Export thread

Hi all, I have an older MTD yardman rototiller with a B&S model 135202 engine. Cannot get it to start, not even close. It will run for a few seconds if i spray carb cleaner or starting fluid into the carb but then quits. It has one of those carbs that mount on top of the gas tank, with a pickup tube going into the tank. So far here is what I did:

Changed spark plug { its getting a nice spark}
Pumped old gas { was a nice milky color, as it sat outside all winter} out of tank, put in fresh gas
Removed carb from tank, cleaned screen at bottom of pickup tube, can blow air thru tube and out carb opening.Sprayed carb cleaner in all holes & openings.
Diaphragm looks ok, { I don't see any holes or tears}

So when I pull the rope, it doesn't even sound like it wants to start. Compression reads at 60 psi. I'm stumped!!

Milky color means water, and where the carb sits on the tank, is also a cup/bowl that gets rusted out, and gets rust holes in it where it can't hold any gas. That may be much of your problem.

If it starts and will run on fuel/cleaner shot in the carb throat, then you know that it is a fuel problem. Compression readings are useless on most small engines, because of some form of compression release is usually used.

I did see that cup, there was rusty liquid in it so i removed it all. Now you've triggered my memory, when i screwed the carb back onto the tank, i did not fill that bowl with gas. Left it dry. Should i have filled it? Is there a way to fill it without removing the carb again?

pmgnut said:

I did see that cup, there was rusty liquid in it so i removed it all. Now you've triggered my memory, when i screwed the carb back onto the tank, i did not fill that bowl with gas. Left it dry. Should i have filled it? Is there a way to fill it without removing the carb again?

Click to expand...

It should fill itself up.

what should the diaphragm look like? Its in tact { no holes} but the position its currently in is like its sucked into the backside of the cover plate. Is that normal?

It should be changed, it is cheap. While that cover is off, blow carb spray into the little holes that the little flappers cover. If that cup is rusty, it may have some rust holes in it.

Picked up diaphragm, installed it, still no good. Doesnt even sound like it wants to start. I'm stumped, not sure what else there is to check

Milky color means water, and where the carb sits on the tank, is also a cup/bowl that gets rusted out, and gets rust holes in it where it can't hold any gas. That may be much of your problem.

I just removed the carb again, that bowl is full of fuel and not leaking.

Take off the air filter and dribble some fuel in the carb throat, and then start it. If it runs, then choke it with the choke as it starts to die, and see what happens.

Can you take a pic of the carb? To see what the mixture screw setup looks like.

Ok i will try that. Aside from that, any remote chance it could be a sheared flywheel key?

...yes will post a picture in a bit, camera battery charging

If it will run on a squirt of fuel down the carb, then die when that squirt is burned off, then it is a fuel problem.

Ok making some progress. Put carb back on after a second cleaning, this time i removed the idle mixture screw, it was really dirty. Put in back in all the way, then backed off 1 1/2 turns, it finally started up and ran longer than normal but then died. It will run for a couple minutes with 3/4 choke then stall. Did i back off the idle screw too far or too little? Where is the sweet spot?

The parts lookup showed 2 different carbs.
Can you take a pic?

Camera not working but this is what it looks like

Ok seems to be running fine now, must have been that needle valve I guess. Ran find for 5 minutes just now with choke off. Just want to be sure i have that screw set just right, not sure how many turns back i need to be.

You likely have crud in there, so to compensate, one backs the screw out more than normal.

Run it!!!

Thanks for the help!