520h with spark and gas wont start

[jimbo7921 8]

Just need to know where to look from there. Started and ran fine yesterday now it wont fire up i am getting fuel and i have spark just not sure what to look at after that. Any ideas wood be appreciated thx jim

[Hodge71 663]

Compression check…very possible it dumped a valve seat…typical for an Onan….

[dbartlett1958 96]

Like Jeff said, if you are sure you have fuel and spark, compression is all that is left to make one go. Recheck your spark and fuel at the carb. Try putting a little gas directly in the plug hole, or use some carb cleaner in the intake and see if it fires on that. That will give you some more information to work with.

[jimbo7921 8]

Ok waiting on a buddy to help me with a compression test. Thought i wood check over a few things while it was down like air filter, threw in new plugs and decided to check the oil pulled the dipstick and got a big wiff of gas in the oil. Is that just flooding the crap out of it or carb issues? Thx jim

[woodchuckfarmer 333]

could be from the fuel pump too. a bad diaphragm can do it

[JackC 616]

Ok waiting on a buddy to help me with a compression test. Thought i wood check over a few things while it was down like air filter, threw in new plugs and decided to check the oil pulled the dipstick and got a big wiff of gas in the oil. Is that just flooding the crap out of it or carb issues? Thx jim

I have done that.  The oil level indicated way over fill from un-burned gasoline mixing with the oil.  On the 88 and 89 520H there is a lever to allow you to pull up on the drive belt idler pulley and disconnect the transmission from the engine to spin the engine faster.  

 

If you have been using fuel with ethanol it does not take long for the ethanol to absorb water and to cause the carburetor to not meter fuel to the engine properly.