Non running 520 H how bad can it be?

[mattd860 161]

I have also bought two Onan's with the valve seat loose and that is a relatively easy and inexpensive fix.

I thought if the valve seats on these Onans came loose the engine was toast. How did/do you fix them? I've got two Onans in 520H's - that would be good info to know.

Thanks,

Bill

Larger valve seats can be pressed into the block to replace the damaged seats. It's the primary way of fixing this problem and many have had success with this method but others have had the new seats come loose again so it's not guaranteed. http://onanparts.com/index.php?main_page=product_info&cPath=1_6&products_id=14

[Wheelhorse84 87]

Any luck with getting it running? You beat me buying that beast by a day. Good luck with it.

[ericj 1,576]

i have one at napa right now getting a new valve seat put in the intake seat was out as usual but he call ed me today and said that when he went to do a valve job on the rest of the valves the exhaust on the back cylinder the valve seat was loose in it also so now instead of about $100.00 it will cost me about $ 135.00 plus gasket which will run about $ 50.00 to $ 100.00. so it is cheaper to fix than replace and should be a good running motor when done.

to replace a valve seat properly you mill the block out or try to find a replacement seat to fit your block, you get a seat a little bigger than the block than heat the block and freeze the seat then press the 2 together i forget what the interference measurement is for sure i can check and let you know if needed. my guy got a seat and milled it to fit my block. iv'e been told that by the time you find bad valve seat you are usually to big for the replacement seat sold by onan. if done right they will last along time like oem, which depends on how well you maintain your onan

eric j

[Rock farmer 41]

Any luck with getting it running? You beat me buying that beast by a day. Good luck with it.

Just won a used ignition module and coil in EBay. Got both for under $50. Hopefully their good, and will fix my problem!

Should have them in about a week.

I didn't see the ad until it was three days old. Then I hemmed and hawed for a day before I called.

That was Friday afternoon, I bought it first thing Saturday morning!

He had a lot of calls on it. Something like twenty!

Joe

[Ken B 3,116]

I hope you are able to get it running fairly easy. After she is in good running shape that tractor is going to clean up real nice! It looks to have been kept inside. I think you are going to like it, I love my 520. I'm hoping we get a decent amount of snow here in CT. tomm. and into Saturday. I really wanna put my 520 to the test pushing some heavy stuff.

[Rock farmer 41]

I won't have the ignition parts till after the storm. And I need a plow extension to be able to use my dozer blade on it!

I have a Ford/Jacobsen LGT 165 with a 42" blower but, unfortunately it's not running.

And, it's too cold to work on it!

So, this storm, like the last one, will be the responsibility of my 1949 Harry Ferguson TE-20 with chains and rear grader blade, it gets the job done!

[546cowboy 301]

Good luck with those used parts, been there and done that and had to do it again less than 6 months later. That's why I will never, never buy a used ignition module again. Hard learned lessons are a fact of life. A new ignition module runs about $80 and worth every penny.

Edited February 8, 2013 by 546cowboy

[artfull dodger 329]

I would make sure you have oil pressure. That sensor should kill the ignition if there isnt any oil pressure. Find where it attaches to the block and make sure its hooked up. I will dig out my Onan manuals on CD Rom tomorrow and look up the wiring schematic and see if it just fires the idiot light or kills the fire to protect the engine. You dont want to kill the engine if its having oil pressure problems. I plan to ditch the idiot light on mine and hook up a proper gauge. Mike

[sorekiwi 761]

The Onan in my '90 520H doesnt have an oil level engine cut off, just an idiot light.

[Rock farmer 41]

I would make sure you have oil pressure. That sensor should kill the ignition if there isnt any oil pressure. Find where it attaches to the block and make sure its hooked up. I will dig out my Onan manuals on CD Rom tomorrow and look up the wiring schematic and see if it just fires the idiot light or kills the fire to protect the engine. You dont want to kill the engine if its having oil pressure problems. I plan to ditch the idiot light on mine and hook up a proper gauge. Mike

I read the owners manual and, it says the light should blink with the key on.

When the engine starts, it will kill the ignition if a low oil pressure condition exists.

So, it's just oil pressure not oil level. Electrical tests will confirm that the circuit is not open when I get the new (used) parts in!

Joe

[artfull dodger 329]

Sounds like a plan Joe, good luck with her, keep us up to date on your progress. Mike

[Rock farmer 41]

So, the wheelhorse fiery delivered a used coil and a used ignition module to me.

I tested the coil and it tested good. I will test the ignition module next. I now have one in the tractor and one in hand. When I read the onan manual it says remove the engine from the tractor, and then remove the covers. I did not see any thing about replacing the ignition module per say. I believe I need to remove the fan cover, and, perhaps the flywheel?

I sure would be nice not to have to remove the engine from the tractor.

Joe

[sorekiwi 761]

I am fairly sure you dont have to remove the engine to do it, just remove the shroud and the flywheel and its all right there.

[546cowboy 301]

I have done it without removing the engine but it is time consuming. Just watch what you are doing and use a manual.

[ericj 1,576]

i have replaced the ignition module on the tractor with out removing the motor but did you test the module yet i would before just assuming that is bad and it is easy to check if you can't find how to do it in the manual i will try to explain it

eric j

[Torino 14]

Old Iron I love you illustrations!

[Rock farmer 41]

Update!

I installed the used coil ($30 eBay) tested for spark. Spark looked good on both cylinders.

So I buttoned everything back up. Opened the fuel shutoff valve gave it a few cranks and it fired right off!

It's in my shed, so I only ran it a few seconds. But it sounded good!

Thanks for all the help guys!

Joe

[546cowboy 301]

You lucked out there. You will love that tractor the first time you use it. There is nothing like an Onan for power and it sounds like no other.