REPLACEMENT CARB FOR 520H

[GATOR MIKE 0]

I am getting the 520H snowplow ready for winter and I am replacing or rebuilding the carb.  It has a 146-0698 with accelerator pump on it now but the repair manual calls for a 146-0430 no pump.  Which is better for a replacement or should I just rebuild the 0698 and leave it on?  Thanks

[Ed Kennell 47,786]

 to the  Mike.      Why do you need to rebuild or replace the carb?    Mine surged badly and needed 1/2 choke to keep running.

 

I cleaned it several times and it has been running perfectly for many years.

[Handy Don 17,651]

3 hours ago, Ed Kennell said:

cleaned it several times

Yep. Same here and the last time I broke down and removed the Welch plug to clean behind it (hint, hint). 

[GATOR MIKE 0]

5 hours ago, Ed Kennell said:

 to the  Mike.      Why do you need to rebuild or replace the carb?    Mine surged badly and needed 1/2 choke to keep running.

 

I cleaned it several times and it has been running perfectly for many years.

I was getting a lot of gas in my oil.  Posts told me it could be from fuel pump diaphragm or from stuck float/needle valve in carb.  So decided to do a total rehaul - new votage reg., new coil, plugs, oil, filter and rebuild or replace carb?  Thoughts?

[sqrlgtr 4,163]

Went through my 520H a few months back. Mine surged bad but it was due to the 2pc manifold leaking where it goes together. I rebuilt carb, fixed manifold, decarbed everything and adjusted the valves (probally forgetting some stuff)  while had all the tins and stuff off. My carb was the one without the accelerator pump and everything I read about you would be better off without the accelerator pump carb so if I was going to replace your carb with another I would find one without the pump. Rebuilding mine was prety straight forward but I dont know about one with the accelrator pump. It is my understanding the carbs will swap from one to another. Here is a few pics for reference that might help ya.

[Handy Don 17,651]

26 minutes ago, GATOR MIKE said:

total rehaul

I’m too frugal to replace parts until I’m sure they’re kaput.

Yes, it is possible for a leaking fuel pump diaphragm to introduce fuel into the crankcase. Caught early, the likelihood of damage is slight. A replacement diaphragm or pump is not a difficult repair.

Oil change and new filter? Absolutely 

Voltage regulators do fail but preemptive replacement? Not something I’d do. 

Aftermarket carbs are available for the P220, but by the time you’ve removed the carb you’re most of the way toward a thorough cleaning. Unless there is internal corrosion or evidence of other irreparable damage, a cleaning with a standard rebuild kit install would be my starting point. Plenty of posts here cover being thorough, including getting under and replacing the Welch plug.

Coil? if you have spark now, no.

Plugs. Sure if it’l make you happy.

Plug wires? If there is any sign they are not doing the job then yes. 
Transaxle oil change and filter? Probably unless you know oil is in good shape and proper filter is less then 50 hours old. 

[953 nut 70,166]

18 hours ago, Handy Don said:

Yes, it is possible for a leaking fuel pump diaphragm to introduce fuel into the crankcase. Caught early, the likelihood of damage is slight. A replacement diaphragm or pump is not a difficult repair.

 

For the price of a fuel pump repair kit you could buy an electric fuel pump and never have to worry about gasoline contaminating your engine oil.   

[sqrlgtr 4,163]

I missed post #4 about the fuel pump. Your starter and electrical system will thank you if you decide to go with an electric fuel pump. One of my 520,s had the original fuel pump on it when I got it and it seemed to be a healthy one, would squirt fuel across shop, of course it took quite a few revolutions of the engine to get fuel system primed back up if it sat for any length of time. After installing electric fuel pump all I have to do is turn key on, let pump run for a second or two, and almost an instant start. I prefer the old mechanical pumps on the older WH's just for sake of being original but the electric fuel pumps are a much better fit for anything with the fuel tank below the carb and you dont have to worry about the diaphragm of a mechanical leaking fuel into the crankcase. Here is a couple pics of the one I installed on my 520.

[Ed Kennell 47,786]

22 hours ago, GATOR MIKE said:

I was getting a lot of gas in my oil.  Posts told me it could be from fuel pump diaphragm or from stuck float/needle valve in carb.  So decided to do a total rehaul - new votage reg., new coil, plugs, oil, filter and rebuild or replace carb?  Thoughts?

A leaking diaphragm in the fuel pump is probably the problem.    Replace it with an E-pump as mentioned above.    Then decide if other parts need replaced.

It is always best to replace one part at a time.    New parts are not always good and you could be installing a new problem.