691 Hours on my 312-8 How mny more?

[jeff lary 171]

  I understand this is really an unanswerable question so maybe your opinions. I have a 1995 312-8 with 691 hours on it as of today. In your experience how many hours are these engines good for ? I mow in the summer and snow blow in the winter. How many hours can  these Kohler's take before you need to rebuild them? She runs just fine I take good care of it , it has never spent the day or night outside it is always under cover. I change the oil each spring clean off the foam pre-filter a couple times a summer and I keep it greased well. Fresh gas with Sea-Foam every few tanks like wise with Marvel Mystery oil too. How long can I expect before she fails me do ya think? Thanks Jeff

[slammer302 2,154]

2000+

[AMC RULES 36,945]

  Unlimited top end.  

[jeff lary 171]

Really?? Wow... providing your not nuts, and I'm not drunk that sound pretty great !

[tunahead72 2,341]

Jeff,

I would personally change the oil a little more often, maybe one more time in the summer (with 30 weight oil, I think) and again in the late fall or early winter before you start blowing snow (10W/30?), then back to 30 in the spring.  Make sure you take care of the other normal maintenance chores on this engine too, new spark plug once a year, fresh gas, check the points every once in a while, keep the carb clean and adjusted, that sort of thing.  Your Kohler owner's manual will have all the details.

[jeff lary 171]

Yes I will and do, Right now I am running 5w30 in it the temperature range seems to fit well enough. I have been running 5-30 since the early spring so far so good. I intend to run it in the engine year round I think. Does that 12 hp have points ? it is a 1995 machine I assumed electronic ignition ?

[Racinbob 10,277]

You're just getting it broke in  
Magneto on that one.

[chinoman279 10]

Jeff, as long as you are doing the routine maintenance - oil changes being the major one, that engine is still young.  I have an 89 or 90 312-8 that my father bought brand new and it has right around 4300 hours on it.  Top end has only ever been off it once to inspect and clean carbon about 15 years ago.  I have bought and sold many horses and I still think the magnum 12 is the best motor I have had on all of them.  Taking into consideration power and fuel consumption.  It is still my favorite horse for a worker.

[tunahead72 2,341]

... Does that 12 hp have points ? it is a 1995 machine I assumed electronic ignition ?

​

Magneto on that one.

​My bad, wasn't thinking.

[jeff lary 171]

I don't know how to answer each of you with out quoting each response ( some folks don't like to re-read ya know) So here goes. Bob ,Just broke in sounds good to me. Chinoman, 4300 hrs wow sounds good to me my engine does run good ! Tuna, there are many models it would be easy to confuse one with the other for sure.
So I think the carb bowl may solve the issue but I will ask anyway. When just driving the tractor without the PTO engaged at the high end of the throttle there is a slight roughness to the engine a little "putt pa paaa papa putt" ( how do ya like my sound effects?) sort of sound almost like a skipping . It has done this for many many years I am guessing maybe something in the bowl besides gas? Water dirt ect. Thanks for everyone's response's I have to leave for work now but I will check in later. Jeff

Edited June 15, 2015 by jeff lary

[Fordiesel69 213]

You can get 2000 ~ 2500 hrs if you run a diesel oil, changed often.  No longer does SM or SN oils have proper additives for flat tappet cams.  Diesel oils do.

So Shell Rotella T1 SAE 30, Mobil Delvac SAE 30, and Valvoline & chevron makes some.

During the winter Shell has a 10w-30 diesel oil.

-Warm up engine at 50 - 60% throttle, NEVER EVER at idle.  The dipper will never sling the oil to the cylinder, and you will create an oil burner in very short order.
-Operate at 100% full throttle during hot days so you get proper airflow.  Regardless of internet rumors you can operate a little slower when you are not loading it down much & overheating it.  But if you are mowing, run it wide open.
-Regardless of oil type, never ever extend the oil change beyond 25hrs.  These engines shred metal, and there is no way to filter it. 
-Fix & repair the throttle shaft busings in the carburetor.  These will loosen up around 700-800 hrs on a Walbro carb.  This is an instant source of dirt entering the cylinder. 
-Inspect every year the rubber hose going from the carb to the crankcase breather, these dry rot, or fall apart and also let lots of dirt in.
-Make sure to decarbon the cylinder ridge, this will eat the piston alive.  Attached is one that was never done.  It is now in need of a rebuild.  This needs done every 250-500 hrs.  I prefer to do it at 250 as you never know how bad it is until you look.  If done at 250 you can reuse the headgasket.  At 500 you should replace.
 

[Racinbob 10,277]

Not a bad Ed. I usually have to refresh my memory on which is which.
Jeff, don't over think things here. Your motor is still a kid in Kohler hours. Follow the owners manual for the maintenance schedule and recommended goodies and you'll be good for a long, long time. Personally, I do change the oil more often but I've always felt that keeping clean oil in any motor is just about the most cost effective thing you can do for it. In the 5+ decades of using Kohler motors I've never had an oil related failure and that includes countless hours of putt-putting around and just above idle. Use the heck out of it but reward it with proper service and both you and the motor will be happy.

[jeff lary 171]

  I always did change the oil spring and fall but last winter came before the oil change and I just did not change it till this spring. The oil in my motor is a funny thing, it is so clear that it is very hard for me to see it on the stick. It just never seems to get dirty . That is a wonderful thing though. I will change the oil this fall though I promise !!! As far as diesel oil I run Rotella T in my Kubota.The horse has Castrol 5-30 in it right now.
  Throttle bushings and breather tube hua... I will look at breather tube this weekend as far as bushings I guess I can see what model the carb is and see about ordering a kit + bushings for it maybe? She is all 100% Original It has had 2 batteries and 2 Solenoid's. Even the gas line in 1995 vintage ,...I know go ahead an flame me..... I did however install a new plug this spring and an inline gas filter. She gets a new plug every few years just because it is cheep I guess. But in many years of using all things with engines I have maybe had 2 plugs fail it is my experience they almost never wear out. You may foul one but,... clean re-gap and re-install works for me. 
 I am an awful critter for not messing with something that works but I am also all over it when it comes to preventive maintenance so... Clean the Carbon  from the cylinder hua, Well she may need it I don't really know .There is no sign of engine knocking or "run on" after the switch is shut off so I would not say there is a lot of glowing hot carbon inside keeping the combustion going when shutting it off so I am not really sure. I started using Sea Foam last winter and I believe that is supposed to reduce / eliminate carbon build up? But I am not positive on that either. I always run her at wot when working it when just traveling it runs at about 1/2 throttle though.

[Racinbob 10,277]

Sounds to me like you have a logical approach.  As far as the oil a looking clean, I have the same 'problem'. I guess I'll just have to deal with it. 

[jeff lary 171]

Well it is either clean or we are half blind either way It makes me grin !

[Racinbob 10,277]

That's it! 

[gsummers 236]

Over 1100 on my 1990 Magnum 12, keep the oil clean and the air filter clean, they will run forever.

[jeff lary 171]

I am liking all this but I do have a problem. I just looked at my thread title my "Mny" is missing an "a" as in "Many" can some one fix it? I hate to have all you fellas think I don't know any better..... Well actually I didn't  know any better till a moment ago.

[Racinbob 10,277]

Why....you big dummy!  I'm sure glad I never have a typo.

[Kipling79 1]

The Magnum 14 that I just purchased -> then blew up -> then rebuilt had either 1400 or 2400 hours on it, and was still running strong except for a severe oil-burning problem. So I would second everyone's opinion on religiously checking the breather tube.

I have attributed the oil-burning problem to a loose breather tube that allowed debris to be sucked into the intake and added to the wear of the cylinder. I found a thick layer of dirt/dust/debris a inside the air cleaner and an equally thick layer on the choke plate inside the carb. So, I would guess that many pounds of dust flowed through that engine over it's lifetime and caused the issues.

[jeff lary 171]

I will check the breather tube this weekend. I can say so far so good, I had the filter off a couple weeks ago and inside was scary clean the choke plate and intake throat were all spotless.
 I just got home I had to be at an interstate interchange 50 miles from home at 4 am so I took off a little early this afternoon. I run a Guardrail crew for the state and we had a repair to make where a truck went out through the rail on an off ramp last week. I guess the guys truck stalled on the way down the ramp and he lost steering.
 So when I got to the house I went out to my shop to get a saw ready for my son. I put a new Meteor Piston and Caber rings in it this saw this last winter along with a carb kit. I kept it on the Kubota so I could try it out some this  winter.
 Well the boy came over while we were away on a cruise this spring and couldn't find his saw,..so he took a different saw from the shop. If at all possible I like to keep him in the same saw this sampling dads goodies has to stop ya know !! I set up a trail camera pointing at the house while we were gone we got some new unsavory neighbors ...that's how I knew I was saw pilfered ! Gotta watch them young fellas ya know slippery they are quick too..

[jeff lary 171]

BTY how do I get a picture into the avatar box? I have tried a couple times with some pictures I have on the desk top in folders but I must be doing something wrong. Well I guess I figured it out but none of my pictures are small enough to fit here? I had to edit - re-size - crop to get it to fit. The Ranger was hauling a trailer full of split fire wood with my Brittney named Ranger waiting for a ride. All you can see though is the Ranger no trailer.

Edited June 16, 2015 by jeff lary