Who's Great Idea Was This?

[MalMac 1,328]

Well I got tired of just taking the top of the carb off my 520 today to clean it. Been having trouble with surging, gov. hunting real bad. The jets kept getting super small particles in them. I changed the filter new gas lines etc. So I decided to completely clean the carb. Who's great Idea was it, to have to take off the intake manifold to get to the carb bolts! To me its totaly insane the way its designed. Is it just me or have any other of you had these thoughts? I'll take a Kohler K anyday.

Tim

[Sparky-(Admin) 19,553]

I havent had to take mine off my 416 but I have heard its a crappy job.

Good luck with it.

Mike..........

[markslawnmowerworld 4]

I agree about taking a kohler k-series over the onan oppossed twins, but think of this if you ever get a chance to tear down an onan, you will be amazed at the enternal engineering....and design....a very well designed enternal engine.

just my opinion, and there hard to beat. :omg:

[markslawnmowerworld 4]

internal...... :omg:

[sorekiwi 761]

I have to agree somewhat with Mark here...

I have only limited experiance with the Onan, I bought a 520 with a half dead engine last year, and havent finished putting it back together again.

But as I pulled the one from the tractor down, and another that I got to donate parts, I kept admiring how well it was built. There are a lot of really nice "packaging" features on this engine, the pieces are nicely made and the whole thing gives you a feeling of a quality piece.

The Onans are renowned for their long service life and reliability in applications other than in the Wheel Horses, so I have to suspect that most of the problems we have with them are a result of the installation in he tractor. I really do think that the hoodstand/beltguard arrangement tends to make the rear cylinder run a little hot. The JD guys dont seem to have as many issues with theirs as we do.

If I ever get around to putting mine back together, I'll be able to give a better opinion on "living with an Onan".

[oldandred 15]

I heard some were that auto stores do sell in line filters

[Roger from southern Iowa 1]

Yes, you do have to take the intake off to remove the carb.

In my opinion, it is a small price to pay to have the quality and service the Onan engine had built into it.

I've worked on a lot of small engines and have found the most simple prevention of contamination in the carb is use a paper element fuel filter inline between tank and carb. I try to change my fuel filters twice a year and have very little problem.

This is just my experience, for what it's worth.

[Rollerman 290]

I will admit...Onans are a very smooth powerfull engine when they are running right.

But I'll take a Kohler K or Magnum myself anyday!

The carb is a job to pull, most of the time you can get the carb cleaned with just top off.

The last 520H I had was plagued with a dirty fuel system & had the flush the tank, replace the fuel line, clean the vacume pump & I still had to do carb surgery half a dozen times before I was satisfied.....& then I just sold it because the thing "spooked" me.

The PO had left the fuel cap off & must of had a lot of pine trees.

The older Onans with the siamesed carb/fuel pump were a pain too.

Just wait till you have to pull the starter....... :omg:

[rickv1957 70]

Yes the Onans are great engines but they are a little tougher to work on for sure,Rick

[MalMac 1,328]

I agree with all the post. The Onan is a well built engine and when its running good it has got the power. To me it just seems a bit fussy and a nightmare to work on or trouble shoot. Maybe I should add that I have always had Kohlers up until I came across 2 520s that needed a good home. I am more comfortable with the Kohlers maybe in time I will be with the Onans

Tim

[Herbl 10]

I own 2 520H's and had Carb work on both of them. I have removed the carb on both of them without removing the intake. Yes, it takes a little extra time to do this but with half turns of an open end wrench I was able to remove the carb, of course you do have to remove all the muffler shields (not muffler) to be able to do this..

[04fxdwgi 0]

Well I got tired of just taking the top of the carb off my 520 today to clean it. Been having trouble with surging, gov. hunting real bad. The jets kept getting super small particles in them. I changed the filter new gas lines etc. So I decided to completely clean the carb. Who's great Idea was it, to have to take off the intake manifold to get to the carb bolts! To me its totaly insane the way its designed. Is it just me or have any other of you had these thoughts? I'll take a Kohler K anyday.

Tim

When I had my manifold off, I installed a heli-coil in the manifold and added a stud with lock-tite, then just used a nut to hold the carb on. Very easy to do, if manifold is already off. I guess Onan didn't do it this way because of the 2 piece manifold

[Docwheelhorse 2,560]

I owned a low hour 520-8 speed and even though it was a --rare-- model I dumped it because I couldn't stand that carb setup and having to take the top off and clean the jets. I had the best filters I could get in the system and the jets would still get a miniscule item in them and it wouldn't idle. Give me a Kohler K or Magnum thank you very much!!!

Tony

[dr74go 1]

I also have a 520 that I removed the carb from. I did it without removing the intake. I took a cheap chinese wrench and bent it to fit where I needed it. It was a little time consuming, but it wasn't too bad. It was much easier than removing everything to get to the intake.