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Sun Mar 25, 2012 3:31 pm

small engine? anyone any good at trouble shooting?

the story
i have this lawn mower that was givien to me and it is a better mower then the one i have been using. it has set for about 5 years. it was stored with no fuel in the tank. was told it run fine when it was put away and i am trying to bring it out of hibernation.

the patient
toro 6 hp briggs and stratton engine

the symptoms
i put some new fuel in the tank prime it with the primer bulb and it wont start unless i give it a shot of starting fluid and will only run if i keep giving it shots starter fluid.

what i have done as of now.....
i have pulled carb and cleaned it. also made sure that the fuel line to the carb wasnt clogged.

now what should i do next to try to get this mower running again?

btw i cleaned the carb like it was done in this video.
http://www.youtube.com/watch?v=ArCAivgAyww

Sun Mar 25, 2012 5:21 pm

Here is a suggestion for something to try....remove air filter and muffler, see if it still needs starter fluid to run. I have had engines with clogged mufflers that simply couldn't 'breathe'.

Sun Mar 25, 2012 5:39 pm

If your engine will only run with you feeding it, check first for compression. When you pull the cord, will it pull hard through all the strokes? If you don't know, pull the flywheel cover off and spin the flywheel by hand. It should bounce back. If not, no compression. Pull the breather cover off, it has the tube that goes to the carb. It also has the valve stems inside it. See whether your valves are closing when you spin the engine. If not, you have to fix that. You just pull off the head, pop the valves and put the head back on. You can get a new gasket, but I've always used the same one, and never had a problem.
If your valves are working and you have compression, let the gas sit in the carb for a day or so and clean any varnish you missed. It should start afterwards.
Good luck.

Sun Mar 25, 2012 6:07 pm

little update on this.
i replaced the plug. recleaned the carb. this time soaking it in a can of berryman chem dip.

the engine feels like it has compression when you pull the rope so i am going to investigate the other stuff you guys posted tomorrow in the daylight and see if i can get this thing running.

Sun Mar 25, 2012 8:12 pm

my in laws mower always get a clogged jet under the fuel bowl. we just spray or blow it out. obvious but just in case.

Sun Mar 25, 2012 9:41 pm

This is common, and what usually happens is a stuck float but this is number two.
Make sure the float moves freely and that the needle valve and seat are clean. If it leaks fuel, its the viton seat for the needle valve.
Re-clean the main jet and the fuel passages. One of them is plugged with varnished up fuel and your dip didn't get it.
Make sure there is free passage of fuel from the intake in the tank to the float bowl inlet.

Sun Mar 25, 2012 10:26 pm

Yank the carb off and put a Megasquirt FI system on that sucker.

Mon Mar 26, 2012 10:32 am

Some little stuff could be the culprit, dirty air cleaner or something's blocking the tiny breather holes in the gas cap, for example.

Mon Mar 26, 2012 7:13 pm

well i think i got this thing figured out. had a combo of probs going for it. gunked up carb and a weak spark. i cleaned the magento and flywheel, changed the filter and plug, cleaned the carb, and i am getting a better spark then before but it still isnt a very dark blue arc across the plug when you pull the rope compaired to my other mower. so i ordered a new magento. should be here in a few days.

Tue Mar 27, 2012 8:14 pm

so do you have a carb with a float boal or one that is mounted to the tank. if is on that is mounted to the tank there is a diagpham under the carb between the car and the tank. They get hard and need to replace. If it is one with a float bowl then something is plugged up.

Tue Mar 27, 2012 9:54 pm

Magneto failure is extremely rare, so much so that it is practically unheard of.
But it won't hurt.