Wednesday, April 4, 2012

Small Engine Maintenance .

 Just starting to go over my small engines . We run Stihl as much as possible here . I have been using castrol 2 cycle oil for most of the time since I've been here ( 7+ year ) Never had an issue with engines bogging down from exhaust ports clogged with carbon . Tanaka and of course Stihl are other 2 cycle oils I have been pleased with . I order filters and some parts that I know I'm going to need . A couple of hundred dollars a season for maintenance saves me a lot of grief during the summer .
 Here are a few picks taking out the fuel filters . a piece of mechanics wire to fish them out .
 When putting the new filter in make sure the line doesn't get kinked or pinched and that the filter sits on the bottom of fuel tank .
 Check the air filter or filters . Some machines have foam pr filters , they can be washed in dish soap and rinsed to reuse . The paper type filters I will use low pressure air and  blow out and if there starting to look old or are oil filled I'll replace them .
 I'm checking all the gear with pull cords and replacing the ones that I don't think will make it through season . This will prevent some of these jobs in the summer when you get busy, allowing more time for adjustments and keeping sharp edges on the mowing equipment .
If there are spark arrestors ,you can clean them with a small wire brush ( toothbrush type )and carb cleaner . If they get plugged bad the machine will idle but as soon as you hit the throttle it will just bog. In extreme cases you may have to remove exhaust and bake the carbon to dust with a torch and clean out the exhaust port on the engine .  
 I don't replace the plugs unless the edge is rounded on the bottom terminal . I'll check the gap and adjust as needed . 

Just a pick of a new plug .See the crisp edges . I'll spend some time cleaning the machines up and repairing any damages usually from old parts  . For lawn mowers I'll sharpen and balance blades . Snippers are all restringed and everything gets fresh fuel . When I put them away for the season I will mix fuel up with stabilizer and run them then dump the remaining fuel out . So far so good I Stihl have a 1995 BR 400 blower and running strong . Some of the smaller gear can get pretty pricy to replace so doing a little preventative maintenance pre and during the season can make them last a long time .
If your running the same gear year after year and sometimes a machine gets retired because of wrong fuel or for other reasons don't throw it out . Dismantle any good parts for later use . It will save you a bundle . Some small engines are cheaper to replace than to repair , I look at the cost of it new machine and at the age of the current machine if it's fairly new I may spend up to or just under half the price depending on what it is . An older model maybe a quarter of the price for a part .  If doing any major repairs price out the parts before tearing into it . It may be better off as a parts machine sometimes .

More information . 2014

Pointing out some thinks to look for when disassembling and putting snipper back together .

This is one of our older snippers pre 2003 model .Been here longer than I have . Mount shaft in vice for easier tear down. 

Back out the screw that locks engine to handle then loosen the one below it . On the trigger handle on opposite side of this picture there are 2 recessed screws that can be loosened off to release it from shaft . 

Slide it off and place on bench .

This is whats left in vice .Check bushing .

Remove the 2 screws holding the cover on .Then 2 more to remove the fuel tank . You can tell this ones old the fuel tank has yellowed quite a bit over the years . 

Check pull cord for fraying .

3 more screws removes the clutch housing .

Looking for any missing parts like springs and clips or chipped shoes . If you ever had one that works great but won't idle or runs rough then a spring may have broken on the clutch . I have seen a few of them do it . 

Check this end for worn bearings . Clean both parts with brake clean or parts cleaner and dry off . 

Air gap for coil . I don't usually check this unless the coil was replaced . If your in a pinch a match book cover makes a perfect tool for gaping the coil. loosen coil off rotate clutch ( ground wire for spark plug first )till magnet pinches the match book then snug in screws  

Check plug if it the sharp edges are worn replace plug . Check plug gap before installing .

You can get lube sticks to put on threads of plugs . I used a good contact cleaner for spark plug wire then a die electric grease on plug end . 

Reassemble clutch housing .Check to see that the rubber plugs for fuel tank are stihl in place plus the one on the pull cord housing . Check fuel lines and replace them if they feel hard also replace fuel filter every year . 

Pull the spark arrestor screen out of muffler . If it looks like this just spray some carb cleaner on it and blow off  . Screens will get plugged from old fuel ,wrong mixes , running them at idle for long periods of time . plugged screens usually involves removing the muffler ( three screws ) and torching it with a propane torch to burn out and carbon etc. Blow out afterwards . If the machine bogs from idle to run speed then most likely it's carbon up . 

Check primer bulb for leaks or cracks .screw in center of pick will take some slack out of cable . leave it slightly loose . also on top of handle the there is a slot you can slide to make more adjustments to throttle cable tension .

Line the top screw with hole , you might have to move motor in and out turning it a bit each time till the shaft lines up with clutch.

Slide handle back so wire loom sets in this spot as shown in the picture below.

Installed a new zip tie to let the staff know what fuel it takes . Clean or replace air filters . install motor housing . Fill with fresh fuel and start . Set jets if needed and idle screw so snipper head is not moving . This screw on the older ones will vibrate to full throttle . I put a dab of silicon on it to keep it in place . 

Check the line trimmer . This one was loose . 

Grease the snipper trimmer head .

Different machine . But some one ran raw gas through and scored the piston and cylinder . Even with all the systems in place to prevent this it can stihl happen .

The machine is fairly new and will repair with a new head piston assembly . Waiting for parts .


  1. That's a good information. I agree with that. sometimes replacing seems more cheaper that repair.

  2. Clicking on Ipsser will take you to a well laid out B&G parts supplier.

  3. I haven't used them before just pointing out the link.