[rustyknuckles]

The Onan in my 318, running my 49 snowthrower, has been running poorer and poorer. I have a Kohler replacement engine to install next Spring/Summer, but I have to keep the Onan operational until the worst of the snow is over in Massachusetts. (the Onan has less than 500 hours on it)

Anyway, it is running very lean and requires a fair amount of choke to run smoothly. Just today, it started surging and stumbling and backfiring. Until recently, it was idling poorly, but today it wouldn't idle at all.

It would be nice if there was just "gunk in the carburetor." But the tractor is really only operated in the winter, when there is minimal dust and dirt in the air. What I'm hoping is NOT the case, is that I have a leak at the intake manifold. The tractor is in an unheated barn, so engine work is not too much fun.

Anyway, can anyone suggest the best way to diagnose what is most likely wrong, without tearing the carburetor completely apart?

Thx.

 

[wmgeorge]

I suggest doing a little searching and reading about your problem. Comes up about every three days or so....
You more than likely have either bad or dirty gas, Or gunk in the carburetor that is making it run lean.

 

[trapperjohn]

Jay, Because you said it needs choke to run smoothly, I'm thinking clogged jets. This can happen from the fuel lines breaking down from the inside and ending up in the main jet or the idle jet. It happens to be easy to check. Take the top off the carb to get to the idle jet and the plug on the side to get to the main jet. I hope this is your problem.

 

[dkarst]

Good ideas above but I'll add my problem with these symptoms was not intake manifold leak but intake gasket leak. I would recommend a quick check with UNLIT propane torch around manifold area to see if smooths out.

 

[knottyrope]

with ethanol gas the aluminum corrodes and makes a sand like stuff in bottom of bowl. yoru fuel pump may have some of this crud in it too. also check the 90 at the carb. once all clean start using a lil 2 stroke oil in the gas to keep parts covered in oil. I have not had this issue in years now.

 

[rustyknuckles]

Knotty -
How much is a "little bit" of 2-stroke oil?

 

[knottyrope]

I put in a few ounces per 5 gallons.

this puts an oil film on carb surfaces so it wont corrode

 

[boomers_influence]

jay
i WONDERING WHY you would
replace an engine with 500 hours on it???
thank you. boomer

 

[akaothermick]

Wondering the same thing myself, Boomer??

 

[rustyknuckles]

robert -
1) The B43G really needs to have more oomph to move the heavy New England snow. It almost stalls out at times.
2) I got a pretty good deal on a 27 HP Kohler V-Twin
3) I must have too much time on my hands ! (I also have a 420 two speed rear end to install, as well)

I'll probably sell off the Onan when I get the new engine installed sometime this year.

 

[knottyrope]

if running lean then that's why you have no power

my 420 running lean didn't have much power and stalled when putting on the PTO in low RPMs

 

[wmgeorge]

There is kind of a trade off with more power vs traction when moving snow. All the Hp won't do much good when you can't get the machine moving in the snow.

 

[rustyknuckles]

I have two 75 lb wheel weights and two suitcase weights on the rear, plus chains. No slipping that I can tell. But the heavy snow will definitely bog down the thrower, especially the glop at the end of the driveway. Of course, a two-stage would work better, but that would be big bucks. When I re-engine, I will change the gear ratio to spin the auger faster, as well as putting on rubber flaps on the edges of the auger center. But need to nurse the Onan along for now!

 

[austin_brothers]

Not really related to hydro's but my 210's been doing the same when I hit the PTO

 

[wmgeorge]

Jay it sounds like you are on track for the more power upgrade, I was thinking you had a blade. You guys have been hit hard this winter also, so I understand the, just make it through this winter!

Austin You Need to start another Thread to get help with your 210 problem.

 

[michael l.]

I put the rubber flaps on the 49 and they lasted 1 day in my dirt, gravel driveway.
I used the baler belting from TSC.
Now the 34 tooth sprocket seems to be doing a good job.

 

[rustyknuckles]

To Ron Haass -

Can you actually get the main jet out, with the carb on the tractor? I can see getting the cover plug off, but then what?

 

[knottyrope]

most jets can be taken out with a flat screw driver, just make sure you get largest one that fits it very well and not too small as brass can deform easy.

 

[trapperjohn]

Jay, Once you have the plug out you need to use a 5/16 screwdriver bit with a 5/16 box wrench and then you can get it out. You may have to grind the bit to length for it to fit and then keep it just for this use. Look at my first picture and you will see what I am talking about.

 

[wmgeorge]

And Stuff rags under the carb so when you loose either a jet or screw it does not roll under the manifolds.