OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines B&S using oil

hi, i have a rover ranger thats using oil. i am thinking of new rings but i need a manual to help me through the exercise. any ideas where i would find 1.My mower has an 11 h.p. engine or would it be best to source a new motor.i have already rebuilt all the hanging system for the deck.

First question is, are you sure it isn't leaking the oil? You can make a fairly reliable test for whether the rings are still sealing properly by doing a compression test, then squirting a spoonful of engine oil in through the spark plug hole, reinstalling the spark plug, and repeating the compression test. See if the compression is noticeably better with the oil in there. (Just the amount of resistance felt on the recoil starter will be sufficient to show what is happening.)

If sealing the rings with oil improves the compression substantially, your rings are not sealing adequately, and need to be replaced. Depending on what has happened to your engine along the way, and how many hours it has run, replacing the rings is likely to be well worth while. Replacing the whole engine is something you do if there has been a serious mishap (like a broken connecting rod, a seizure, or a severe dusting due to the air filter leaking or being missing).

If you read the long series of numbers stamped on the cooling air cowl of your engine, you can find the model number (this is the first of the three blocks of numbers on the cowl). The model number allows you to find your model in the B&S engine overhaul manual, which is here:
http://www.tpub.com/content/recoveryvehicles/TM-5-4240-501-14P/css/TM-5-4240-501-14P_70.htm

Use the "next" button on the top of the page to view subsequent pages - there are 225 in total.

If you have questions we'll be happy to try to answer them. Post the full long string of numbers from the cowl (all three blocks, not just the model number) and some pictures of the relevant parts of your engine when you do so. That gives us enough information to know precisely which engine you have and when it was made, so this thread will be useful to other members in our archives.

If its not loosing copius amounts of oil or blowing clouds of smoke you could always just keep topping it up.

Some oil use is to be expected with an engine of that design and age.

Another question: what kind of oil are you using? The older B&S engines (essentially, just about all of the side valve ones) require SAE 30 oil, not multigrade. B&S make that clear in the owner manual and the overhaul manual. If you use multigrade - especially SAE 10W30 - those engines will use quite a bit of it. Their oil control rings were not designed for the very light oils that are used these days to reduce fuel consumption. However if it is blowing blue smoke, even with multigrade oil, you have a problem.

I suggest that if the compression is OK (i.e. same with and without oil in the cylinder), you try using SAE30 oil and see how much is being consumed. Normally heavy consumption of the correct oil only happens if there is heavy blow-by (detectable with the compression test) or if there is leakage somewhere.

Hi again. thanks for the input i havent taken any photos yet but i have the required numbers: Model 253707 Type 0185-01 Code 85050810
I am using SAE 30 oil and it blows a light amount of smoke.
I used 2 tanks of fuel and the oil on the dipstick went from the high mark to the low mark.The engine has no oil leaks.
Even though it uses oil it has plenty of power.Next job will be compression test.

Regards Frank

Frank, I'll tell you what the numbers mean in case you don't know already. The model 253707 is a 25 cubic inch (410 cc) fourth generation engine design with a vertical crankshaft and a Flo-Jet carburetor. It has plain main bearings and a 12 Volt gear drive electric starter with alternator. Here is the Operator's Manual:
http://bsintek.basco.com/BriggsDocumentDisplay/msoBGL-K_ny7tH217FzoPu.pdf
Here is the illustrated parts list:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6nlyHVJ1DajI.pdf

Your engine was manufactured on 8 May 1985.

Given that it is blowing smoke it is highly likely that it needs new rings, but the compression test should confirm the condition of the rings one way or another. Before deciding whether to replace the rings, turn the engine over slowly by hand (spark plug lead disconnected, of course) and listen for any bottom-end clunks or inexplicable sounds other than the usual Briggs ones. Unless it has been run dry of oil at some time or run with the governor out of action, or it has been "dusted" (run without the air filter working properly) chances are it will just need new rings, valves lapped, crankcase ventilation valve cleaned, fuel tank cleaned, fuel line and carburetor cleaned, and a standard tune-up as per the Operator's Manual. That counts as rather simple maintenance. However take a look at the bore carefully. Unless the engine has "I/C" in large letters on its air cowl, it is likely to have an aluminium bore, which can wear out much sooner than the cast iron bore of the I/C engines. If the bore shows significant vertical stripes that have some depth, it will have to be bored and have an oversized piston fitted, which is relatively costly. A damaged bore will not seal properly even with new rings.

Hi Frank.

If it was me, with no leaks and blowing smoke, I'd forsake all the testing and go straight to fitting a new set of rings, provided the bore is ok. I'd hazard a guess in saying that a light amount of smoke would suggest that the bore is in fact ok, and would need only a light hone only to remove most of the polished finish. More or less just scratch the surface. Be careful not to remove all the polished finish as this will make the bore oversize, (you can tell by measuring the ring end gap).

Thanks for all your input, the information has been helpful
Regards to all. Frank

Given the rest of the info, i would be pulling the head off for a look at the bore, if there is no obvious damage i would look at new rings, if the bore did look a bit suspect i would just learn to live with it and try and get as much life from the engine as possible.


And while the head was off i would take care of the valve clearances.
I think one good thing to check when doing that is the slop in the valve guides. They can get pretty bad, especially the exhaust, mostly the bigger motors have a steel (or non aluminium) guide in at least the exhaust, i have seen a few 3 and 3.5Hp motors that have had failry big slop in the guides, not an easy thing to rectify propperly, definatly something that will cause oil usage. But it does not seem to stop them performing adequately power wise.

To get the collet type valves out of the Briggs motors i just use an over the cylinder head type valve spring compressor. Its a bit tight in the hole but it works.