OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Manual for B&S Intek 65

Does any one have a manual for a B&S Intek 65 Single Cyl OHV engine Model No 125602.The engine was on a 2006 Rover Pro Cut 560. It is blowing smoke but I don't know if I need to rebuild it or replace the breather valve.

There is a manual for the single cylinder Vanguard engines in the manuals section. The Vanguard was the original Japanese design which Briggs "redesigned" to make cheaper, to produce the Intek. Hence quite a lot of useful information can be obtained.

The manual concentrates on air leakage tests to diagnose combustion chamber leaks such as problems with rings, valves, or gasket. It relies on a combination of measuring air leakage rate to find whether there is a problem, and listening to where it is leaking from to identify the specfic problem. In a case like yours it may be sufficient to do a standard compression test, then repeat with a spoonful of oil in the cylinder. If the compression pressure increases substantially with the oil in the cylinder, the compression rings are leaking. On traditional Briggs engines this is quite a reliable indicator of whether the oil ring is leaking. However it will not work on Honda engines for example, since they have chrome-plated top compression rings which last a very, very long time. I have had a perfect-to-the-manual compression test result on a Honda GXV120 engine with the oil ring so worn it had a 3.6mm ring gap, and scarcely any oil control features left on the outside of the ring:


Here is what the oil ring was supposed to look like:


The engine smoked so much that its exhaust was white and non-transparent, gassing the whole street. In 5 minutes from a cold start it oiled a clean spark plug and stopped running. Meanwhile the oil level in the sump dropped by 3mm.

So, if a compression test with oil tells you the compression rings are leaking, you can expect the oil ring to be in bad shape. If it tells you the compression rings are not leaking, you will need to research whether your engine has a chromed top ring before you feel any confidence in the condition of the oil ring. Be particularly suspicious if the engine has had its rings replaced: amateurs are very prone to misassembling steel rail oil rings, with disastrous results for oil consumption.

To establish whether you have a breather problem, just look at the breather hose and the air cleaner where the hose enters it. If there is no oil in the hose, the breather is not injecting oil into the intake.