Archive through December 22, 2011

[thenrie]

dlcook: I'd start with the cheapest/easiest fix first. Get a can of PB Tune-up-in-a-Can. Spray it into the carb, according to the instructions, and see if that doesn't fix the problem. That stuff is great! If that doesn't work, I'd look at your timing. Next I'd remove the carb and give it a thorough cleaning. Next I'd try replacing the needle valve, float valve, etc. and maybe rebushing the throttle shaft. Your problem could be a vacuum leak through your throttle shaft. To test for that, spray carb cleaner, like Gunk Carb Cleaner, on the throttle shaft ends on the outside of the carb (NOT into the carb throat) while it is running at about 1000rpm (high idle). If it stumbles or the rpm drops you have a vacuum leak.

Whatever your problem is, I think you should be looking at the carburetion as your first stop. Governor problems don't normally make the engine run rough, unless they let the engine overspeed, then it may start running rough due to valves floating or sticking, but that doesn't happen when the rpm drops under load. If the engine runs smoothly, but starts running rough under load, you're probably looking at carburetion or timing.

Luck.

 

[dfrisk]

TONY - Like the old timers say, "if all the signs point to carburation problems with an engine it's probably ignition" was correct in my case on my 982 this past summer.

My 982 ran great the first couple mowings and then one day I started it, idled it to the shop and greased & gassed it up, throttled it up a bit to engage the mower deck and it started running REALLY rough. I replaced the spark plugs, reset the timing, removed & rebuilt the carb, installed a new fuel pump I bought 6 yrs ago over the next 3-4 weeks and it still ran like crap. I got a brand new set of points & a condensor and installed them, the whole time thinking it will start & run like crap afterwards and to my utter amazment it started and has run great ever since. The points didn't look too bad so I think it was the condensor.

The biggest problem with these old Onan's seem to be the two-piece intake manifolds coming apart and leaking raw air into the intake and causing the engines to run lean and surge. The manifold is a diecasting with the top side made from thin sheet metal bonded onto the diecasting. Another TERRIBLE design!

MIKE - This other forum doesn't archive old posts like Charlie does here so there may not be a way to retrieve this old topic but I'll look. I'm pretty sure there's only ONE Onan with this fix out there. I've never been happy with the way the governor in my Onan has worked over the 11 yrs & 350-360 hours I've run it. When I'd mow from short grass into taller grass and the load would increase slowly the RPM's would drop gradually, but when I'd hit the throttle it would rev right up and pull hard but would over-speed when the load decreased. The plastic ring sticks to the cam gear when cold but plastic expands when heated about FIVE times as much as cast iron so as the engine gets warm the problem gets worse.

A year ago I had a small area in my back yard I didn't mow for over two months, 2000-3000 square feet probably, the grass was well over a foot tall and very thick. I have a 50C deck on my 982 and late one afternoon I mowed it. I creeped along at a higher than normal RPM setting and mowed the whole area and was impressed with the way the engine was pulling the load, never a shortage of power. I was trimming around a tree and looked forward over the hood and there was a cloud of blue smoke flying forward from the frt of the tractor. No funny noises to warn me of any problems so I slowed the engine speed a bit and stopped the tractor in a place I'd already mowed. After 20-30 seconds the smoke stopped. Without even breaking a sweat the engine was burning the mule drive belt!

I know all the manuals say when you replace a gear you should replace both the drive and driven gear but the cam gear is easy to replace, if I was fixing my Onan I'd just replace the cam gear. There's so little load on those gears there shouldn't be any bad wear patterns. And pulling the crankshaft & replacing the gear requires complete engine disassembly. And I really hate to pull the engine completely apart with only 350-360 hours on a complete rebuild.

 

[thenrie]

Dennis: If I read Weaver's post correctly, his problem is different than what you had. Yours started running rough with an increase in rpm, not an increase in load. If an engine is just running rough, like yours was, the first thing to check is simply engine tune. The cheapest and simplest thing first. Clean the carb (with carb cleaner), check the wiring, check the points and spark plugs, fuel filter, plug wires, engine ignition wiring, all that before you even buy any parts. You'll find 90% of engine problems by this time. Then buy the parts you need. Probably just easier to replace points, condenser, plugs, air filter, fuel filter, etc and give the engine a full tune-up, rather than spend time searching for the problem if it hasn't been tuned up in a while.

Your tractor's problem would have been found by this time, so you would not have needed to go any further. If that doesn't work, then start with timing. Check the timing, reset as necessary,but then you should have done that already, if you did a tune-up. Now look harder at the carb - remove it and clean/overhaul it. If that doesn't fix it, and since you already checked your electrical, next is mechanical.

Weaver's problem, as I read it, is that it runs fine until put under load, then starts running poorly. Not a matter of the engine changing rpm under load and surging when the load is removed. Just runs rough under load. Doesn't sound like governor to me. Sounds like he needs a tune-up or carburetor work.

The other problem you list re the Onan engines and the intake cracking, is a vacuum leak problem. That can easily be diagnosed with the carb cleaner test I described. Just spray it on the carb and intake manifold while the engine is running about 1000rpm. If the rpm drops or the engine stumbles, you have a vacuum leak and it is sucking carb cleaner into the engine through the leak.

Not meaning to be argumentative, but I think his problem is carb-related.

 

[dfrisk]

TONY - My Onan would skip at idle after it started running rough, and it would never run right at any load or RPM, even to the point of dying while mowing a time or two. Then sometimes it almost seemed to run O-K, except for the governor issue. I was convinced I would find all kinds of crap in the carb float bowl but was surprised it was almost sqeeky clean inside, but I installed the rebuild kit anyhow. I had a small gas leak due to a bad fiber washer on the main fuel adjustment screw so it got a complete rebuild. I did install a new inline gas filter too before the rebuild. I was convinced I had crud floating around in the carb the way it was running because it acted like it was running lean and would stumble and almost die and then recover occasionally.

Even after the engine died the time or two it would start right back up quickly, so was 99+% sure it wasn't a wiring issue. The intake manifold was replaced when the engine was completely bebuilt just before I bought the tractor in 2000 so was 99+% sure there was no intake air leak except for maybe the manifold to barrel gaskets and I did eventually order them with the points & condensor but haven't installed them yet.

The engine was rebuilt, tractor repainted, four new tires, new dash panel & gauges including new hour meter installed just before I got the tractor, think the hour meter showed 16 hours when I got it. It started running bad with about 340 hours on it. I had never done anything except check & adjust the ignition points 2-3 times in all those years & hours. So technically it was over-due for a tune-up by about 90-100 hours, so I bought the parts and installed them. Not sure if you've ever timed an Onan B48G in a 982 but there are NO timing marks anywhere to time the engine, you just set the point gap. Another BAD design feature. As simple as a Kohler K-series engine is they have timing marks!

I've been around tractors, trucks, engines in general that have had 500-600 hours and more on tune-ups and know how they run. They may be a little tempermental on cold starts and while warming up but generally still run O-K. The plugs & points in my #1 snow moving Farmall Super H I installed in about 1971 or 1972, tractor has about 300-400 hours on them mostly idling and cold weather running and it still runs smooth. I started it the other day to install the snow blade & chains and do some loader work around the house, first time it's been started since MAY this summer and once it finally got gas into the carb it started right up.

Far as trouble-shooting someone else's engine problems over the internet, I normally stay far far away from such discussions. You seldom get enough info to really understand what exactly the engine is doing. Not sure who Weaver is your talking about, thought it was Don Lee Cook who had the poor running 982, but you may be correct that he has carb problems, but his second post says he thinks his Hydro is slipping. That's a totally different subject!

What's odd, this summer I mowed with my 982 maybe 6-7 times and switched to my K321-powered CC #72 to mow one day. I hadn't mowed with it since summer of '10. I got about 2/3rds done with my two acres and IT Started running like crap too, same symptoms as the Onan in the 982. New plug, points & condensor cured it too. I personally don't think the new conventional points/condensor ignition system parts are made, mostly off-shore, to provide the same long life as they did back years ago into the 1970's when electronic ignition became common on auto engines. But the new Carter carb rebuild kit is sitting and waiting for the next time it "hiccups". It got a complete Killer Kohler rebuild back in '05 and had run about 150 hours total when I had the problem with it this summer.

 

[sblunier]

Tony H.,

Nice multiple hitch. I would consider adding some straps from the ball to the upper corners of the tractor frame to carry and stabilize the tongue load on the trailer. Even with the reinforcement of the drawbar plate, there is a very high load on those three 3/8" bolts in the CI case holding on the drawbar.........I'd hate to see you crack the case with a heavier than normal load on that ball.

 

[dross]

Tony, The easyiest and cheapest thing to do with one of these engines first is put a cheap spark tester on it. I think I paid 2 bucks for mine and then learn how to use it. Being able to look at the condition of the spark itself will tell you a lot about the condition of your ignition system.
Dennis, I chased ghosts on an H one weekend when I did a carb rebuild and ignition tune-up at the same time. Believed in my heart there was something in the carb, turned out to be a bad new condenser.

 

[dlcook]

I appreciate all the discussion but my problem is the hydrostatic transmission. My motor has been rebuilt to very exacting specs (not by me, in other words!) and is running fine; no internal issues or carb issues. Even when the tractor slows down under load, the motor is fine. Any thoughts concerning troubleshooting the hydro? I've a couple spare hydros from some 682's i parted out and was thinking of swapping one of them or parts from them as needed, if thats possible.

 

[hsimon]

Wishing everyone a very Merry Christmas.

 

[dtanner]

I got some Mail today,most of it arrived . Seems I`am missing some bolts to install this.Could someone post what I need to install this . Merry Christmas everyone.

 

[digger]

Time to hammer on Little Donnie Tanner again!!!!

So it's to much trouble for ya to go to the manuals section and download the installation manual and see what your missin?

CLICK HERE goof!

 

[dtanner]

Charlie "Digger" Proctor

Thanks for that info ! This confuser is so old (582) lol that it takes forever in the manual section to find what I need. But I do think you could use some Xmas Cheer . Thanks again, Little Donnie Tanner .

 

[digger]

I loose that when I see boxes shipped like that!
How much freakin trouble would it be to wrap the ends of sharp ends with heavy paper or cut a piece of cardboard to line the inside of of a box that shouldn't have been used in the first place!
You can't believe the way some people ship stuff these days. It's like they left their dang brains in bed when they got up that morning.

It's not ROCKET SCIENCE folks!

There, I'm done with my No.1 pet peeve for the day.

 

[dfrisk]

DAVE R. - Dad wasn't happy with the way the Super H was running back in '68 when he first got it. We had the carb off a couple times that first summer. But I did a tune-up, new plugs, points & condensor every fall, about 250 hrs like the books always said. One winter Dad's M got to running really poor, He'd put A-C spark plugs in it before corn picking that fall, along with IH points & condensor. He found an old set of Champion D16 plugs I'd taken out of the Super H, cleaned them up & installed them in the M. It didn't run "perfect", it always had a "hiccup" when you pulled the throttle back hard under no-load since the M&W sleeves/pistons were installed in about 1965. I don't think the small parts package with the different advance springs for the distributor or the carb jets were installed. It pulled like a raped APE and started & idled good, just has that hiccup. But Dad ran those old Champions for another year or two. I'm probably the LAST GUY on this forum that still uses Champion plugs in everything.

I used to use AC Delco "Uni-points" in my first car, '70 Nova with 307 SBC, points & condensor all in one piece. Dad had a tach & dwell meter, distributor wrenches, even the flexible shaft GM distributor points adjusting hex wrench screwdriver, made a GM tune-up so much quicker. I guess if cars/trucks still had points & condensor ignition I'd still be a GM fan.

But it's really sad that engine component companies are so greedy now that they have to export work like condensors, ignition points, etc out to low cost countries so when you pay the high prices for new OEM parts it's like rolling dice whether your tuned-up engine will start & run. The points/condensor for my Onan cost almost $40 total, $20 for both the points & condensor. Then there was shipping on top of that! Years ago I used to buy plugs, points, & condensor for a Farmall H/M for bit more than a Ten Dollar Bill!

 

[kphill]

Dennis..I am no fan of Champion spark plugs..Before I install a set of plugs, I always check them with an ohm meter from the connection on top to where the threads are.. You would be surprised how many new plugs you find with a reading, which means your spark is mostly going to ground instead of jumping the gap..Champions seem to be the worst..In an 8 pack of plugs I would usually find about three that had a reading. Never had real good luck with them..

 

[snicklas]

Don,

If you want to package that back up, and send it my way, I believe I have all the bolts necessary to make it work.......

Then I would have a use for those two little ports on the front of my 1450.....

 

[dtanner]

Kevin Hill

Spark plugs wire sets, I took my meter to the parts store with me a few years ago,A set of 8 wires had 3 that did not pass for new. Man was he ever pissed I wanted to pick another set for the bad ones. But all he did was stuff the ones I would not take in the box for the next guy to buy.Just think the next guy got a set of wires that 6 were less than 50% omage.My .02

 

[kphill]

Don, Most people think just because it is new in the box it is good stuff..I learned the hard way years ago when I tuned up a running car and when I was done it would not start...That is how I found the bad brand new spark plugs..

 

[dfrisk]

KEVIN H. - The only thing I've ever tested with my ohm meter was the old glow plugs out of my PSD. I had four otally dead GP,s two bad ones and two that were O-K still @ 240,000 miles. But it still started one day @ 15 degrees F with heavy 15W-40 oil in it after sitting in the parking lot at work for almost 12 hours. Started much better with new GP's though! That cold day with the old plugs it started on 3-4 cylinders and picked up 2-3 more in the first 10-15 seconds and finallyy picked up the last cylinder after about 30-40 seconds. That HEUI injection system was making some terrible noises pumping that thick oil up to 2000 PSI!

I've got some newer used Champions and some old unused Champions I'll have to test. The only engine I have spark plug issues with is the tired old K161/181, not sure which it really is in the CC 70. It's about 10 years past needing a rebuild and I only use it for light duty work, pushing a little snow around, spraying, towing the cart. I normally try to run J8-C's in it but have run NGK's a time or two.

It's sad that 25-30 yrs ago Champion was THE PLUG to run in ALL motorsports. Most OEM's designed their engines around specific heat ranges of Champion plugs, companies like IH, JD, Kohler, Onan, etc.

 

[dtanner]

Scott Nicklas

I know its Christmas , but not a chance of me shipping that out lol.

Dennis Frisk

lol you do know that a Cummins don`t have glow plugs !

I had a few old two stroke bikes years ago and found that NGK were the best for lasting and some dependability .

I have to make a trip to town to get me some bolts and then mount that cylinder on a 54" blade I have here. I will have to install the blade on my 1512 Diesel because that has front ports. I might have to send Aaron and order for a kit so I can use the 149 with front ports. The 149 is a great tractor and I like the sound of the stack also lol.

 

[ghaynes]

Dennis and Mike,
I saved the photo's from the other site because it seemed to me a viable fix for the Onan governor issue and I run several Onan powered machines, thinking I might need to apply the "fix" in the future. I do not remember who originally posted it but I remember they followed up with a post touting success of the idea after a season of running the engine with the "fix" part applied. Also I remeber it being stated not all Onans have the appropriate slot in the cam gear to be able to apply this type of "fix", and Dennis you were right in stating the engine would have to be removed and dismantled removing the flywheel to do this repair. In the photos the first two show the physical size of the part and the second two show the cam gear slot, one with the part in place and one without. The small groove laterally across the part is to clear the cam gear "bell" cup that contins the flyballs. The piece was made from standard nylon and it was stated not too dificult to make. Hope this helps........Gary H.