thanks for the great welcome...got the belt on today...but know the tractor only runs on full ckoke ...if it bogs down when cutting or going up a hill i have to pull the choke fully out ...its a ch18s...spes no.62513 serial no.2320101847 i think as its hard to read..spraed the carb out with cleaner but did not remove main jet or idel jet or screw...will not run if choke is pushed in but backfire and pop and die ...thanks marc
Sounds like it's running lean, not getting enough fuel into the engine. If it has an adjustable main jet, back the screw out a half turn or so, and see how it runs.
The main jet may be plugged with crud, and the only effective way to clean it is to take the carb apart and clean it. Use soft wire to clean the jets and passage out. I squirt brake cleaner (carb cleaner would be better) through the passages and jets to make sure they are open. Safety glasses are mandatory, since the stuff goes everywhere.
You could have a plugged filter, clogged fuel line or tank, but I think that the engine would starve to a halt if that were the case.
i did find this...
Carburetor Adjustments (CH18-740)
In compliance with government emission standards,
the carburetor is calibrated to deliver the correct airto-
fuel mixture to the engine under all operating
conditions. The high-speed mixture is preset and
cannot be adjusted. Pre-compliance carburetors
contain a low idle fuel adjusting needle, on “certified”
compliance carburetors, both the low and high speed
mixture circuits are pre-established and cannot be
adjusted. The low idle speed (RPM) is the only
Sometimes the adjustments are there, but behind plugs. Enough said.
It sounds like you need to take the carb apart and give it a thorough cleaning. Be particular, as sometimes people have to do it 2 or 3 times to get the job done.
Note that this is assuming that you have no leaks in the intake system. Is the carb mounted tightly to the engine? Check for vacuum leaks by squirting something like WD-40 around the gasket(s), If there's a leak, the engine will run differently for a moment or two. I'd check for leaks before taking the carb apart, but odds are that a passage or jet is plugged.
i have the exact same mower/engine. mine only runs decent when at 1/2 choke. needs full choke to start and if closed completely after starting it'll die. i'm assuming mine needs cleaned, but i'm holding out till winter so i can take care of some other stuff like new tires, sandblasting and painting wheels and deck, fixing headlights....and the list goes on.
glad you got it going for now....atleast it's usable in it's current condition and hopefully a cleaning is all yours (and mine) needs.
and hopefully you downloaded the manual so you can get all sorts of usefull info....like which of those 2 pulleys the mower belt goes on and which one the blower/tiller goes on. yeah, i had the same thought when installing my deck the first time...."what the ****, why do i have 2 pulleys and what does the red and green sticker mean?". but the manual helped (and this site) so she's working now.
i do have the blower that came with tractor ...does anyone have the diagram or manual for the blower as that will be the next step...we are going to get alot of snow here in michigan this year and i want to be ready...i did chang oil, filter, fuel filter and air cleaner runs better but still have carb trouble...guess ill have to take it off to clean it ...just dont want to make it worse as iv been know to do that ...thanks for all the help so far as im learning as im going...marc