Well this is going to be pretty hard to explain, so I'll try to keep it simple and if you think you can help me I will send you more information. I'm currently working on a small project that would require a small engine. I'm pretty tight on cash (a student) so after doing some late night scavanging I found a nice old (I really mean OLD) sears and roebucks (too lazy to check the spelling) 3hp weed wacker. I took it home and took out the engine, but it won't start. I'm pretty good mechanically, but just don't know anything about small engines, so I have no idea how to fix it. After talking to some people I have found out that the firt thing to go on weed wackers is the carburetor, so I took it off, but don't know enough about it to identify the problem. If you are thinking that I should just take it to the repair shop or get another engine, they just really aren't options. I have access to a digital camera so I can get you all of the pictures you need if you think you could help. This is really important so please help me out. My AIM is Navarchy and my email address is Navarchy@AOL.com Thanks for your help.

-- Evan Sangaline (Navarchy@AOL.com), September 07, 2001

Answers

since most weed wackers are 2 cycle,, Id check the compression first,, use the "thumb technique". If thats ok,, then Check the fuel lines,, make sure its getttign fuel,,check the spark,, do the basics first.

-- stan (sopal@net-port.com), September 07, 2001.

I would first put it back together. Then take it one step at a time.

First, it needs compression, fuel and spark, assuming it's undamaged internally. If it turns over, that's good: the piston is not frozen in the cylinder. After a few pulls, use a spark-plug wrench to take out the spark plug. Pull it again. If it turns much easier then it probably has enough compression. To be sure, put your thumb over the hole (as mentioned previously) and pull the cord. If there is no pressure to speak of, you have junk. If you can see or smell gas on the plug, the carb may be ok. Connect the plug to its wire and lean the plug body on a metal part of the engine and pull the cord. (This can be tricky. One alternative: having someone hold onto the plug wire and simultaneously touching the engine, is considered justifiable homicide.) If you can see a spark or hear a snap, then the magneto etc. is ok. If not, you have a spark problem. In any case, get a new plug. Before you replace the plug pour a capful of gas-oil into the cylinder or spray a shot of starting fluid. Screw in the plug, make sure everyting is connected and then pull the cord. It should fire and start. If it does and then dies in a few seconds, you have a fuel problem.

The most likely problem is the carb. Most two-cycles have Walbro or Tillotson carbs and rebuild kits are usually available for $15-20 at shops where chain saws, week whakers, etc. are sold.

Your best bet is probably to take it to a small engine repair shop. I have paid between $15 and $30 for a carb rebuild and adjustment.

Good luck.

-- Marty Boraas (boraas@miliserv.net), September 07, 2001.

Well there is compression, and after taking the sparkplug out and trying to get it to spark I got quite a shock so it generates power and I'm not quite sure if there is gas inside. Some people have emailed me explaining lawn mower carbs and this is nothing like what they describe, it's a real oldy. I think I might however of found the problem. After my first investigation I discovered that there was no gap on the sparkplug so I bent it open and replaced it. I discovered yesterday that it was cosed again. AFter some more expermentation I found that every time the engine turns over the piston hits the sparkplug closing the gap. I am hoping that somebody had the engine and tried to replace an old sparkplug using the wrong size. When they found it didn't work they figured the whole engine was crap so they threw it away. I'm going to the store today to get a shorter sparkplug. With an engine that hasn't been started in years, I'm sure that there will be some other problems as well. I was amazed to find that the inside of the motor was amazingly clean and lurbricated (does this mean it will most likely run?). After replacing the sparkplug I'll check back with you all.

-- Evan Sanglaine (Navarchy@AOL.com), September 08, 2001.

if the piston is hitting the plug,, and its the correct size plug,,, the bearings are shot., giving the piston free play,, that little extra 1/4, 1/2 inch is enough. Find out if its the correct plug,, if so,, trash it

-- stan (sopal@net-port.com), September 08, 2001.

When dealing with an old 2-cycle, or any old clunker, junker or weekend project, it is best to do a complete overhaul. This eliminates opening the engine again and again after you have fixed one problem only to find out there is another problem. I find it easier doing the "process of elimination" approach. Test or check one thing at a time. I find it works best because all functions and parts get inspected doing this process.

Hope this will help you in future problems.

-- Joe cabrera (joec40@gtepacifica.net)

-- Joe C. Cabrera (joec40@gtepacifica.net), March 04, 2002.

by a god damn new weed wacker!

-- billy cristal (blank@blankyahoo.com), April 21, 2002.

I also have a problem with a weed wacker engine. I think it is rather new (only a few years old with not too much use). The person who had it said they put some fuel in the cylinder and it ran for a second but it won't run normally. I busted it down a bit. The plug gets spark, the ports are free, the bearings look good, It has compresson, and the carb looks pretty clean after taking as much as I could of it apart. I couldn't get to the the needle though. It should run. I have no clue.

I want to use it to make a big r/c hovercraft. :D

-- Andrew Guest (Personman_42@yahoo.com), May 11, 2002.