The 18hp Yard-Man Trailmower

Well for that style carb the high throttle mixture screw is on the bottom of the float bowl. If is running a wee bit rich you wanna turn it in like youre tightening it. Just a little bit though, too much and it will be running too lean. Also when you adjust the high idle screw you should rev the engine a few times to see if it will still rev up smoothly, and run it at WOT to see if it is misfiring or having trouble running. Just a slight adjustment should necessary to fix the smoke problem. That is if its fuel smoke.

If its bluish, you probably have some oil burning problems. or it could be your PCV breather. the actual plate thingamajigger. ive had to replace one of those before and it was the same symptoms you are experiencing. For you it seems like it could stand for some adjusting though. ya really just gotta play with the screw and find what works best. i know i spent 3 hours trying to find the sweet spot on the 12 horse on CQs simplicity.
Does the engine have good compression?
Spark plug covered in carbon/ oil/ other debris?
If your spark plug is really grody, your combustion chamber is probably the same way, along with the valves and the ports. i would recommend starting with adjusting the carb, check the pcv breather, check the spark plug, take off your carb and muffler and check the ports, and if the plug and ports are nasty, take your head off and wire wheel it with a dremel and maybe even do some porting with the dremel. Do it in that order too. i always check the little and easy stuff before i dive into ripping the head off lol

Yeah I agree with TheGreenHornet about the oil problems. If is it the oil burning it could be the PCV, sometimes you can soak them in gas for a while and it kinda cleans them out and what not. But I would try adjusting the high throttle screw first because it sounds like fuel smoke to me.

cool. i didnt know you could soak em in gas. i just keep a whole bunch of spares around. i probably have 15 of those little suckers, all different sizes from engines ive thrown out over the years. they dont die like that very often. at least they havent for me.

Usually you can tell by the smell. If its gas it will smell like a mix of carbon and fuel.

TheGreenHornet wrote:

cool. i didnt know you could soak em in gas. i just keep a whole bunch of spares around. i probably have 15 of those little suckers, all different sizes from engines ive thrown out over the years. they dont die like that very often. at least they havent for me.

Yeah I did that to the one on the MTD because the reed was kinda stuck and it wasn't working properly. I just soaked 'er in some gasoline and it cured it!

Those B&S Flatheads always smoke a wee bit. It's just part of their character I have a fairly new I/C Quiet 12.5hp (2001 I think) and it smokes a bit when you let the throttle off.

yep adjusting the carb seems to have made it much better and the spark plug is clean and the oil level never dropped so i think its gas related. it also has good compression. ill finish adjusting the carb because its dark and it was hard to seet he smoke.

It wont burn oil that fast, just a little will blacken exhaust.

Doug Fackler wrote:

It wont burn oil that fast, just a little will blacken exhaust.

oh ok

ill check the pcv thing tommorow cuz it still smokes...

Yeah well if the spark plug is clean then it probably isn't burning oil. Seeing as it isn't the original carb for the engine, it probably is still out of adjustment. Btw, are you sure there isn't oil in the gas? That causes bluish black smoke.

no theres no oil in the gas when i hoocked up the gas tank it was empty and i filled it up with fresh gas. i havent had time to check the pcv but ill do that tommorow.

u had al;ot of fun with this thing today, but i really need to get my straith axle to lock it, i do want to put a bigger pulley on the engine. maybe this week ill get a 7 in for the front.
firt and second gear a pretty much useless.

What size is on the front at the moment? I plan on running a 5 1/2 on the front and a 4" rear on my Westwood. Hoping for about 20mph.

Also, how well does the brake lever work?

at this time im running a 1:1 setup 6inch frond an rear it does a little less than 20 mph.

i want to put a 7inch in the front and keep the 6 in the rear to get a little more speed.

the brake lever work very well i still havent done the spring return but it works very well, you do have to pull it hard to lock the rear wheels but its possible.


hopefully this week im to be able to order the parts to lock my trans but im not sure, also i may go on a romp this weekend ill see.

Ah right. The reason the braking power is not that strong is probably because the pads are worn. How are you planning on locking the trans?

MatthewD wrote:

Ah right. The reason the braking power is not that strong is probably because the pads are worn. How are you planning on locking the trans?

doc locking style, straight axle.

Nice. Gonna get new tires?

MatthewD wrote:

Nice. Gonna get new tires?

maybe when ill have the money. probably used but idk yet.

sadeoo7 wrote:

MatthewD wrote:

Nice. Gonna get new tires?

maybe when ill have the money. probably used but idk yet.

I got them pretty cheap from Wal-Mart's online store. Duro 22x11-8 knobbies. There were others, but these were what I liked and they were $40 each

sadeoo7 wrote:

the brake lever work very well i still havent done the spring return but it works very well, you do have to pull it hard to lock the rear wheels but its possible.

MatthewD wrote:

Ah right. The reason the braking power is not that strong is probably because the pads are worn. How are you planning on locking the trans?

Could be a leverage issue too. I had similar issues when I had a dash set up.

i think something is binding in my brake linkage because i can feel a ''clunk'' when i pull it hard enought and the it lock the wheels, ill have to check that but hey it works so its good enought for now. ill have to take the trans out soon so ill fix that then.

something binding or it might be catching on something. id check that out. Im sure you dont want any unnecessary wear on the brakes, since they are kinda important.

TheGreenHornet wrote:

something binding or it might be catching on something. id check that out. Im sure you dont want any unnecessary wear on the brakes, since they are kinda important.

ya brakes are important. especially when you go fast haha, no its not catching on anything. ill check that soon for sure tho.

It could be binding where the linkage meets the arm, either on the brake/trans or your lever.

i got the transaxle out today. ill lock it probably fozzy lock for now. until i get the money to get a straight axle. i also want to convert my trans from grease filled to oilfilled. ill post pictures tommorow. tommorow i need to clean up the inside of the trans i checked all the bearing and the bushing and they seem good. but theres water inside the trans.