Smoking 312-8

[Ed Fox 20]

Hello everyone. I have a 312 with the CI Kohler. 700hrs. I'm burning through about a 1/3 to 1/2 qt of 10-40 with about 2 hrs of hard running. You recently directed my to remove the balance gears and with that said when I had it apart the inside of the engine is clean, not gunked up.  I'm by no means a small engine tech but ive been working on machinery for the better part of my adult life and after buying a farm 2 years ago I've had my share of small engine repairs the last two years. I'm wondering if this engine with 700hrs is worth rebuilding (keep in mind if you say rebuild I'll most likely be in your a$$ on here daily asking questions 👍) or should I just look at after market replacment options? 

 

Thank you for your direction. 

 

Ed

[oliver2-44 9,683]

What year is your 312, I'm not sure what your refering to as a Cl Kohler.  

If it had balance gears I'm going to speculate its a K-Series.   The K-Series and Magnum Series Kohlers are definately worth rebuilding.  Usually that means having the cylinder bored oversize, and possible having the crankshaft ground undersize.  There are a (slim) few instances where you might get by with honing it and replacing rings and a valve job.  In most cases the bore has worn itself egg shaped and honing won't fix that.  There's lots of friendly help on here to walk you through an overhaul.  

But lets backup a minute, tell us more about it using oil.  Is it smoking (white or black) under load?   Does it smoke bad on startup, then clear up?   

Edited July 16, 2020 by oliver2-44

[Ed Fox 20]

Hi Oliver. It's a mid 80s model. Cast Iron (CI, sorry. Using CI is a cast iron pan reference) the smoke is black and most visable when you throttle up or down and/or put it under load as dropping the PTO in then  the visibility of the smoke fades but if you watch the exaust you can see it faintly now and then. 

[rjg854 11,349]

Try using a straight weight oil, as recommended by Kohler during the warmer months like 30w.  See if that doesn't help with the smoking issue before you tear anything apart. You say you're using 10-40 , they call for a multi-grade for colder weather.

[SylvanLakeWH 25,490]

[953 nut 55,074]

A Kohler engine with only 700 hours of operation on it shouldn't bee in need of a rebuild if it has had regular oil changes every 25 hours of operation. As Randy said, you should be using 30 rather than 10 W 30. Also, be sure you are not overfilling the oil.

[Ed Fox 20]

I'll switch over to strait 30. Should I use a non detergent?  Definitely not over filling it. 

Thanks!

[953 nut 55,074]

3 minutes ago, Ed Fox said:

Should I use a non detergent?

Detergent oil is fine.

[SylvanLakeWH 25,490]

Lots of different opinions on this issue...

 

I use Shell Rotella T1 30 w. per past advice from some folks on this forum and it has worked well. But, I am no expert. I also change the oil more than "required" or recommended...

 

Has worked well for me.

 

[peter lena 8,580]

ED FOX ,  hello ed , i have used RISLONE  ENGINE TREATMENT ON  a number of used engines  https://www.walmart.com/ip/Rislone-Ring-Seal-Smoke-Repair-16-oz/22269732?wmlspartner=wlpa&selectedSellerId=101002903&&adid=22222222227016838564&wl0=&wl1=g&wl2=c&wl3=52919137511&wl4=pla-84839958431&wl5=9003292&wl6=&wl7=&wl8=&wl9=pla&wl10=136582778&wl11=online&wl12=22269732&veh=sem&gclid=EAIaIQobChMIv5rAoNbR6gIVA-21Ch12LQV0EAQYAiABEgJNXvD_BwE  the cleaning and make up , very quickly turns , oil to dark , telling you its cleaning. do this over a couple of hot oil changes , it has really worked for me , oil alone will not do it. i agree with a 30 wt oil, i use rotella .  pete

[The Tuul Crib 7,336]

T1 30 Rotella has zinc which is good 

on the internal parts as well as a blend of 

detergents. I run it year round here. Of course I'm in the Midsouth so we don't get all that cold in the winter.

[Rob R 966]

Take the head off and see if the piston moves from side to side the last Magnum 10 I rebuilt had 40 > 50 thousands ring gap yet the cylinder was within the Kohler manual Maximum bore specs.  I honed the cylinder put a new set of standard rings with a new piston. Prior to the rebuild the engine was blowing black smoke and actual carbon out the exhaust. I cut my 1.5 acre property for the last two years with this 310-8 it starts and runs beautifully with no smoke and full power. The K series engines are amazing.... change the oil every 25 hours will run a lifetime + 

 

[oldlineman 1,481]

Yea all of that I also use Rotella 30w very good oil, remember good oil is cheaper than parts!

[Ed Fox 20]

Thank you everyone. I'll pick up the oil this weekend and give that a shot. I bought the tool to do a compression test but have never done one. If the oil doesn't make a fair amount of improvement I'll figure the compression test tool out and report back. 👍

[JAinVA 4,619]

You may not get a lot out of a compression test on the Kohler.They have an ACR (automatic compression release ) during start up so cranking the engine will not give you an accurate  result.

[pfrederi 17,664]

The owners manual specifically recommends AGAINST 10w-30 above 32 degrees.  Noting Excessive oil consumption....

 

 

[bottjernat1 2,190]

What a topic oil. LOL Here is my 2 cents I use SAE 30 in my older air cooled machines just like my late dad did. And i use it all year around. He never had issues and either have I. Here is a photo of what exactly i use. 

[tom2p 2,394]

22 hours ago, Ed Fox said:

Hi Oliver. It's a mid 80s model. Cast Iron (CI, sorry. Using CI is a cast iron pan reference) the smoke is black and most visable when you throttle up or down and/or put it under load as dropping the PTO in then  the visibility of the smoke fades but if you watch the exaust you can see it faintly now and then. 

black smoke ?

 

black smoke might indicate another issue - in addition to other possible issues ?

 

compression check would be good idea 

 

 

regardless of the manual warning - if engine is burning 1/2 quart in two hours - I doubt a switch to 30w from 10w40 will make an appreciable difference 

 

( given both oils are similar / decent quality and not broken down )

 

 

I have an early 90's 312-8 with around 800 hours - owned it since late 1990's

 

I've used 10w30, 10w40, 5w30 in this tractor since I've owned it (synthetic) ;  it uses almost no oil  

 

 

Edited July 17, 2020 by tom2p