MTD Yard man w/ 18 HP Briggs and Stratton twin 2 won't stay running

[dakotanut]

I have this riding mower that I am trying to fix. The choke linkage broke and I sort of fixed it for awhile. Doesn't explain the bad idle or dieing problem. I can get it started and run it for about 5 to 10 mins or so maybe longer and then it will start to act like it is dieing and when i push the throttle to slow it will run for awhile. Then it will start acting up all over again. If I reach up and grab the trottle arm on the carb and pull it so it revs up it will last awhile and start all over again. I've cleaned the carb and it still acts up. I can start it now with out the choke though. I'm not sure about the linkage from the motor to carb. It doesn't seem to be right cause it barely moves and not freely. Thanks for any help. It is killing me.

 

[Rednekdaddy]

Have you tried changing the fuel filter?

 

[Lawnranger]

An engine needs three factors present and in the correct proportion to start and run properly - the correct air/fuel ratio (fresh, quality fuel is a must), sufficient compression (arguably 90 P.S.I. or better) and sufficient spark at the correct time. If one of these factors is missing or out of proportion, the engine will run poorly or not start/run at all. Your task is to find the missing factor by inspecting and testing the systems involved. Which factor is missing or out of proportion in your case?

If you do not know how to check for spark or perform the necessary checks and tests, youtube has some videos that will guide you through the process. Simply search youtube for what you want to test or check.

My method of testing for lack of fuel is to spray a shot of carburetor cleaner directly into the carburetor (air filter removed). When the engine starts to act up start spraying short blasts of CC in the carburetor and see if you can keep the engine running. If so, you have a fuel problem and the carburetor is most likely in need of cleaning.

 

[Carscw]

You can go to MTDPARTS.com and look up your model and you can see just how the linkage goes.

Sent from my iPhone using LMF

 

[dakotanut]

I did replace the fuel filter. It had the same problem. So, I put the old one back on. I'm going to put the new one back on today. I'm starting to think that it isn't charging the battery. It runs for awhile and then dies kinda like a vehicle when the alternator goes dead. Have to jump it and then mow for awhile and it will die again. I cleaned the carb real well. I found grass in some of the fuel tubes inside. I couldn't believe that. There is a screw on the carb below the fuel pump that is a mixture adjustment I think. I read some place to move it out 1 1/2 turns. Then other places it says not to mess with it. It was all the way in when I took a look at it. I know on mine that if the air cleaner isn't on it won't run correctly. Not sure about this one. Mine is Khoeler. I mowed without the filter on so I could see if it was losing fuel. I did notice that it's not a spray of fuel. It's more like a spitting of fuel into the manifold. I'm pretty new to riding lawnmowers. Not sure what keeps battery charged. I also found the choke part so I have to replace that. Even though I don't need the choke to start it. Thanks very much for the help.

 

[Carscw]

If you have a volt meter you can cheek to see if it is charging. With engine running at full rpm hook volt Meter to battery should show around 14.5 volts but not less than 13.

Sent from my iPhone using LMF

 

[dakotanut]

Like an automobile. Figures. Is there an alternator on this thing or is it off of the magneto? Do I need to pull the cover on the motor to find it? I take it by your post that it does have some way to charge the battery. I'm fixing to go work on it now. Again?!. :frown:

 

[dakotanut]

Ok after further testing of the battery/charging system I have found out that I'm only getting 12.61 volts max at the battery. That is with it running and me giving it all the gas it's got. Still not sure how it charges the battery though. I'm stumped. After starting it I only have 12.1 to 12.2 volts. Doesn't seem to charge to me at all. I put a battery charger on it and then it changed.

 

[dakotanut]

Found the service manual for the engine. Wish me luck.

 

[dakotanut]

I'm sorry to be such a pain to yall. I took the carb apart and cleaned it real good this time. Checked the fuel lines and tank. Replaced the fuel filter again. Started it up and checked the alternator. I have DC and AC voltage coming from it according to the manuals test procedures. So, I know that the battery is being charged. It may just be bad. Didn't have time to check. So, I'm mowing and it seems to be doing good. I get into the ditch and it starts to bog down again. OH! Did I mention that one of the valve springs in the fuel pump is missing on the carb. Yeah loved that. Can't find one in my stash. Also the needle on the float fell between the garage foundation and the drive way. I got it out. If I take the throttle lever and put it into low then it won't die. If I pull it to high it will mow for a bit and die again or try when I put it back in to low. Also, I noticed that it really doesn't control the speed. Hi or low it's about the same. I'm not sure if the missing spring in the fuel pump is the problem or not. I'm very sure it isn't helping the situation at all. I also found that the belt for the clutch is in pretty bad shape. So I'm going to replace it very soon. I don't understand the govenor stuff on the side of the engine. Seems to me it's back wards but when I compare it to the drawings in the the manual it looks ok. Don't know if it is working or not correctly. Doesn't seem to be due to when it hits some high grass it bogs or tries to die. I really appreciate any and all help yall give me. Seems that nothing is working. Thanks very much.