520-H Fuel Related Issue

[clueless 2,898]

Years ago I was out in the snow while visiting my sister in Maryland, won't make that mistake again! 

[608KEB 794]

Tried to finish snow plowing. The 520H  died again. This time, new fuel line, filter, carburetor cleaned.  The float floats. The fuel pump pumps gas. To be continued 

[WVHillbilly520H 10,369]

@608KEB,Are you getting good spark, hopefully it's not the ignition module/coil, check the safety switches and wiring connections for corrosion/tightness, seems like those gremlins only show up when you really need your rigs working,Jeff

[T-Mo-(Moderator) 4,337]

Clogged gas cap?

[608KEB 794]

5 hours ago, WVHillbilly520H said:

@608KEB,Are you getting good spark, hopefully it's not the ignition module/coil, check the safety switches and wiring connections for corrosion/tightness, seems like those gremlins only show up when you really need your rigs working,Jeff

It runs for to 5-10 minutes when I'm using it. Then I have to use the choke to start it. If I let it without moving it.  It will not quit. Keeps running. I'll check the gas cap  too.

Edited December 20, 2016 by 608KEB

[cleat 4,936]

Well that sounds like fuel issues.

 

You have cleaned the carb and fuel tank.

 

You also said the pump is pumping fuel but is it pumping enough ?

 

Two of my 520's were doing that with clean carbs. One ended up being a weak fuel pump (one defective check valve), and the other one ended up being the fuel line resting against the oil filter heating it up and causing vapour lock.

 

Cleat

[608KEB 794]

44 minutes ago, cleat said:

Well that sounds like fuel issues.

 

You have cleaned the carb and fuel tank.

 

You also said the pump is pumping fuel but is it pumping enough ?

 

Two of my 520's were doing that with clean carbs. One ended up being a weak fuel pump (one defective check valve), and the other one ended up being the fuel line resting against the oil filter heating it up and causing vapour lock.

 

Cleat

Gas was flowing out good. The new fuel line is not close to the oil filter. The jet has been soaking in carburetor  cleaner. I'm  seeing  lots of black spects. Hopefully this is the problem.

Edited December 20, 2016 by 608KEB

[WVHillbilly520H 10,369]

I had the "black specks" too a while back, it's the old fuel line broken down you'll have to pull the whole carb and soak it, those rubber particles get in every little passage in there, after I did that has ran fine for the last couple years,Jeff.

[608KEB 794]

8 hours ago, WVHillbilly520H said:

I had the "black specks" too a while back, it's the old fuel line broken down you'll have to pull the whole carb and soak it, those rubber particles get in every little passage in there, after I did that has ran fine for the last couple years,Jeff.

It ran fine for about 15 minutes. Then it died. It will run between 1200-2000 rpm's with the choke on wide open. I thought I was  outta the woods with this.

Edited December 20, 2016 by 608KEB

[gt4 196]

1 hour ago, 608KEB said:

It ran fine for about 15 minutes. Then it died. It will run between 1200-2000 rpm's with the choke on wide open. 

Well i hope you find out what the cause is,as that's a really nice looking machine to have fun and work with.

[JERSEYHAWG / Glenn 4,487]

With that black particle comment I am with Jeff on the fuel lines breaking down. On all my machines it's the first thing I replace front to back. Good luck, keep us posted.

 

Glenn

[Sarge 3,462]

Go to an ATV or snowmobile dealership and get the appropriate new style fuel line - it should be either blue or yellow . That new line will not break down like rubber - the oxygenated and corn alcohol fuels today will eat rubber fuel lines - hence your black debris showing up . I'd bet you'll have to at least clean very well or rebuild the fuel pump and get those lines off of there - I do not use rubber at all anymore due to this issue . ATV companies are refusing to warranty engines now that have been fed Ethanol fuels due to burning up pistons and valve systems so it's recommended to never use Ethanol blended fuel in any small engine , especially air cooled ones .

Just an fyi , I hate the expense of non-Ethanol fuel here in the Midwest corn belt since it can be a pain to find and usually costs $.75+ more per gallon , but worth it in the long run and the engines do run better anyway . Biggest issue is the ethanol drawing water into the fuel from the atmosphere vent , later to cause freezing problems . I run all mine on Philipp's 66 - 91 octane non-ethanol (91 is all they have) . Some of the Hy-Vee stores also have a 91 and used to offer an 87 octane pure as well - that's what I use in the old Land Cruiser since it's fuel pump is pretty much NLA and super expensive . Being a '77 , it's not happy with ethanol at all and will drink it down to below 10mpg and produce less power overall - I hate the stuff .

 

Sarge

[WVHillbilly520H 10,369]

Supposedly the black "rubber" neoprene fuel line from Advance (and other auto parts retailers) I got this spring/summer is now ethanol compatible vs old black rubber hose, Jeff.

Edited December 20, 2016 by WVHillbilly520H

[doc724 924]

It is bad enough having fuel problems in the summer but in the middle of winter is downright unfair.  I hope your work area is heated. 

[608KEB 794]

5 hours ago, JERSEYHAWG / Glenn said:

With that black particle comment I am with Jeff on the fuel lines breaking down. On all my machines it's the first thing I replace front to back. Good luck, keep us posted.

 

Glenn

I hear you. I'm going to replace the fuel lines on the WH's that haven't been replaced yet. I didn't mean to turn this into a engines thread.

[Lagersolut 613]

I had a newer craftsman weed eater given to me earlier this year from the new owner of the house down the street . Said if you can get it running yours free . After fiddling with it, realized the fuel pick up and primer pick up were off laying in the tank . ....grabbed a small needle nose to reinstall the lines they crushed and dissolved like ice cream ....after careful thought I realized the ethanol gas these lines were soaking in as this guy was going through his divorce did it .....unit was only 2 maybe 3 years old ....barely used ....figured the diaphragms in the carb may have been ruined too putting the repair higher than a new one ....scrapped it .

 

That's the 3rd ethanol damaged engine I've encountered .

[608KEB 794]

I run Phillips 66 91 octane unleaded non ethanol in all my small engines.

Edited December 21, 2016 by 608KEB

[608KEB 794]

6 hours ago, doc724 said:

It is bad enough having fuel problems in the summer but in the middle of winter is downright unfair.  I hope your work area is heated. 

I insulated and put a gas furnace in the garage two years ago. Makes it a joy to work on stuff,

[lynnmor 6,762]

One weird problem I had with an Onan was the freezing shut of the vacuum pulse line on the back of the fuel pump.  If it is real cold, condensation inside the line can stop the pump from working.

[WVHillbilly520H 10,369]

Had that happen while snow blowing years back, think I put like plumbing insulation over the pump for the rest of the snow season to help cure that.

 

[Kurt-NEPA 755]

I had something like this happen on my 1988 520H.  I was mowing with and it bucked and stopped.  I got it going with the choke and limped it back to the shop.  Everything said a fuel problem to me.  To make a long story short, I cleaned the carb 3 times, replaced the fuel lines and filter and even installed an electric fuel pump.  Nothing seem to help.  It was running poorly and hunting under load.  In an act of desperation, I changed the governor adjustment and now every thing is fine.  I still think something got bent in linkage, but I can't find it.  I'm not suggesting this is your problem, but it is something else to try.

 

Good luck with this....

 

[entropy 104]

Everything seems to point to the fuel system but, the running for a bit then dying reminds me of a problem I had in my 520. When my motor got to operating temp the ignition module behind flywheel would fail (would bench test fine when cold, hence why I did not replace it after pulling everything to get to it and then pulling everything off motor again to replace it......derp). Would always start and run for a bit then die. Next time it dies check your ignition module and spark. 

[608KEB 794]

Update, I used the 520H on Christmas. I ran it for about a hour. I had no issues!