QuestionI cleaned with carb cleaner, all passages are clear. I reinstalled and same problem. I was able to use the choke to get it to smooth out (at least it got better).
There are no HIGH or LOW speed needle screws to adjust mixture on this NikkI Carb. Just Idle RPM adjustment.
Do you have any other ideas before I replace carb.
This is a 1997 CubCadet (MTD) model 2155 with Kohler Commando OHV 15.5HP
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Followup To
Question -
Cub circa 1997 (MTD) Kohler horizontal OHV 15.5hp
Always ran great, spring 2005 I put in a generic electrical fuel pump, pressure is likely high for a lawn mower but it ran great last year and this spring. Recently it will no longer run at high speed eventually dies. Pops and misses at high speed and under load. Motor has 500 hours on it. It runs at idle just fine, if you advance the throttle slowly it will run at high speed with no load. If you advance it quickly it pops. It will run at idle with a load (mower engaged) on it.
I replaced the plug, air filter, battery is new this spring; I have disconnect the elec fuel pump so line pressure is reduced (I just connect supply wire enough to fill inline filter bowl. This makes no difference. SO I do not believe its getting too much gas, besides it idles fine forever even with elec pump running 100%.
I disconnected the Gas line at the Carb and ran pump - getting plenty of fuel. I took off the carb and torn it down and inspected. It was clean did not replace anything but seat seemed fine and worked ok.
It almost seems like a timing issue. Does this engine have points?
I'm out of ideas. Help.
Answer -
Hello Jim:
It Sounds like a Carburator Problem. Not enough Gas being Pulled through the Primary(main) Jet. Gas turns to Varnish and Cloggs the Ports and Passages Inside the Carburator and this Restricts the Gas Flow to the Engine. The Varnish is Hard to see because it is Clear. Send me the Model Numbers of the Engine and I can Look up the Engine in my Manuals and Determine weither it has Point Set, Magnetron Ignition or Ignition Module. The Timing of the Engine is Set by the Flywheel Key. Most times if the Key is Damaged, it wont Start at All or it Pops and Misses even Idling. I Suggest you Soak the Carburator Overnight in Cleaning Solution and Rebuild it. Hope this Helps. Let me know what Happens, Please.
Good Luck
Respectfully
John
Answer Hello Jim:
You have the Throw Away Carburator. No Adjustments and No way to Repair it if the Overhaul Doesnt Work. Sorry. Check the Float for Sticking. After your last email and this One I think thats the Area your Problem is in. If the Engine is Smoking Black Smoke then the Float has Stuck Open. With the Engine Running Tap LIGHTLY on the Carburator Bowl. Does the Engine Run Differently after Doing this? The Float Should be Level with the Bowl Seat When the Carbutrator is Turned Upside Down. Hope this Helps More. Let me know what Happens, Please.
Good Luck
Respectfully
John
