520 problems

[Ralph S 342]

I have a 520 that wants to shut down once it gets warmed up. At first it would run for 10-15 minutes then shut down like the key was turned off. It would start back up right away. It kept doing the same for a while but got harder to start. It almost seemed as if the coil would get hot then quit.and it seemed as though the fuel pump wasnt keeping up with the engine either. it would fill the filter up sporaticaly. I replaced the coil and fuel pump with brand new parts, It fired up instantly and ran for about 45 minutes then died on me. It wont start on gasoline now but will fire with a shot of go go juice. Does anybody have any clue to solve the problem or have any clue to why this beast is acting up ? my next guess is to tear apart the carburator to thoroughly clean the jets out. Another mistery is that I noticed a small amout of oil splashed or sprayed on the engine cover behind the fuel pump. Somebody give me a direction or hunch to try and get my baby working again, please.

[R Scheer 505]

I'd try disconnecting the fuel hose from the carb and cranking the motor, you should see fuel spurting from the hose.  Ie make sure that the fuel pump/fuel line/tank shutoff are all good and not plugged.

[Bill D 2,281]

Check and clean the 9 pin connector connections.  Did you change the pulse line from the crank case to the fuel pump?  It could be dried out and cracked, which would explain the oil.  When the engine is running wide open the fuel filter will tend to look only half full.  You may also need to change the crank trigger.  Jack's small engine had the best price I've seen for them.  Bill

[Ralph S 342]

7 minutes ago, R Scheer said:

I'd try disconnecting the fuel hose from the carb and cranking the motor, you should see fuel spurting from the hose.  Ie make sure that the fuel pump/fuel line/tank shutoff are all good and not plugged.

I've done all that and Im wondering if the float vave is being held closed. The shut off valve is brand new as well as the fuel lines. I have fuel getting up to the carb but seems like it isnt entering the carb. When I pull the fuel line it has pressure in it and spurts gas out. I blew air through the line to the carb and it hisses out. 5 psi of air not 90 psi. 

[Ralph S 342]

2 minutes ago, Bill D said:

Check and clean the 9 pin connector connections.  Did you change the pulse line from the crank case to the fuel pump?  It could be dried out and cracked, which would explain the oil.  When the engine is running wide open the fuel filter will tend to look only half full.  You may also need to change the crank trigger.  Jack's small engine had the best price I've seen for them.  Bill

how do i get to the pulse line without removing the engine from the frame ? Is there an easy way to do that ?

[Ralph S 342]

Just now, Ralph S said:

how do i get to the pulse line without removing the engine from the frame ? Is there an easy way to do that ?

 

[Bill D 2,281]

Pull the coil out and look down in the hole.  You should see where the line connects to the crankcase.  You should be able to reach the clamp with a long pair of pliers.  Also check your fuse block for a melted fuse holder that could be causing problems.  If you want, PM me your phone number and I will call you.  Bill

[Ralph S 342]

12 minutes ago, Bill D said:

Pull the coil out and look down in the hole.  You should see where the line connects to the crankcase.  You should be able to reach the clamp with a long pair of pliers.  Also check your fuse block for a melted fuse holder that could be causing problems.  If you want, PM me your phone number and I will call you.  Bill

Message sent. thanks

 

[cafoose 3,456]

I had similar problems with my 520 and I replaced the ignition module under the flywheel. Problem solved

 

 

[lynnmor 7,858]

I think cafoose has the correct answer.  When the module heats up it fails.  If you could quickly check for spark when the engine dies, that would be a sure sign, but I do mean quick before the module looses even a few degrees of heat.  Of course there may be other problems, but proving a spark failure narrows it down.

[EricF 589]

I'm also with @cafoose on this -- the ignition module is a likely suspect. I had a similar problem with a motorcycle engine which used solid state ignition coils. They'd heat up, and a hairline crack in the windings would expand -- No spark. When the engine cooled, the contraction made electrical contact again and presto -- spark!

[Ralph S 342]

I'll have to get that module on order.

[Ralph S 342]

Thanks guys !

[Ralph S 342]

Well It turned out that I replaced the Coil, Fuel petcock Again and the fuel pimp pulse hose. Now itll run for hours but now it wont idle propperly. LOL the fun we have messing with these things ! I'm pretty sure I hooked the governor spring up to the wrong hole in the linkage but thats an easy fix.