How mowing can destroy your ONAN

[B-100 Dan 7]

My 10 HP Kohler will plug the spinning screen in a simular way as this.  It gets plugged with that white fuzzy stuff of dandilions.  I keep a pretty close eye on it as I mow, when it looks like it's getting plugged, I head for the garage to plow it out as well as the whole motor, so it cools better.  Heat is not good for any air cooled motor, and what ever you can do to help it cool just adds life to it.  My two cents worth....

[ronhatch 406]

Hey B-100 Dan. My answer to those "white fussy" things;  Weed-B-Gon . 

[RMCIII 838]

Same issue would happen with my JD 212 Kohler, until I found the left side engine panel. Why not look at how that panel is constructed and see if one could be fabricated for the Onan?

[Wheelhorse84 87]

Take the screen off?

[B-100 Dan 7]

Hey ronhatch,  Thanks and I agree, problem is I don't think they sell "Weed-be-Gone" in a 55 gal. drum.  HA-HA.

[Brownta 5]

The problem is the Onan sucking so much air in. Tons more the the K-series. The Onan's fan has two jobs. One to air cool the engine, and the other to act somewhat like a supercharger. That rubber tube that runs from the fan to the air intake compresses and forces air in. That's why the Onan's filter cover has a gasket and a tight fit. Also the reason many seem to think the Onan engine is much stronger than the saki and k's in the xi/Lxi's. It really is a glorious design to maximize power in a small package. I also have this problem quite bad. I had one thought of making a chain guard, similar to what's on larger brush mowers. This would still allow the deck to suck in the air to lift the grass to produce a nice level cut, but should keep the larger clippings from being thrown out the front. I'm not thinking heavy chain. Maybe not even as heavy as what tire chains are made of. Just some light weight chain, painted up Wheel Horse red. Weld the chain links to a bar and utilize the holes that are already in the front of the deck and bolt that bar on. Fully removable, and inexpensive. I haven't tried this yet, but I'm planning on fabricating something up as soon as I get moved into my new place. I figure they would have to be bolted on the outside to prevent the blades from sucking them up and striking them. One thing I have learned is that mulcher blades exaggerate this problem. The use of the stock toro blades helps to limit this in normal cutting conditions. I had high lift mulchers on my 60" and just couldn't use them. They blew way too many clippings out the front. And the clippings were lots smaller, making the Onan pick up just about everyone of them. Purchased stock blades, and the issue (while still there) wasn't nearly as bad. I think the problem is the triangular design of the deck. Some of the other toro decks are made at an angle. There the side discharge shoot sits toward the front of the deck and the deck is angled in a way that allows air to flow unobstructed. Even the JD decks that are triangle shaped blow clippings out the front. But the Deere's air intake isn't right there to suck the up either. So it's not a problem. 

 

Figuring out a way to block the clippings while allowing air to pass into the deck is the most likely way to end the issue. (And maybe make some $ on the side to. Everyone with an Onan in there horse would want one. Especially one that is simply bolt on with normal hand tools)

 

Happy Memorial Day from Iowa!!

 

Tim

[Lane Ranger 10,943]

I hate to say it but maybe the Onas need a side cover like the JD's have on their 318!

 

 

[RMCIII 838]

Similar to the 200 line,

[Wheelhorsedairyfarmer 13]

Rear discharge side discharge, I usually end up with dandelion fuzzies on my k321, deck makes no difference, but I've never had it that bad! 

[JackC 617]

"Figuring out a way to block the clippings while allowing air to pass into the deck is the most likely way to end the issue. (And maybe make some $ on the side to. Everyone with an Onan in there horse would want one. Especially one that is simply bolt on with normal hand tools)"

 

Tim, I agree.  Keeping the clippings from blowing out of the front and left side (ONAN air intake side) of the SD deck should make a big difference.  A bolt on solution for the deck would be ideal.  Some kind of very light chain or rubber guard could do it.

[Brownta 5]

Does anyone know if the vacuum bagging system helps with this issue? I have also pondered purchasing one if it would help. I can get a new one for $800 from my local dealer. Which is a lot cheaper than a $2500 re-power of the 520. I was mowing yesterday and could only go about 10 minutes before having to stop and clean the intake off. I was only cutting off about two inches of grass to.(with my schedule sometimes it's more like 6") My place is close to a cemetery, so I figured with the holiday coming up, I better make it look nice. Stopping all the time makes for a long day of mowing when there is 2.5ish acres to mow. Anyway, before I start to ramble again, if anyone has used the vacuum bagging system, let me know what you thought about it and did it help with the clippings coming out the front of the deck?

[Brian K WheelHorse 28]

My Onan packs grass the same way. I mounted my high temperature "Sounder" alarm to the high-temp engine sensor, but I have to finish wiring it up and testing it. I was thinking about mounting a brush that could "push off" the clippings real quick. The problem is that the Onan does need that massive volume of air. Building a screened louver/side cover may make it worse by restricting air flow.

[Wheelhorse84 87]

Vacuum bagging doesn't help. I have one and it still collects there like crazy.

[varosd 1,185]

Here's my solution!  note brush screen sans grass clippings. plus no PTO engaged so the Onan is all you hear!

 

 

 

[MalMac 1,331]

I Have a Vac system and I think it makes it worst. Like I mention earlier there was a Leaf Baffle that was offered for the 42"SD deck. It bolted on the front and went under the deck about 2 inches all the way across. It was supposed to help with the blow out from under deck and cause more vacuum. It was quite pricey. Probably could figure out a way to make your own. It was only offered for the 42.

[papaglide 542]

Sounds like the leaf baffle would help for sure. Very interesting to learn about the supercharged Onan. Never knew that!

[Brownta 5]

It's not a true "supercharger" like on a car. But it does help with forcing air into the engine. Does anyone have a CFM meter that they could use to compare the K-series to the onan to see how much air there sucking in?

[StWeiler 6]

Hey Brownta....what's the name of the dealer down that way?  I think I need to give them a call. 

[SAM58 30]

I use a 48" SD Deck with my 520H, and do not have as bad a problem as some of you.

dry grass is worse to float around and get sucked into the engine.

Out of habit I blow out the grass each time I mow...

[JackC 617]

I came up with a solution and now I all I need to do is paint it red and sell copies.  I was mowing with my 520HC and 48 inch SD deck.  When I was mowing with my 416-8 at the start of this thread I notice the clippings flying out from the front of the deck and getting sucked up into the flywheel screen.  Same thing was happening with my 520HC.  I had to clean the screen about every 5 minutes.  So I took a piece of cardboard and some bungee cords and came up with a simple baffle to block the clippings from getting sucked up into the flywheel screen.  It worked great.  After a half hour of mowing there was hardly anything stuck to the screen.  Now all I have to do is paint it red put a wheel horse sticker on and get rich selling copies.   Maybe I will apply for a patent also.  Maybe someone can come up with something better?  Here is my solution.

 

 

 

 

[papaglide 542]

Ingenious! I have to figure something out for my 416-8. That clutch pedal needs to move.

[Brian K WheelHorse 28]

I came up with a solution and now I all I need to do is paint it red and sell copies.  I was mowing with my 520HC and 48 inch SD deck.  When I was mowing with my 416-8 at the start of this thread I notice the clippings flying out from the front of the deck and getting sucked up into the flywheel screen.  Same thing was happening with my 520HC.  I had to clean the screen about every 5 minutes.  So I took a piece of cardboard and some bungee cords and came up with a simple baffle to block the clippings from getting sucked up into the flywheel screen.  It worked great.  After a half hour of mowing there was hardly anything stuck to the screen.  Now all I have to do is paint it red put a wheel horse sticker on and get rich selling copies.   Maybe I will apply for a patent also.  Maybe someone can come up with something better?  Here is my solution.

 

 

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Thanks for the R & D work Jack....

[JackC 617]

One other thing I noticed when the flywheel screen was getting plugged was that the engine was surging and revving past 4,000 rpm.   When the flywheel screen gets plugged the air fuel mixture must get way to rich and when the engine is under load the governor and the carburetor must get confused.  

 

Plugged air flow to inhibit proper cooling combined with the engine surging above 3,500 rpm could certainly lead to an overheated engine and then failure.

 

Now we know the clippings blown out from the front of the SD decks get sucked into the flywheel screen due to the massive air intake required by the performer series ONANs.  How many ONANs have been lost due to this problem?

 

We no longer need to be baffled by the plugged flywheel screen problem when mowing.  In fact, the solution can be a baffle of some sort maybe even on the deck itself.

 

Put your thinking caps on folks we cannot afford to lose anymore ONANs especially the ones on our horses.

 

How about a "Best Baffle Contest"?

[leeave96 487]

I'm wondering if you took a piece of round baler belting and fastened it to the front lip of the deck to bring the deck lip down even with the side of the deck - would this do the trick?  I don't have it to look at - but I think the 42 inch RD deck doesn't rise up in the front like the SD decks do and the RD decks (42 or 36 inch) don't cause this problem with my Wheelhorse tractors.  With the rubber belting, if you hit a rock or bottomed the deck on some lumpy ground, it would deflect and not cause damage to the deck.

 

Bill

[JackC 617]

Bill, I think you are correct about the front lip of the RD deck being closer to the ground than the front lip of the SD decks.

I have both and will compare.  Something flexible on the inside front lip of the SD deck should work. There are metal baffles on the inside of the SD decks to protect from the blades hitting it.  The non recycling RD deck is totally different underneath and has no metal baffles like the SD decks do.