaner with the straw on it. Then re-assemble and see if that helps it. Can't hurt!

 

[Crushor]

Rivets, the reason for multiple times in the shop including the valve seats was that this thing had smoked for Mosquitos since it was about 20 hours old. Three trips in the shop with major work to get it to stopsmoking, it finally has...at least for now. Strangely enough, Cub is changing from Kohler engines to Kawasaki. According to the dealership this is starting in the larger mowers (tractors) now and will be going to the smaller mowers as time progresses.

Interestingly enough, while looking At different troubleshooting techniques for this, one mentioned a sticking vent on the gas cap. I took the cap off and wiggled (yes, wiggled) the vent valve, put the cap on and the engine started running smoothly. I did this procedure a couple times today, as the mower was in use for about 5 hours. It started idling erratically a couple times. I may have to see if this vent valve is a replaceable item or I may need a new gas cap. At least at this moment, that seems as what may be the problem. I just feel that for what now is 304.5 hours, there are a lot of failures on this mower.

Now for the humor in this (if you can find it)...when I went to the Cub dealer to get oil and a filter for this tractor, I informed them that this was a Super LT 1554 (SLT1554). The parts guy tried to tell me that Cub never produced an SLT 1554. It took them 45 minutes to figure out that this was in fact theirs. Gee, it's only been here 3 times for repair and you're still trying to tell me it's not a Cub...unbelievable.

 

[Crushor]

Oh, sorry... Thank you to all who responded. I apparently got on my soap box and forgot to thank you.