I need to replace the spark plug in my BSI550 generator - what type plug and size wrench do I need? Can I get at Auto Zone

You use a spark plug wrench. There are very many spark plugs but only two common sizes of wrench.

You did not say anything about make, model or year. Go to any auto parts store and ask them to look up the plug. Then have them look up the wrench and buy it.

auto zone has a tool loner program with a break kit.

Sounds like the generator unit (sometimes called the generator head) has overheated and melted the insulation in the windings. This is the same as an electric motor "burning out", and if this is the case, then the generator is toast. If you happened to notice that the lights or fans were getting dim or slowing down before the breaker tripped (without the gas engine slowing down) then this is most likely the case and you generator is toast. But if the output just suddenly quit, then it is possible that some smaller electrical component has failed. In any case, it's not something external that you can easily reset or replace. Sorry for the bad news.

Hi and welcome to FixYa, I am Kelly

The BSI550 came in 4 model types 0, 1, 2, and 3.

Types 2 and 3 are brushless. I am assuming this is a brushless generator and the following list of parts can cause the unit to suddenly stop working.

1. Capacitor(s) This unit has _ capacitors
Usually when capacitors fail on a brushless generator you first start noticing that when there is a load introduced that voltage changes dramatically. However they can just up and quit.
2. Diode pack
3. Wiring from the capacitor to the stator is damaged.
4. The Varistor in the rotor has failed (this fails because of a short in the rotor)
5. Rotor short or open
6 Stator winding short or open.

My years of experience with brushless generators is the 2 most common failures (other than wiring that happens alot) are the Rotor and the capacitors in that order. Rotors fail out of the blue... capacitors usually do not. Take a look inside the control panel. If you notice that the bottom of the the end cap enclosure looks like someone dripped candle wax in it you most likely have a failed capacitor. I probe the capacitor(s) with one terminal removed watching for a brief spike in resistance on the meter and then it drifts to infinity EACH time the meter leads are reversed. (Good result usually). After that is is on to wiring, Rotor and stator resistance tests.

Parts:
http://www.ereplacementparts.com/images/Porter_Cable/BSI550-W_TYPE_0.pdf

Thanks for choosing FixYa,
Kelly

The Yamaha EF2500 portable generator uses a NGK spark plug #BPR6HS. Just bought on this week at the local NAPA store to replace the old spark plug in my generator.

Tom in Lafayette, IN

Hi, You need a new Spark Plugs Spark Plug Wrench Socket wrench Extension (At least 2-3 inch) size 10 socket size 12 socket...
First thing you need to do is find out where the spark plug cover is. Once you figure that out there will probably be size 10 or/and 12 bolts honding it down. Take that off and there you will see sensors connecting to each other and holding the spark plug in the cylinders. Unplug all the sensors and pull out the circular plugs holding the spark plugs down. THey might be a little tight and hard to get out so you're going to need to give it a good tug. Once you pull them out MAKE SURE YOU DONT DROP ANYTHING INTO THE CYLINDERS. You can look down into them and see the spark plugs. Get your spark plug wrench, extension, and socket wrench and stick them down in and push so that the spark plug wrench grabs them. Just simply unscrew the plugs, pull them all out, and then put the next ones in, and tighten them down. Just connect all the sensors, and put the cover back on and you're done. Pretty simple.
Take care

Instead of the auto-zone trip , take it to the dealer !

not to bad you'll need long extension, front one are there in view, the back one's remove spark plug boot (long one) and with extension you can reach spark plug's.

if its your first time you need a haynes repair manual.you need a spark plug boot puller.you need 3/8 ratchet wrench.spark plug sockets.from size 5/8 to 13/16.you probably need size 5/8 socket.you need extensions different sizes.and universal joints.to reach hard to get plugs.you need torque wrench. and spark plug gap set.

http://www.autozone.com/autozone/repairinfo/common/repairInfoMain.jsp?targetPage=productsHowToInspect&leftNavPage=productsHowTo&pageId=%090900c15280213e6e&subtitle=service
Try to copy and paste this web site. It's for Auto Zone. It will tell you all you need to know about your vehicle.
Good Luck and hope this helps.