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View Full Version : rebuilt kohler, still blowby


97firebird
05-10-2005, 12:59 AM
Ok guys, here I am again..I posted not too long ago saying how I rebuilt my kohler magnum (92-93 model) anyway, i put new pistons, rings, cylinder hone, valve job, replaced bad valves, new gaskets..the whole thing. There is still a lot of oil getting blown past the rings somehow through the breather system and up into the air filter. There must be a reason for excessive positive crankcase pressure or something because the cylinder bore and rings are brand new and i had the guy at the shop make sure the cylinder was not oversized for a stock sized piston. Therefore, why am i getting excessive blowby and leakage out of the breather valve cover? I believe the breather is working correctly, not clogged either, and is installed correctly, is there anything else that can cause this? Could it be valve guides/seals? This motor has been torn apart three times already trying to fix the problem and I am ready to light a match! Any help would be greatly appreciated. Thank You.

Restrorob
05-10-2005, 07:06 AM
It still sounds like a breather problem,I see now your mag. has a different style breather than i mentioned in your last thread. If you havn't done so take the breather assembly apart, Inside you will find a umbrella valve part# 52-462-01 and a hose type seal part# 52-032-04-S Replace both these with new gaskets part# 52-055-01-S . Post me your full model & spec. numbers and I will check for any old service bulletins for this problem.

97firebird
05-10-2005, 09:33 AM
Model # is MV20S
Spec # is 57520...(cant read rest)
Are you saying that the valve could be bad or that cylindrical gasket/tube could be no good? The valve just consists of a hole in the plate with a plastic flap sitting over the top of it. When I pull it away from the hole and let it go it snaps right back. Doesn't seem like there could be much that goes wrong with it. You could be right, but I dont want to keep replacing parts and not fixing the problem. However, i appreciate the assistance.

Restrorob
05-10-2005, 08:07 PM
I'm sorry I havn't helped you solve this problem yet. Had I been able to see or touch this engine I'm sure the problem would be solved by now,But all I can do is give you my thoughts as to what could cause this problem.
I did find a service bulletin on this spec. engine,But I must download Adobe Reader on my computer to read it I will do this later tonight.
In the mean time I went to the good old service manual and went to trouble shooting and the only thing I don't think has been checked is the muffler.
The baffles break loose from vibration it could restrict the exhaust flow and cause this problem.
There isn't anything I hate worse than letting a engine problem get the best of me,I will keep trying if you like or I'll give up.
Soon as I read this bulletin I'll post back if you like !

97firebird
05-10-2005, 10:27 PM
I am very happy someone is trying to help me out, so thank you...I didn't mean to negate your inputs, but I am trying to get as many possibilities as possible so that I can weed them out. Today I was told by a mechanic that it is probably the pressure release valve. well, this is simply a ball held against the bottom of a hole within the crank case by a spring. So, i pulled the motor once again, pulled the oil pan off, and looked at it...the only thing i can see wrong with it is that the spring has got some nicks and marks in it. Other than that, we blew air through it and it didnt seem to be clogged with anything. The same mechanic also said that it could be the valve seals leaking oil into the cylinders. I think that I am going to have to get a leak down test done. This will atleast tell me where the oil is comming up from. My worries are that I am going to replace those and it wont solve the problem. Then there is the other question as to whether or not there is too much positive crank case pressure causing excessive blowby...but what else would cause this besides a faulty breather system or oil pressure release valve? Beats me. Thanks again.

97firebird
05-10-2005, 10:28 PM
oh yea, as to the muffler...i blew through it with my mouth once before and it flowed well, so I think I am all set there.

Restrorob
05-11-2005, 12:30 AM
Maybe This will do it.

97firebird
05-11-2005, 11:06 AM
This shows the way I have it set up, but I am wondering if there is a new style newer that the reed style valve I have...I am thinking I might as well just replace the entire system just to make sure.

Restrorob
05-11-2005, 12:50 PM
This shows the way I have it set up, but I am wondering if there is a new style newer that the reed style valve I have...I am thinking I might as well just replace the entire system just to make sure.


If there was a even newer style it would have came up on the S. B. web site they post all on there. I like the idea of a cylinder leak-down test, I didn't say anything about it because the average person doesn't have the proper equipment to perform this test but it would tell the whole story as to how things went together. Please keep me posted as to what the outcome is.
SEE YA !

97firebird
05-11-2005, 02:10 PM
ok, i am waiting on a crankcase pressure relief valve and new valve seals...I have already bought the new breather valve and tube gasket. Once I get the valve seals I am going to bring the motor down to the shop and get the leak down test done. I am pretty sure it is going to reveal that the valve guide seals are going to be shot. Therefore, the motor will already be at the shop and I'll just have them replace the seals. If not, everything else that could be the problem should be taken care of when I put it back together one last time. I will let you know how it turns out. Thanks for all your help.

Restrorob
05-11-2005, 06:06 PM
Thanks I'll wait to here from ya !

briggsman65
09-05-2005, 08:25 PM
I wonder if he offset his rings?

lawnmaniac883
09-05-2005, 08:34 PM
Must be one slow mechanic...four months and still no repair lol. I guess his problem was solved.

Dirty Water
09-05-2005, 08:39 PM
What is the break in period for rings to properly seat?

Restrorob
09-05-2005, 09:25 PM
What is the break in period for rings to properly seat?

50 Hours according to Kohler Tech support, But I believe they break in sooner than that.

phuncadelic
08-04-2006, 10:56 AM
[QUOTE=Restrorob]umbrella valve part# 52-462-01 QUOTE]
I am looking for that exact part! my Tractor is down until I can find one. From everything I have found online they are discontinued. do you have any ideas how I could get my hands on one?
THANKS!

Restrorob
08-04-2006, 12:14 PM
[QUOTE=Restrorob]umbrella valve part# 52-462-01 QUOTE]
I am looking for that exact part! my Tractor is down until I can find one. From everything I have found online they are discontinued. do you have any ideas how I could get my hands on one?
THANKS!


That number has changed to 52 035 02-S and is now the complete breather assembly. You can purchase it here if you like; http://search.cartserver.com/search/search.cgi?cartid=a-8671&category=Kohler_Parts&keywords=KOH-5203502S

phuncadelic
08-04-2006, 12:32 PM
Restrorob
Thanks so much! i thought I would have to junk this thing. I wish some of the guys around here were as helpful! I owe you one :drinkup:

Restrorob
08-04-2006, 07:22 PM
I owe you one :drinkup:


How about a seven http://www.gtr-game.com/forums/style_emoticons/default/burp.gif http://www.gtr-game.com/forums/style_emoticons/default/shiny.gif

phuncadelic
08-11-2006, 10:08 AM
ok I recieved that part but I think I need a new float in the carb. what happens is:
when the carb is completely dry, I start the engine, it will run really hard and I usually end up shutting it off, then it will not start again and I look in the carb and it is full of fuel, it wont start again until the fuel either evaporates or I empty it.
when I look at the float mechanism, I cant tell how it stops fuel from coming in. Is there supposed to be a plug-like-thing that plugs the hole when the float fills up?
Hope this make sense.
Kohler m18s with a Walbro Carb
Thanks!

Restrorob
08-11-2006, 12:15 PM
Is there supposed to be a plug-like-thing that plugs the hole when the float fills up?


Yes, There is supposed to be a float needle valve under the float so as the bowl fills up to the proper level the float pushes the needle valve up in the orifice and cuts the fuel supply off. If this needle valve is missing or bad it will cause the engine to flood as it's doing. Once a new needle valve is installed hold the carb. up side down (with bowl off) and eye the float, It should sit level with the bowl gasket area. If not bend the little tang that contacts the needle until it's level.
Also check the float for fuel inside (pin hole) by shaking, If fuel is inside you will feel it. If there is replace both the float and needle valve.

phuncadelic
08-11-2006, 01:39 PM
Great thanks. :drinkup: thats 8!
I'll let you know if I am able to screw something else up.

phuncadelic
08-11-2006, 07:51 PM
ok I found the needle for the float. starts great after about 5-10 seconds it starts burning oil. I take the air filter off and watch the oil just bubble up in to the air filter. :hammerhead:
Any ideas?

here is what the breather assembly looks like

to air filter
|
____O
XXX -mesh wire
O\_____
|
to pistons ?

thanks for the help

Restrorob
08-11-2006, 09:36 PM
Didn't quite understand your pic. but here's the procedure from the service manual, Make sure the part in red is the way you installed it. Sorry for the bad pic. but I had no control they are all that bad.

Also check your oil for fuel contamination, It could be over filled with fuel from the carb. flooding.

phuncadelic
08-14-2006, 03:33 PM
OK I drained all the oil which of course smelled like gas. put 1 1/2 quarts backs in runs and NO oil blowing into the airfilter.
Next problem....
runs very high RPMs I got the adjust the idle screw and it will idle fine put as soon as I tap the throttle the ROMs jump way up I dont even take it above half way.
Any ideas?

Thanks again!

Restrorob
08-14-2006, 04:35 PM
Any ideas?


Now you should know by now I'm full of um. :cool2: And your gonna keep on and get me drunk. :laugh:


You need to adjust the governor for starters and see if that solves the problem, Procedure below.

ChadsLawn
08-14-2006, 06:08 PM
Rob my kohler did the same thing ch22. It wass the gears in the engine that was broke. I bet his is broke also. Time to take the engine apart again. I hope thats not the problem with yours though.

Restrorob
08-14-2006, 07:55 PM
Rob my kohler did the same thing ch22. It wass the gears in the engine that was broke. I bet his is broke also. Time to take the engine apart again. I hope thats not the problem with yours though.


If you are speaking of the governor gear, Thats why I suggested adjusting first. The old Magnum engines had a much better made governor than the Commands so here's hoping that isn't the problem with his.
Now if you are going on your third governor gear you need to find out why it's eating them, I have Commands out in the Field clicking 2000 hrs. and never been into.
Just something to think about ha....:confused:

ChadsLawn
08-14-2006, 08:01 PM
nope just the 1 gear... Runs great now after the new heads and rebuild.

thecrankshaft
08-15-2006, 10:47 AM
You'll know the governor gear is working if force is exerted on the governor arm when engine speed increases.

phuncadelic
08-15-2006, 11:07 AM
I am guessing that is the problem. I remember watching the arm move "automagically" but now it is not doing that. now there is no force on the governor arm. How hard is it to replace the governor gear? :hammerhead: :cry: what a freakin domino effect this all happened because I put in bad gas....

Restrorob
08-15-2006, 11:57 AM
Did you try to adjust it ?

phuncadelic
08-15-2006, 11:59 AM
not yet.. I will definately try that first though