Freaking out a bit: 312-8 with a Kohler K301 engine has fuel in the oil?

[Alrashid2 171]

Hey guys, a bit scared here and hoping someone can give me some advice... earlier I noticed my oil seemed to be a bit overfilled based on my dipstick. Figured I didn't notice when changing the oil last week and decided to just drain a bit out.

Well, this oil is only a week old, and it came out with a pretty high viscosity, almost like water rather than oil, and wreaked of gasoline. Definitely fuel making it's way into the engine oil for some reason.

 

Does anyone know how this could happen on a Kohler K301 engine? How can I fix this? I assume this is definitely not good. She starts and runs fine, no trouble at all, so I don't think it's a carb issue. Could the only other culprit be the fuel pump? Thanks guys for your advice here

[ri702bill 8,387]

Ruptured diaphragm on the fuel pump. Oil is now contaminated & must go. Repair or replace fuel pump first.....

[Alrashid2 171]

Thank you for the reply - that isn't too hard a fix right! I think I can get a new pump cheap.

 

When I remove the old one would it be obvious that it's the culprit?

[ri702bill 8,387]

Maybe - disassembling the pump will tell the story. "Cheap" plastic pumps are only a short term fix...

[Alrashid2 171]

10 minutes ago, ri702bill said:

Maybe - disassembling the pump will tell the story. "Cheap" plastic pumps are only a short term fix...

Thanks. I'll see if I can source an OEM pump

[rjg854 11,393]

Just rebuild the one you have. They're not that complicated if it's the metal one.

[Alrashid2 171]

Just now, rjg854 said:

Just rebuild the one you have. They're not that complicated if it's the metal one.

Unfortunately I have a plastic one, so thinking it was replaced at some point?

[953 nut 55,394]

All of my workers and customs have electric fuel pumps for two reasons, they work better and they can't contaminate my oil. With gasoline contaminated oil ti wouldn't take long to begin excessive engine wear.

A new electric pump will cost about the same as a rebuild kit and will work much better.          

[oliver2-44 9,787]

27 minutes ago, 953 nut said:

All of my workers and customs have electric fuel pumps for two reasons, they work better and they can't contaminate my oil. With gasoline contaminated oil ti wouldn't take long to begin excessive engine wear.

A new electric pump will cost about the same as a rebuild kit and will work much better.          

I rebuild the metal pumps to keep older horses and other color tractors closer to original. But workers go electric. 

[Alrashid2 171]

Thanks guys. I'll consider the electric pump replacement but is it overly complicated compared to just swapping mechanical pumps? I'd like to keep this simple if possible. Any resources out there? 

[Bill D 1,927]

I built a mounting plate and switched to vacuum impulse pumps.  If you go this route, purchase a name brand Briggs or Kawasaki pump.  They are made by Mikuni in Japan.

[Alrashid2 171]

Thanks for sharing, you did a nice job!

 

Reading over some posts, the electric pump seems a bit beyond me. I'm short on cash at this point too and would like to just replace with a plastic fuel pump. Hell, if it goes bad, they seem cheap enough and the install doesnt seem too difficult

 

Does anyone know of a source for a mechanical fuel pump replacement? Ton on amazon but I rather buy from a more reputable source if possible

[Bill D 1,927]

17 minutes ago, Alrashid2 said:

Thanks for sharing, you did a nice job!

 

Reading over some posts, the electric pump seems a bit beyond me. I'm short on cash at this point too and would like to just replace with a plastic fuel pump. Hell, if it goes bad, they seem cheap enough and the install doesnt seem too difficult

 

Does anyone know of a source for a mechanical fuel pump replacement? Ton on amazon but I rather buy from a more reputable source if possible

Thanks.  You can get OEM pumps off Amazon for about the same as aftermarket mechanical pumps.   They are much more reliable than the aftermarket mechanical pumps.  Those too are known to leak gas into the crankcase.  The plate is easy to make.

[Alrashid2 171]

Thanks for the pictures. I think I'd like to KIS and go with a mechanical like-to-like replacement.

 

Took the fuel pump off my engine. It is definitely a cheapo aftermarket plastic one. No branding or part number anywhere on it.

 

Took it apart. What bothers me though is I'm not seeing any tear in the diaphragm. So not sure how so much gas leaked into the crankcase? Just drained the oil too - super rough estimate here but it looks like half a quart of fuel in there! (drained 2.5 qt).

 

Does anyone know of a mechanical pump replacement source? I can't justify spending $200+ off the Kohler website, but also can spend more than $12 on Amazon... 

[Alrashid2 171]

Reading some older posts and looks like the Rotary brand pumps are considered good? Can anyone confirm if this would fit my Kohler K301? Looks the same as what I pulled

 

https://www.rcpw.com/rotary-16833-fuel-pump-for-kohler/?srsltid=AfmBOor8liBfKBYpuvBQhrpe1eLBlChjxcj622FI_FtCiXF2ljF7YXl2

[Ed Kennell 38,329]

2 hours ago, oliver2-44 said:

But workers go electric.

Same here.    No chance to contaminate the oil and if they are located below the fuel tank, no need for primer bulbs or valves to prevent fuel drain back.

Batteries and starters will thank you for the instant starts.

[oliver2-44 9,787]

2 hours ago, Alrashid2 said:

Thanks guys. I'll consider the electric pump replacement but is it overly complicated compared to just swapping mechanical pumps? I'd like to keep this simple if possible. Any resources out there? 

 

Very simple. One hot wire to the key switch and pump grounds to frame.  Take the rear fender off and mount the pump back under the tank or in the tunnel area.  You can make a cover plate for where the mechanical pump was, or just leave mechanical pump in place.  They cost less or about the same as the Rotary mechanical pump you posted.  I' not at home, so I don't have any pump names/numbers this evening.

[953 nut 55,394]

Read through this post, it should give you all the answers you are looking for.  The wire going to the volt meter on your 312 is fuse protected, turns on and off with the ignition key and is easy to get to, this is a good power source for the electric pump.

 

[Alrashid2 171]

Thanks guys. I might be making a mistake here but I found the Rotary brand plastic mechanical pump for 50 bucks and bought that... will monitor and should this one fail too, I'll learn my lesson and do the electric pump in the future. Thanks for the resources guys

[Alrashid2 171]

Hey guys, can I ask what other things could cause gas to get into the oil?

 

I read a post on here where many suggested it could be the carb, but wasn't sure if that applied to my case. I did check my bowl and the float seemed to move up and down just fine.

 

Could someone tell me what else I can check to rule out the carb? I'll be replacing the pump but I hate not knowing for certain if that was the cause since I didn't see any holes or rips in my current pump diaphragm. For peace of mind I'd like to rule anything else out 

 

Thanks for the advice 

[Maxwell-8 4,277]

5 hours ago, Alrashid2 said:

Hey guys, can I ask what other things could cause gas to get into the oil?

 

I read a post on here where many suggested it could be the carb, but wasn't sure if that applied to my case. I did check my bowl and the float seemed to move up and down just fine.

 

Could someone tell me what else I can check to rule out the carb? I'll be replacing the pump but I hate not knowing for certain if that was the cause since I didn't see any holes or rips in my current pump diaphragm. For peace of mind I'd like to rule anything else out 

 

 

 

Take of the bowl and fuel hose. Now blow compressed air (low pressure) into the carb. Meanwhile moving the float up and down.

When the float is level it should stop letting air trough. 

 

Could it be the intake valve shaft is little worn? letting vaporized fuel/air into the crankcase?

[953 nut 55,394]

8 hours ago, Alrashid2 said:

Hey guys, can I ask what other things could cause gas to get into the oil?

 

I read a post on here where many suggested it could be the carb, but wasn't sure if that applied to my case. I did check my bowl and the float seemed to move up and down just fine.

 

Could someone tell me what else I can check to rule out the carb? I'll be replacing the pump but I hate not knowing for certain if that was the cause since I didn't see any holes or rips in my current pump diaphragm. For peace of mind I'd like to rule anything else out 

 

Thanks for the advice 

Your engine was running fine before the fuel was discovered in the oil, right? Don't make this more complicated than it needs to be.

Take a look at the location of your carburetor in relation to the engine block. Think logically, If excessive amounts of fuel were present in the carb. would it run up hill through the intake valve which is closed more than 70% of the time and then down past the piston rings        or would it just gravity flow out of the carb. at the air intake.

[Alrashid2 171]

4 hours ago, Maxwell-8 said:

 

Take of the bowl and fuel hose. Now blow compressed air (low pressure) into the carb. Meanwhile moving the float up and down.

When the float is level it should stop letting air trough. 

 

Could it be the intake valve shaft is little worn? letting vaporized fuel/air into the crankcase?

Thanks guys for your responses! Unfortunately I don't have compressed air here but thinking maybe I can just blow into the fuel line right?  I'll give that a shot here today

I'm not as familiar with carb lingo as I should be at this point... is the intake valve shaft inside of the carburetor? Is that the same as the needle seat that is supposed to shut when the float raises? 

51 minutes ago, 953 nut said:

Your engine was running fine before the fuel was discovered in the oil, right? Don't make this more complicated than it needs to be.

Take a look at the location of your carburetor in relation to the engine block. Think logically, If excessive amounts of fuel were present in the carb. would it run up hill through the intake valve which is closed more than 70% of the time and then down past the piston rings        or would it just gravity flow out of the carb. at the air intake.

Fair enough, just wanted to make sure I don't have a bad engine on my hands. Yup, it ran perfectly: starts up perfectly, runs perfectly, no stalls or rough idle or anything like that. 

 

Maybe I don't understand fully how a carb works, but isn't there a suction function in this equation, that is pulling gas up from the carb to the intake? I guess that's why I thought maybe it was going into the engine

[Alrashid2 171]

UPDATE: pulled the carburetor, and checked the float and needle seat. Everything looked clean and to be in working order! Blew air into the fuel line, and air flow stopped when float raised. If anything, the needle seat was sticking shut a bit. Cleaned it with a bit of brake cleaner and no more sticking, but obviously that wasn't the issue.

 

I'm thinking at this point it's safe to assume if I have a new fuel pump, and the carb is good, then those are the only 2 ways fuel could have been getting into the crankcase, right? 

[oliver2-44 9,787]

11 hours ago, Alrashid2 said:

I didn't see any holes or rips in my current pump diaphragm.

 If your pump diagram had a tiny pinhole that leaked a tiny drop every engine rotation, let’s say average 2400rpm. The fur pump moved every engine rotation so that would be 2400 tiny drops a minute. That would be 144,000 tiny drops in an hour run time.