New Problem HELP! Possibly big onan troubles?

[Jeff]

When I got my saw from doug I noticed that the oil was over full. One of the first things I did was drain it and change it. Fast forward. I have had a series of issues with the way the engine has run. I have cleaned the carb, I have replaced the coil, coil ignigion wire, sparkplugs and the circuit board. I just got into some real sawing the last week or so. Red pine around 12 to 16 inches, 12 feet long. I have had some real issues with power. engine idles good, runs smooth when powered up, but loses power as soon as you start to cut.

Back to the changing of the oil. A couple days ago I noticed what I though was a fine mist coming out of the exausts again. I had seen it before, then I saw what looked like specks of oil on things.  I shut the engine down and checked the oil. Now, I could not remember if I actually checked the oil when I changed it after first getting it. I looked up the amount of oil in the manual, and added exactly that to the engine. The oil wasa once again, over 2 inches over the full mark on the dipstick.  I thought well heck, I must have made the same mistake doug made. So, I drained the oil and changed it again. THis time, I didnt look at the manual, I just added oil until it was exactly full according to the dipstick. Exactly 2 quarts it took. (Engine is the P24)

Well, I sawed two more logs after that. I have benn using what I though was way to much fuel, but being new to this, didnt really know. Probably 5 gallons to saw 550 feet of lumber. I just went out and checked the oil again, and its over 3/4s of an inch OVER the full line again.  Its gotta be gas going in the oil.

Please tell me there could be a simple answer to this. I have been leaving the gas tank connected, never occured to me to disconnect it when leaving the mill set.


Another symptom. The mill starts hard. You have to crank it quite a bit, but then it takes off and smokes then clears right up. It acts like it is flooded almost.

[Paul_H]

Float needing adjustment?

Do you have some close up shots of the carb and intake?

[Fla._Deadheader]

 Some Onan's have a vacuum fuel pump, mounted on the cooling shroud. Could it be the diaphragm has a hole and the crankcase is being slowly filled that way

[Bibbyman]

I've seen fuel pumps fill crank cases on small block Chevy engines.  Was at a garage one time where they were putting in a new engine in a Suburban.  The mechanic was telling how the owner worked for days trying to get it started so they had it towed out to the garage to have a new engine put in it.  (that sounded drastic to me but…)  As he continued the story,  he went over to take the timing cover off the old engine.  Gas and oil came pouring out.  Yep,  the crank case was full of gas.   Probably nothing wrong with the engine a new fuel pump wouldn’t fix. 

I have no idea if that’s an answer to you’re problem but I’m happy to tell my story…

[Paul_H]

Fuel pump makes more sense don't it ? I doubt WM would have a gravity feed setup on their mill.

Hopefully the problem is solved for the price of a new diaphragm

[Jeff]

I thought that fuel pump was "Impulse" or something like that? It actually has some sort of line going through that shroud?  I do have parts here. I got a pretty good gift at the pig roast. Kevin_H brough up his onan that he has cracked the block on and gave it to me. So I have a complete parts engine here.  I just hope the heck it aint a major engine malfunction.

[Paul_H]

The good news is the impulse comes from the crank case so it is probably slowly feeding back to the case.I think you're in good shape having a spare pump handy,as long as the diaphragms in that pump are OK

[ladylake]

Jeff  Sounds more like the carb to me. a bad fuel pump wouldn't put gas in the intake making it start hard and wouldn'd cause a power loss untill the oil got way overfull.  I'd check the float level as mentioned. Also the float for leaking Maybe it doesn't  float anymore, and put in a new needle and seat. Make sure everything is tight in the carb.   Steve

[ARKANSAWYER]

   Most of the time the carb is the problem like what you are talking about.  You can take the line off and do a vaccume check on the back side to see if the pump leaks.  You can take the line off that runs to the block and suck on it and if you get a gas taste then your pump is leaking.  Most likly it is a bad float or needle seat valve in the carb.  I would check it as the gas in the oil is causing lots of wear.
  Most of the time when the pump is bad the engine will die while under load but a leaking seat valve will drip gas into the oil the whole time it is off and cause the hard starting after setting for any time so I think carb.

[hiya]

I had a rototiller that the float would stick. I had to turn the gas off or the oil level would be way high the next time I would go to start it. Had a spair carb, that took care of it.
Richard

[twoodward15]

Yep, sounds like you need to do a carb rebuild.  It's probably actually the needle that is stuck in it's orifice, causing the float to constantly be down and letting gas pour in.  You could probably get away with just getting a new needle and float.  Be gentle when you pull that pin out that the float rides on, those ears can break off.  Fortunately it'll work fine with only one to hold the float, you just don't want to break both of them.

[Ironwood]

Jeff, My Gator HPX was loading the crankcase as well. A simple carb adjustment and now it's fine

               REID

[Bro. Noble]

We had a similar problem with our Onan.  Finally put a new carb on it and everything was allright.  There was a diaphram in the old carb that was bad.  I had a thread on it a couple of years ago.

[Jeff]

I'm thinking what ever is wrong has been wrong due to the oil level being off when I got it. I think what I will do is switch out the carb. I have the one Kevin brought up. I'll take it apart while I have it off and give it a cleaning. I didnt see anything wrong with mine when I had it apart to clean it. I did have the needle out of it when I had the top off the carb,

[Rockn H]

Jeff, I have a 24 hp Onan myself and you couldn't have described a problem I had any better.  Unless you had mentioned the oil smelling of gas.  It was the needle and seat in the carb.  None of the lawn mower shops in a 60 mile radius that I checked could get parts for an onan.  I would have went to Cummins so my local shop used various parts to make a rebuild kit.  Cost me $5.00.  Anyway a new needle and seat fixed me up. 

[Lenny_M]

 Jeff sure does sound like the needle valve and or float.with the fuel system full and engine off disconect the fuel line and blow into it. air should not go in. start engine with fuel disconected and let it run till it stalls out.blow into fuel line and air should go in.
 5 Gal for 550ft is too much, I usally get about 1500ft

[Jeff]

Do you think its worth a try to first just take off the top of the carb and try to clean the needle and seat with carb cleaner? Or should I just change it out or change the carb since I have the one from Kevin.

[Rockn H]

If the needle and seat look good ,and it is still letting enough gas through to fill up the crank case you may want to check the float.  Take it out and shake it , so you can listen for any gas inside.  Letting a mill set will often cause condensation to form and water will often cause carb parts to rot.

[sparks]

Jeff, I checked with our engine man here and he says definitly the carb.   Thanks

[Bro. Noble]

If it has a rectangular plate on the front lower left,  there is a diaphram in there that will cause your symptoms if it has a hole in it. 

I was told that there wasn't such a thing and that I must have the wrong carb on ours.  A friend who is an Onan dealer for his own use (he has a contract to maintain gen sets for a communication tower outfit) said he would see what I was supposed to have ane get one for me.  It was just like the one I had----with a diaphram in it   That fixed my problem.  I had cleaned the carb,  changed needles and seats,  and adjusted the float numerous times.  It was the DanG diaphram that it didn't have

[Minnesota_boy]

Jeff,
If you are at all handy, taking the top off the carb and cleaning the needle and seat is about a 10 minute job.  Unless your time is worth a lot and all booked up, I'd try that first.  You can always spend money on it later if needed.

[D._Frederick]

What type of carburator this engine have, an up draft or down draft?

[Jeff]

Well I would guess its a down draft as it sits on an intake manifold and has the aircleaner on top.

[ladylake]

Jeff   Make sure to check that float and also make sure the little gasket is under the seat, could be someone left it out.  Steve

[Coon]

Well, well, well,  seems that everyone is jumping to conclusions way too fast.  There is one thing that nearly every mechanic or mechanically inclined person misses with this situation nearly every time.

CHECK THE MOUNTING FLANGES OF WHERE THE ENGINE AND CARBURATOR MEET.  OFTEN THERE IS AN INTAKE GASKET IN BETWEEN THE FLANGES AND THE SLIGHTEST BIT OF AIR THAT GETS THROUGH WILL CAUSE FUEL TO  CONTINUE TO BE SIPHONED INTO THE CRANKCASE. THIS IN TURN OVER A PERIOD OF TIME CAN CAUSE THE NEEDLE AND FLOAT TO STICK IN THE OPEN POSITIONING AS IF THE ENGINE WAS STILL RUNNING.

[ARKANSAWYER]

   Sorry Coon that only happens way up North where it gets so DanG cold a body can not breath.        Jeff just got a sticky seat or a leaky float.

[Jeff]

I'll probably crack her open tomorrow. I aint got no logs and Tammy has the last of her boards we cut pounded up on the latest project so I might as well git er done before we get some more logs.

[beenthere]

There's been a couple hints given out on this 'latest project' .............. one of these days we may find out what it is, other than something to keep Tammy busy............

[Jeff]

 

[Paul_H]

I wonder if Jeff is building a wood stove? 

[Jeff]

Notice the list...

[Chet]

I wonder if Jeff is building a wood stove?

If he is, I hope he's buildin' it out of noncombustible wood. 

[Jeff]

sounds like the makins of annuder chet joke.

[Tom]

It's got nuthin' to do with nuthin'.  Just an incident that happened years ago up in Folkston.

A barn was being built and one of the friends had volunteered to help.  There is a lot of volunteering up in Folkston.   This fellow was johnny on the spot, but, you had to work around his mental slowness sometime's.

"Possom!", came the call from the roof.  "Bring me another board".

"What kind of board?", came the reply from the other side of the building.

"A 1x6, we're sheeting".

"Do you want a wooden one?" 

[Jeff]

Got the carb off and this fell out of one of the ports. I dont know which!  can someone help or does someone have a manual?

[DonE911]

Jeff thats just an extra part.... you don't really need it 

Kinda like those extra things you ended up with when you take something apart and put it back together....  I was always in trouble when I asked my grandfather where this extra part to HIS lawnmower was supposed to go

[Jeff]

I'd kinda like to put this one back in as my extra parts can is way to full...

[DonE911]

Yeah I understand....  thats why we buy our coffee in a can instead of them vacume packed bags

[Bro. Noble]

Oh Jeff, 

You're just blogging us,  aren't you

[Timburr]

Good choice of a new- found word....blogging

[D._Frederick]

Jeff,

Look for an openning that has a seat for the round end to seal against.

[pigman]

In my opinion it goes in hole  G  in your picture. Ok, I don't know.   The reason I bought WM  with a diesel was to keep from having carb problems.

[Furby]

Just guessing from looking at the pic, but "B" looks like it might be it.

Look at the other half and see if there is something to indicate where it goes.



Just take the other carb apart and this time take note of where it falls out from.

[Jeff]

with a little help from wood-mizer and with the post from  D._Frederick  I narrowed it down to a pretty good guess.   None of Wood-mizer's books show the part that fell out.

Furby, you dont want to know what I did before I made this post.

I dont think the carb was the problem. When I had both of them off, I could turn them updide down, and try to blow into the fuel lines and the needles were doing thier job, No leak through that way, regardless, I cleaned both carbs again but put the old one back on. I then pulled the ful pump.  The hose going to the back was wet inside, althoug I could not get it to leak gas while blowing on it, I think this may have been the problem. I hope. I put the one on off of kevins engine, pumped up the bulb, and after changing the oil AGAIN, firesd it up. Started right up. Shut it down for a few minutes and it fired off quickly again, this was have way through the thunderstorm so I figured I would come in and get dry clothes on.   I did power it up a couple times and it seemed to be running smoother. I hope this is not just wishful thinking.  When it quits raining I'll go try to start it again. If it fires right off I think we have something, as anytime it has set in the past, it starts real hard.

[Furby]

 
Sorry for laughing, but I can make a pretty good guess what ya did! 

Can't say I haven't done something like that myself...................

[woodbeard]

I actually just had mine apart today beacause my engine seems to be running rich, too, so I was checking the needle valve in it.
I'm just going on recall, but I seem to remember the spring being in hole E.

[Jeff]

Yep, E is where I ended up putting it, there is a small brass bin on the top of the carb that fits into the top of the spring.  THe thing started so, so far, so good.

[Rockn H]

Jeff, you weren't trying to mess us up with F were you?  Looks like I see threads in that there hole.

Glad it sounds like you got it figured out.  I'll have to remember that one since I'm running an onan also.  I would have never thought about the vacum operated fuel pump sucking gas back through the intake.

[hawby]

Jeff,

Did you say, "Rain?" What is that?? We are so dry down here. The weatherman keeps promising it, but the ground is cracking.....

[Furby]

I hear ya Hawby!
Was wondering what that was Jeff was talking about.

[Jeff]

I bet we got close to an inch, but thats the first rain we had had since two days before the pig roast I think.

[Furby]

I think I've had less then 3" since the end of April or early May.
That was mostly in 2 or 3 storms.
East of here was getting dumped on a lot the begining of summer, I didn't get hardly anything.
Couple weeks ago my parents had a heavy storm that took down parts of trees in the neighborhood..........5 miles North, I had sunny skies.
It's odd when they are showing on radar that you will get hit in a couple hours and you think of all the stuff that you have been leaving outside without worry of it getting wet. You then go out and pick things up and ..................... no rain!
Rain is now out of the forcast for another week.

[ladylake]

Jeff  Did you give it a good workout yet? Running good?  The pulse hose to the fuel pump will always be wet, same as the oil cap or inside of the crankcase as that's where the air is coming from to run your fuel pump. Most likely there was a speck of dirt in the carb that you got out.   Steve

[Jeff]

Still not right. I'll change carbs now.

[Jeff]

I ran the mill yesterday and cut to small red pine logs. Mill ran BAD while cutting.  THis morning I went out and changed the carb. I checked the oil and the level was good, but I think I detect the smell of gas.  I tried to start it, No fire.  Acted flooded.  I pulled the plug on the front side of the mill and it looked good, I pulled the plug on the back side and it looked good but wet. So, I decided I would crank the engine a couple times with the plug out. GOOD DANG thing I didnt have my face any closer. Must a blew at least an once of gas out.  Either that gas got in there last night after we shut it down, or it accumulated in the last cut or so when the engine felt like it was running on one cylinder.  You would think it would get sprayed out the exaust, but I guess, as liquid, how can it? Muffler goes straight up. 

As soon as I blew that stuff out of the cylionder and put the plug in it fired right off. I am going to go out and saw another log in a bit. Hope its better. Dont know what else it could be now if it aint. Different fuel pump and different carb.

[Coon]

Well,  for all of those who are wishing for rain......hmmm...... come and get some.  We have had by far more than needed.  95% of the crops here are still out in the field and we have yet been able to pick them up.   On a normal year we would be nearing the 60-75% finished point but not this year.  We can't even swath alot of the crop that is in the low spots cause they is full of H2O.  In the past month or so we have had atleast 15 inches of the wet stuff.  Getting kinda depressing.   Especially when our barley that should have went malt is now only of feed grade because it has sprouted.

[Jeff]

Stopped to grab some late breakfast.  MUCH BETTER! I think the problem is solved knock on wood.

[woodbeard]

well, here's hoping you end up with plenty to knock on! 

[ladylake]

Jeff  Hows that Onan running?  Steve

[Jeff]

Its really running well. It was all in that carb somewhere.  I may pickup a kit for it and rebuild it so I have it on the shelf.

[WH_Conley]

Local dealer told me the only kit for the carb was a "bowl kit" float, needle valve and keeper pin. $85.00 later and no improvement at all.