Oil leaks on Briggs 21hp

[carpetcleaner]

I have about 5000hrs on my Boxxer 421. It just started leaking oil. It was leaking from the breather hose that connects the valve cover to the air filter housing, so I replaced it. I also replaced the valve cover gaskets and the "o" ring on the valve cover that splits for the breather. There is oil still leaking from the valve cover breather hose, right at the air cleaner housing. The new hose fits really tight and doesn't seem like it should be leaking.

There is a lot of oil leaking, way more than it seems should be coming from that breather hose. There is enough oil inside of the air cleaner housing to cause oil to leak out of it. Anyone know what I should check?

 

[renegade_cowboy]

I had the same issue, you need to adjust your valve clearance. It got so bad that it kept bending push rods.. so I just ended up buying a new 21 hp briggs online for $1255 with free shipping.

Google your problem and it will give you more details with your problem.

5000 hours is a lot of hours, expect to replace or do massive overhaul sooner than later.

 

[Duane Oxley]

If it's an air- cooled Briggs, there is a breather filter under the air filter that gets clogged and causes the problem you're describing. When you remove the filter, remove the plate that it rests on and you'll see a rubber hose with a couple of angle turns molded into it. That hose runs from the plate (where it points to the carb intake) to the filter. It connects vertically to the filter, which is housed in metal and looks sort of rectangular, with one side shorter than it's opposite side.

There is one small bolt that bolts the filter down. Remove the bolt and lift (you may have to pry it a little, but no need for concern...) the filter off of the engine. Spray the filter full of carb cleaner a few times and blow it out with compressed air, then reinstall it. The seal under it should be okay, but it wouldn't hurt to put a very small amount of hi temp (copper colored) silicone on it to be sure to get a good seal.

If the filter is the problem, that will fix it.

 

[XCC]

Also check the oil drain. My Legend had developed a crack in the drain hose and my PowerClean had five pieces of brass to go 4" with a 90 deg on the end. The brass probably cracked from vibration. The only other high risk areas for leaks will be the crank seals.

 

[carpetcleaner]

Thanks for the help. My machine doesn't have that filter under/in the air filter. I bring it to my distributor for them to have a look at it. It seems to be getting worse by the day.

 

[Jay D]

500hrs work on it, 5,000hrs REPLACE IT. thats alot of hours for a aircooled engine, you got your moneys worth. you can start throwing time and money at something that should be replaced so you can make money cleaning carpet. I am cheap but there is always a point of needing to stop being thrifty when it comes to your livelihood.

 

[carpetcleaner]

I talked to my distributor today. I thought that they were going to try and sell an engine or at least a rebuild. I was told 5000 hrs is "just broken in" . I good guess would be valve seals. I going to put the seals in this weekend and inspect the cylinder walls. There are quite a few companies around here running 421s with over 7000hrs and still all major components are original.

 

[hogjowl]

You've gone 2500 hours past the normal Brigg's replacement time.

 

[Deltaflooring]

The brass mostly cracked from vibration and also check the oil drain.
sacramento tile

 

[Charlie Lyman]

I had to replace my motor at 3600 hrs. You got your money's worth. The heads could be warped, or many of the other issues listed above.

 

[carpetcleaner]

Valve seals didn't fix the leak. There is less leaking, but it is still a big leak. I guess it is time to rebuild or replace.

 

[renegade_cowboy]

Valve seals didn't fix the leak. There is less leaking, but it is still a big leak. I guess it is time to rebuild or replace.

You have a couple of options for buying a new engine. You can buy locally, but it was about $650 more than buying online. I bought a 21 hp briggs online and got free shipping on it as well.. I paid $1255 for the engine that came with a 3 year warranty and got here in less than a week.. didn't even have to pay tax on it.

http://www.smallenginewarehouse.com/pro ... gine&HP=21

 

[steve g]

I haven't seen very many air cooled engines run 5000 hours man that is a ton of hours. your lucky pick up another engine and put it in. look at it like this when the engine does go bad you will be out of work for several days this will cost you as much money you would save by dinking with it. I have always has great luck with briggs engines I never understood why the industry considers kohler an upgrade as those are the engines I have had more issues with and have needed to replace earlier than I thought I should have.

I have an 18 hp briggs that burns no excess oil, the oil is also clean even when it needs changing. oil and filer changes every 50 hours sure has helped. engine has 2500 hours on it. I see no reason it can't go alot more. but I am thinking about replacing it with a 21 or 23 hp engine as I think they are the same externally, then overdriving my blower with a smaller pulley 10% this should load my blower more and make my machine produce more heat and vacuum. its on a prochem legend.

 

[devocean]

I will never buy Briggs anymore. You are lucky if you get 1500 hours out of these engines any more.I started replacing all of my units with Kohlers.I have been in the business for 25 years now.I remember when i could get at least 4000-5000 hours out of a Briggs,not any more.Briggs never should have started making their engines over seas.Briggs used to be a quality machine,too bad.I have an 18hp briggs that that had 300 hours on it,started leaking oil around both heads.Took it back to distributor and was told the heads were warped during construction.Had another one 1 year ago that we had to replace with only 1100 hours on it.Replaced with a kohler.Kohler also runs cooler,quieter,and burns less fuel.Also,Briggs WILL NOT stand behind their warranties.

 

[Ron Werner]

I am replacing my Kohler, crack in the block. Its got a hairline at the top at the back, behind the carb. Couldn't see it till it warmed up. only 1900hrs on it.
Originally thought it was just the oil seal at the front, but discovered the leak after that was fixed.
Now I'll have lots of parts and a 3yr warrantee

 

[Dougb1972]

BOXXER 421

You have a couple of options for buying a new engine. You can buy locally, but it was about $650 more than buying online. I bought a 21 hp briggs online and got free shipping on it as well.. I paid $1255 for the engine that came with a 3 year warranty and got here in less than a week.. didn't even have to pay tax on it.

http://www.smallenginewarehouse.com/pro ... gine&HP=21

Do you have the model number of the one you bought so i order the right one?

Thank you
Doug

 

[renegade_cowboy]

Do you have the model number of the one you bought so i order the right one?

Thank you
Doug

I don't have a boxxer, so not sure if the shaft size is going to be the same.