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The Small Engine Doctor
The Small Engine Doctor, Small Engine Technician
Category: Small Engine
Satisfied Customers: 81
Experience:  Over 30 years experience repairing & rebuiding 2&4 cycle engines, All brands and configurations
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I have a briggs model 28n707 type 0173-01. It came ...

Customer Question

I have a briggs model 28n707 type 0173-01. It came installed on a sears rider. It has ran well for years and I would guess it has about 700 hours on it. It has started using a lot of oil. It seems to use a lot less if I leave it on the fill line. If I keep it at the full line it smokes a lot going up a incline. It has started fouling the plug. Is there a crankcase vent that I am missing? I can''t understand why it would use oil after only 700 hours.
Submitted: 8 years ago.
Category: Small Engine
Expert:  The Small Engine Doctor replied 8 years ago.
HiCustomer This is Dave, The Small Engine Doctor. No, I dont think your missing anything. There is a crankcase ventilator (sort of like a PVC valve) directly under where the intake and exuast manifolds enter the engine. It looks like and actually is a valve cover (covers the springs, keepers and stems) but on the other (internal ) side is the valve. There's a rubber hose that goes to the air horn so you might want to check to see if the hose is connected but the valve would work without it (sans air pollution). More than likely, your oil control ring is either worn out or cracked, which is not uncommon. 700 hrs is moderate for this type of engine. How large is the area that you cut? Are there many hills? Are there many trees? Do you bag or discharge? and finally, what kind of maintainance do you perform on a yearly basis. I've got to leave my consol for a few hrs so please respond to what I've asked and as soon as I return, I'll tell you what I think might be the situation and how to approach it. OK, seeya later, Sincerely, Dave
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Customer: replied 8 years ago.
I have never mowed a large area, about 8000 feet max. There is a hill in the back but it wouldn't qualify for many. I have always bagged. I do an oil change and filter clean yearly. Thank you for your input.
Expert:  The Small Engine Doctor replied 8 years ago.
Speak to you in the morning
Expert:  The Small Engine Doctor replied 8 years ago.
Hi Mr "T". You know, when I think of it, I once had an old (believe it or not) HOMELITE, rear engine rider that someone gave me because of oil consumption. It cut grass and provided mosquito controll at the same time!! I did the same thing that you are doing, keeping it below the full line and used it for two more cutting seasons. Of couse, being in the business, I always had a wrench and plugs around so it was no big deal for me, but someone else?, I dont know. I'm afraid your going to have to deal with it until it quites or replace the engine. Let me know what you are inclined what to do and I'll see if I can help you get thru it with as less "pain" as possible, and thanks for the fee, Dave
Customer: replied 8 years ago.
I went through it today and finally found the crankcase valve. It is actually right behind the carb. In fact I had to remove the carb to get to it. It seemed fine, I am sure it is a broken ring like you said. I changed the oil and fixed the oil leak on the valve cover. I cleaned it all up and it looks great, but as soon as I fired it up and out it under load the same thing as before. I just did the bug control thing until it was about a pint low and it smoothed out.
You talked about replacing the engine, I just planned on putting in a set of rings, you think that is not the way to go?? I can see it if I get in there and find the cylinder wall scared or something.
Thanks for your help.
Expert:  The Small Engine Doctor replied 8 years ago.
Hi Les, The reason I spoke of a new engine is that most people (these days) just throw things out and wouldn't want to be bothered. Me personally, I wouldn't even think of new, unless like you said, it had a scored cylinder or a bad crank. The only thing that I would suggest though would be to put in a piston ASSY. That way, you get a piston, ring set, wrist pin and w/p clips. Replacing the rings alone would "buy" you only another year and sometimes they actually break because they dont have the support to keep square in the cylinder with an old piston. At any rate, when your ready, give me a shout and I'll walk you thru it. Thanks for the "accept" and if you get a chance, any feedback would be greatly appreciated, Sincerely, XXXXX XXXXX SED