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Greg Cuetara
07-27-2010, 9:27 PM
I have a John Deere 111 lawn tractor. It is 1980's vintage. I bought it about 5 years ago and have had decent luck with it in the beginning. I have had electrical problems over the past few years and had to replace a number of parts. I have almost taken the whole thing apart and rebuilt it but who knows If I know what I am doing.

I have always had a really hard time starting her up but once she got going the engine came to life and was fairly strong. The coil does not back charge the battery so I have to charge the battery every time I want to use it and then typically I have to jump it to get it started. This spring I pulled it out of storage and everything had a nice coat of rust on it...so somehow I did not store it properly for the winter. Anywho, when I did get it going this spring the tractor has seemed to lose all of it's power. I thought it was a carb issue and I was able to buy another JD 111 which the engine had blown for fairly cheap. I needed some other parts so it worked out well to pick up the whole thing. I pulled the carb off the blown engine tractor and cleaned it up and put it on mine but I don't know what is going on right now.

It seems that the engine has very high rpm's but no power at all. Also whenever I go over a bump the engine almost dies so I have to stop and let the engine rpm's build back up before i keep going. Going downhill everything seems to be ok but when I turn around and come back up the hill I have to slow down and go like a snail in order to get up the hill with the pto on. I found a manual for the carb and I have tried to adjust it but I really have no clue what I am doing or what I should be looking at or for right now.

Is the idle adjustment typically on the carb? Do I just play with the jets to get that tuned up? I can post a few pictures of the carb if that is of any help.

Thanks for any advice anyone can give.

Greg

David G Baker
07-27-2010, 9:40 PM
Greg,
At the end of the mowing season drain or run all of the gas out of the lawn mower. If you store it with fuel in it add Stabil or one of the other fuel preservers. I use a product called Sea Foam that I buy from Napa Auto Parts and it works the best of any other product I have tried. You can add Sea Foam to your fuel tank and it should dissolve the shellac in the fuel system caused by gas that has sat all Winter. The evaporated fuel could be causing your problem.
This may not be your problem but it seems to solve my carb problems when they occurred.

Jim Koepke
07-28-2010, 12:36 AM
I don't think a carb problem relates to a power problem.

I recall what a co-worker once said about gasoline engines one time, "there are three things that the engine needs, fuel, ignition, compression."

It sounds like you are getting the fuel and the ignition. Your ignition timing could be wrong and might cause such a problem. If not...

That leaves compression. Do you have a way to check your compression?

You could have valves that are not opening and closing properly. You could have rings that are not seating properly.

jim

Dan Hintz
07-28-2010, 7:30 AM
I'm always amazed at how an improperly gapped sparkplug can allow an engine to run but prevent it from having any real power.

Chris Harry
07-28-2010, 8:04 AM
Engine almost dies going over a bump, power goes up when going downhill.....to me that almost sounds like a float issue in the carb, and/or the carb is set too lean.

The float "floats" on the fuel in the carb bowl.....when the fuel gets low the float lowers and opens the inlet needle letting more fuel in. Basically it keeps the fuel level constant in the bowl. It can be sticking, there can be a hole in it, etc.

Too high RPMs and no power could also be a lean condition (BAD!!) Thats what the needle setting(s) on the carb are for. But if the carb is gummed up inside the needle settings might not have any effect. Next time you have it running shoot some Sea Foam Deep Creep (can buy it at Pep Boys, AutoZone, etc) cleaner down the carb throat (take off the air cleaner and fire it in). When the engine sounds like it wants to stall, stop spraying. Repeat 3 or 4 times. That should help at least clean some stuff out of the carb (exhaust will get smoky so do it in an open area)

I suppose another possibility is a slipping transaxle/clutch/drive belt. Downhill wouldnt be an issue because you arent putting much stress on the drive, so a slipping belt might not show up. It would definitely show up going uphill though.

Jeff Monson
07-28-2010, 8:51 AM
It sounds like the engine is running too lean, I'm almost positive there is no governor on a 111, it uses a butterfly flap in the carb with spring pressure to control air flow, thus too much air and too little fuel will cause high rpm and low power. The carb is very simple on this engine, I think if you took it off and cleaned it out, you would find the problem. Make sure the mixture screw is adjusted properly also, a good starting point (engine idling, turn screw counterclockwise until it starts to surge, then 1/2 turn clockwise) that should get you in the ballpark. Also if the bushings in the butterfly valve are worn and loose you will need to address this as you are getting unmetered air, it will never tune when these are loose.

Greg Cuetara
07-28-2010, 11:18 AM
Thanks guys. I am fairly certain the carb is clean right now. I really think everything is not adjusted properly.

I will try adjusting the mixture screw like Jeff said. Not sure which screw it is though. There is one screw on the top that I can adjust and one on the bottom which goes into the float that I can adjust.

Greg