How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Delsley Jr Your Own Question
Delsley Jr
Delsley Jr, Mechanic
Category: Small Engine
Satisfied Customers: 689
Experience:  Handyman & Small engine repair Business owner
Type Your Small Engine Question Here...
Delsley Jr is online now
A new question is answered every 9 seconds

Hello, My neighbor has a generac generator with a GT-990 engine-

Customer Question

Hello, My neighbor has a generac generator with a GT-990 engine- after taking off the air cleaner cover I noticed the inside of the air filter and the air filter itself were covered in oil including most of the engine itself. One of the hoses for the oil cooler was leaking a small amount of oil, but that didn't account for the rest of the oil in and around the engine compartment. Any ideas? Thankyou
Submitted: 7 years ago.
Category: Small Engine
Expert:  Jon K. replied 7 years ago.

The first thing I would check is the oil level. If it is overfilled, the excess will be blown out the breather and into the air filter. Also if the machine is moved around and tipped so that the air filter is downhill the same thing will happen. Clean out the air box, replace the air filter with a clean one and make sure your oil level is correct.

And fix the oil cooler line, or you may run the chance of seizing the entire engine if the oil runs too low

Customer: replied 7 years ago.
Relist: Inaccurate answer.
Expert:  Delsley Jr replied 7 years ago.
HiCustomer... Does the engine start and run ok ? Does it smoke out the muffler when running ?
Customer: replied 7 years ago.


The Engine seems to run fine . It doesn't start on the first turnover but it runs well. There is no smoke that comes out of the exhuast. I have some experience with engines and have checked most of the symptoms that make some kind of sense as to what might be wrong without taking apart everything.

The oil level is actually on the lower side [it doesn't need oil].

I haven't been around when the engine has run for any length of time that is over an hour or so.


Expert:  Delsley Jr replied 7 years ago.
Ok four-cycle engines include a crankcase breather connected by a flexible line to the carburetor intake. The filter element, in conjunction with a baffle, separates liquid oil from blow-by gases, which then recycles through the carburetor. The reed valve maintains a slight negative pressure in the crankcase to reduce seepage past gaskets and crankshaft seals. If the filter clogs or the valve becomes inoperative it could cause some of the problem your having with it.