Cub Cadet XT1 Kohler 17hp only running open choke AFTER carb replacement

dmiller · #1 10-08-2024, 02:57 PM

2018 Cub Cadet XT1, Motor is a Kohler SV541 17HP manufactured 2017

EDIT: I was having issues starting my mower and this led me down a succession of steps to the point where I can sometimes get it to start and run rough with the choke on, but it turns off when backing the choke off to normal throttle. I got 150lbs of compression when I tested it. I have done the following so far: Replace spark plug, replace ignition coil, replace carb, replace gas line tubing and fuel filter (also added fuel shut off valve). I am not sure what to do at this point. Could this be a carb linkage adjustment? Could this be bad gas even though I got gas 2 weeks ago and I store my can out of the weather? Any help is very much appreciated!

Red Dave · #2 10-08-2024, 03:26 PM

Quote:

Originally Posted by dmiller

2018 Cub Cadet XT1, Motor is a Kohler SV541 17HP manufactured 2017

I was having issues starting my mower and this led me down a succession of steps to the point where I can sometimes get it to start and run rough with the choke open, but it turns off when backing the choke off to normal throttle. I got 150lbs of compression when I tested it. I have done the following so far: Replace spark plug, replace ignition coil, replace carb, replace gas line tubing and fuel filter (also added fuel shut off valve). I am not sure what to do at this point. Could this be a carb linkage adjustment? Could this be bad gas even though I got gas 2 weeks ago and I store my can out of the weather? Any help is very much appreciated!

I'm confused. You say: "start and run rough with the choke open, but it turns off when backing the choke off to normal throttle"

When you pull the choke on, it closes the choke plate. Backing the choke off would be opening that plate. Do you mean that it will start and run rough with the choke closed? Then the engine stalls when you take the choke off, opening the choke?

Often, when an engine will start and only stay running with the choke closed, it indicates an air leak somewhere in the carburetor or intake.

spndncash · #3 10-08-2024, 03:30 PM

EDIT Red Dave and I wrote the same thing. he is a faster typist!
I assume you mean the engine only runs with the choke closed (or choke on) and then dies when open the choke (or shut the choke off).

it sounds like the parts shot gun has failed you. Based on what you have replaced I would guess bad fuel pump, or fuel pickup in the tank is clogged or partially clogged, or the intake is leaking air in to the engine - between the carb and the intake or the intake and the cylinder head - or it has a hole/crack in the intake, or carb or intake is loose, or the the gasket(s) is missing, etc.

running only on choke means you have too much air in the fuel/air ratio. so it could be many things but they are all not enough fuel or too much air.

dmiller · #4 10-08-2024, 04:01 PM

Yes, you are correct, I meant to say the choke was "ON" not open. Sorry for the confusion there... I am mechanically inclined, but not an expert with small engines, so bear with me on part and engine names. I don't think it is a fuel supply issue. It is gravity fed and I replaced the fuel line to the carb and it was flowing very easily on reassembly (as I could see fuel pouring through the new clear fuel filter). The valve cover gasket has leaked oil on this mower since almost right after I bought it, and I have a replacement, but wanted to avoid that job until I got this worked out. Not sure if this is valuable information (the oil is filled btw). The carb came with a new gasket between the carb and the engine, and I used this, but there was also a clear looking gasket that was stuck on the engine manifold that I left on there. It looked like almost cling wrap and was smooth. I could try to remove this and go with just the gasket that came with the carb, but I didn't want to remove it as it looked important. I am going to swap out the gas when I get home and take off the clear gasket that was stuck to the engine manifold. Just to be sure, when you say air leaking from the intake, do you mean the black plastic housing with the air filter in it connected to the carb?

spndncash · #5 10-08-2024, 04:27 PM

I would primarily be concerned with air leakage between the back side or underside of the carb and the engine. But, some engines need the air filter on it to run without the choke on or it runs too lean. since you said it is feeding gas and it is gravity fed, then focus on the air side.

I looked on the cub site but could not find an XT1 with a SV541 engine. they all had twin cylinder engines. I may be looking at the wrong equipment. When I googled the SV541 (this was for a MTD so it could be different) it shows as a single cylinder and it showed a fuel pump and an optional carb spacer (yours may not have this or the pump) from the drawing it looks like there is a carb, then a gasket, then a shroud, then another gasket then the cylinder head. that gasket between the shroud and the head may have fallen down.
I circled what I think you have in Red, the optional stack up is in blue and the fuel pump which you dont on yours is in fuchia

dmiller · #6 10-08-2024, 05:54 PM

Thank you for the detailed follow up. I attached a photo of my engine sticker. I did notice that it came up as MTD on some sites, but it is a Kohler. My model does not have the fuel pump, but does have the carb spacer (picture attached) I din't replace the spacer or the gasket that is between the spacer and the engine manifold. Everything seems pretty tight, but I will try to order that gasket and hope that is where there is air getting in. I also just put a new air filter in and inspected the air intake housing and don't see any cracks, deformation, or damage to the plastic housing.

ol'George · #7 10-10-2024, 07:38 AM

Hope you saved your old Carb, Factory OEM carbs, after some attention,
most always are better than SCAMAZON or CHINAAAAh knockoffs.
Some have good luck with will-fit carbs, others not so much, its a crap shoot.
If you paid big $$$ on an oem factory carb they usually are good.
You didn't mention why you decided to replace the carb, instead of cleaning and adjusting the oem one.

(some new ones are not adjustable) other than idle rpm's.