ONAN CLEANING EXPERT'S NEEDED

[BOB ELLISON 2,976]

Ok here we go again

I have a 1995 520h  that runs like a top and I want to clean the crap out of it. So to speak. I did check the right rear fins and they are clean, it's where everyone says to keep clean and some even cut vent holes for air. I did try to remove the blower housing where the  flywheel is and where the fuel pump is . How do I get the hose from the back of the fuel pump off ?? Does any one know of a manual or a post to show how to remove all the tins for cleaning . I will replace  all the gas lines and check all wires  under tins while I got it off. A picture is worth a thousand words.

[WVHillbilly520H 10,369]

The engine tins are a bit of a pain but doable, the oil filter has to come out/off though ,some use a small steam cleaner to help with removal of the accumulated crud after the tins are off or out of the way, now the fuel pump take the screws out pull the pump outward with vacuum hose still attached should be a squeeze clamp like fuel lines remove that and you may have to pry hose off nipple then a bolt in the end of it till you get the tins loose when putting tins back you'll need some long needle nose pliers to help get it back out to the fuel pump, some of the tins are bolted with the muffler heat shields below the air cleaner, hopefully have helped not confused you, also while your at it take the fender pan off and clean that hydro pump and fins really good too I used a pressure washer for that, take a look at "Good Friday" 520 clean up thread, Jeff.

[BOB ELLISON 2,976]

10 hours ago, WVHillbilly520H said:

The engine tins are a bit of a pain but doable, the oil filter has to come out/off though ,some use a small steam cleaner to help with removal of the accumulated crud after the tins are off or out of the way, now the fuel pump take the screws out pull the pump outward with vacuum hose still attached should be a squeeze clamp like fuel lines remove that and you may have to pry hose off nipple then a bolt in the end of it till you get the tins loose when putting tins back you'll need some long needle nose pliers to help get it back out to the fuel pump, some of the tins are bolted with the muffler heat shields below the air cleaner, hopefully have helped not confused you, also while your at it take the fender pan off and clean that hydro pump and fins really good too I used a pressure washer for that, take a look at "Good Friday" 520 clean up thread, Jeff.

Thank you wvhillbilly520h any help is good I did restore a c160. Frame off and the kohler is much easier for me. This onan is a lot different to work on. I'm hoping someone makes a post with pics to help us with our onans. 

[Gadget 37]

You might wanna make some notes about how the throttle linkages are BEFORE you take it all apart.  I had to remove the forward one (where the cable clamps) and the spring to the governor.

I didn't have to take the oil filter off. Once you get everything loose,  the cover kind of lift up slightly out, then down and to the rear. Reinstall in reverse order. On mine, some of the bolts holding the "tin" on were longer than the others, so you might want to make notes about which ones came out of which hole.

After going thru all the effort of doing what you are doing, I found everything very clean. BUT it was a GREAT learning experience. For me anyway, being new to these machines, nothing makes me learn faster than taking something apart and putting it back together. At least now I know, as will you, that everything is clean and air is flowing as it should. I learned (I think) that the air flows from left to right, very basic for the more experienced guys here but not for me. I know that there are many posts about venting the covers and they make sense, but I am starting to think that when you vent the covers, you are making an exhaust  port, I had thought they were intakes. Like I said, No way to learn other than breaking out the wrenches.

Good luck

[DougC 2,641]

Is it common for shroud bolts to break on these Onans during attempted removal? I need to do some cleaning and look for oil leaks on my rode hard and put up wet 88 520H and thought maybe it would be a good idea to ask.......

[WVHillbilly520H 10,369]

I haven't had any bolt breakage but just remember those bolts are mostly threaded into 28+ yr old aluminum if you have any stubborn bolts that break loose but get hard coming out reverse ratchet/wrench for a few turns and try again may have to do this a few times or even for the whole length of the bolt also after its backed out a bit some penetrating oil on the threads and doing the above helps too, that being said stripped threads property more likely than broken bolts just my experience and ,Jeff . Try to P.M. Boomers Influence, he's the Onan parts guy...

[BOB ELLISON 2,976]

10 hours ago, Gadget said:

You might wanna make some notes about how the throttle linkages are BEFORE you take it all apart.  I had to remove the forward one (where the cable clamps) and the spring to the governor.

I didn't have to take the oil filter off. Once you get everything loose,  the cover kind of lift up slightly out, then down and to the rear. Reinstall in reverse order. On mine, some of the bolts holding the "tin" on were longer than the others, so you might want to make notes about which ones came out of which hole.

After going thru all the effort of doing what you are doing, I found everything very clean. BUT it was a GREAT learning experience. For me anyway, being new to these machines, nothing makes me learn faster than taking something apart and putting it back together. At least now I know, as will you, that everything is clean and air is flowing as it should. I learned (I think) that the air flows from left to right, very basic for the more experienced guys here but not for me. I know that there are many posts about venting the covers and they make sense, but I am starting to think that when you vent the covers, you are making an exhaust  port, I had thought they were intakes. Like I said, No way to learn other than breaking out the wrenches.

Good luck

Thanks Gadget that looks pretty clean from what I have seen from others, I know mine is just as clean because the guy I got it from took really good

care of it. it was kept in a garage as I do all my tractors. But I want to know if its clean for peace of mind. I will clean it and  fix what hurts on it. 

thanks for the picture.

[coldbear 29]

Yep, Onan engines are a stretch to work on. Unlike a Kohler, they are a whale of an engine. Hillbilly is correct on Boomer the parts guy. He saved me a ton on my 89 520H and really helped with information. They don't come any better than the " Boomer of Minnesota" !