OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk Briggs & Stratton OHV intek 60

I don't know how reliable that fan repair will be, but time will tell. It will be interesting to hear how the engine performs.

Hello, I have started this engine and it isn't running right.
I took a video of it, but it is 40Mb.

Exhaust is emitting not blue or black smoke but white puffs of smoke.
Spitting through the carby at times.
Vibrating due to running out of balance.

After assessing it, changing valve clearances, I have pulled it down again and removed the decompressor completely.
I have it all back together and sealed up again.
I wiil try it again today.
There is quite a bit of compression when starting it now, but not unreasonable.
Like starting a Victa power torque with the decompressor blocked off with a spark plug.



If the engine runs well, I will order a new camshaft and fan.
Some spark plug specs for this engine: Champion RC12YC, BS part no. 499608, clearance .020

I have had this engine running this morning, symptoms are the same, so the decompressor was fine after all.
I am going to clean the carburettor again, which I thought was pretty good.

I cleaned it as per this link below:
http://outdoorpowerinfo.com/repairs/briggs_carb_790120.asp

Cheers

It sounds as if the mixture could be unstable, due to an intermittent air leak or carburetor fault, or a leaking valve or head gasket. You'll need to go through all that again.

If you worked on these engines regularly, it would be useful to keep a "comparison carburetor" that was known to be good.

Thanks, I have rechecked all the clearances and after adjusting the armature air gap down to 0.008" it runs a lot better.
This clearance is a lot smaller than my usual visitors card.
So, bit of a lesson leant there to actually look in the manual for the correct clearance and check it with feeler gauge.
I also cleaned carb again and ensured all the inlet gaskets were sealed.
I have tried a few different spark plugs as well, to try and improve how it runs.

Engine is running ok, still has a intermittent pop from exhaust and a bit of white smoke from exhaust.
I haven't done any mowing with it yet. I will report back when I do.

I have a question about how engine oil finds its way under the rocker cover and does it actually lubricate the rockers. Its not flooded with oil. Question might sound strange.

Usually the oil just slops around between the sump and the rocker cover depending on the slope of the ground. There should be a drain through the lowest part of the head, with a matching hole in the head gasket, to ensure that no oil is trapped in the rocker cover. I've put a yellow oval around the drain hole in your model's head gasket (P/N 697230):


If you put the head gasket on upside down, you'll make a real mess of the drainage system.

The pops in the muffler suggest that the exhaust valve is leaking, or the spark plug is faulty, or either the valve timing or ignition timing is wrong. Coupled with the fact that it is slowly improving, and it had apparently been unused for quite a while before you got it, my first bet would be leaking valves. This is usually due either to them not seating properly, or (perhaps more likely) sticking in the guide just before they close. It is a problem that needs to be fixed.

Also, with regard to your issues with the coil-to-flywheel gap, I suspect you were following a red herring. Refer to this Briggs FAQ:
http://www.briggsandstratton.com/us/en/support/faqs/ignition-system-theory-and-testing

In particular, consider this part of the answer:

"An armature air gap that is too wide will prevent spark. Not true. Well, sort of not true. Briggs & Stratton air gaps cannot be made too wide to prevent spark providing the coil is healthy and the engine is spun over fast enough. A wide air gap, say .030" will ever so slightly retard the ignition timing as the magnetic field takes longer to build within the coil windings."

Thanks Grumpy,
I will revisit the valves, yes, I think maybe valve is sticking in the guide.
Not much to mow here, so I will give it a good run at some point.

I've got the idea now, with how oil enters the rocker area.
This head doesn't have that hole, the holes are for locator pins, so it must come down the push rod tunnel and then the hole in the bottom of the plate pictured. Which I didn't notice until your explanation.

If it doesn't leak, or collect sludge in the head or rocker cover, I guess it works well enough without the drain hole then. I'd like to say that Briggs wouldn't have deleted the drain unless it wasn't needed, but I no longer have that much confidence in Briggs' design team, following some of their Intek exploits.

Hello,

I ran this engine again, it ran great until it warmed up. the symptoms then were:
#missing at times.
#occasional spat through the carb; and
#white/light grey smoke at times from exhaust that seemed to come in waves.

After pulling it down, the intake valve stem still had residue on it, so cleaned it off with an oily scourer pad.
I am confident the valve seats are good.
Reassembled them with assembly grease on the valve stems.
I'll start it up today and fingers crossed it will be ok.
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While it was apart I investigated how the oil gets in and drains from the rocker cover area.


You can actually see the decompressor through the oil entry hole, so you could inspect for a broken spring through this hole without removing the bottom plate.

Also, a theory, does the decompressor have a secondary role of throwing oil into this hole, once it flattens out at speed?
Still a bit unsure of how all of the components under the rockers get oiled.

I cant see inside the engine when its running, but imagine the oil flicker with the addition of the pressure changes inside, creates an oil mist and this area under the rockers is oiled by a mist of oil?

There seem to be a number of things that might cause those symptoms, Mark. My first guess would be that the decompressor was stuck in the part-compression mode. My second would be erratic ignition.

A splash-lubricated engine has both oil and oil mist flying around all over the internal spaces, and when it has a vertical crankshaft, this can easily be made to extend to the rockers because of the splashing and surging of liquid oil, as well as mist, through any passage that exists.

Here is the valve compartment of a Honda GXV140 cylinder head. The oil feed and drain holes are circled in red:



Note that the same passages are very much larger where they pass through the crankcase: they are reduced to those small sizes just where they enter the valve compartment. Note also that the feed hole (the upper one) is somewhat larger than the surge/oil return passage (the lower one). This has the look of having been developed by trial and error, to get the desired amount of oil in that compartment.

On your small Intek, Honda's high and low oil passages must be replaced by something else that works. I don't know how much oil the little tin decompressor would fling through the hole directly beside it (on a vertical crankshaft engine), and I have no real confidence that tiny drain at the bottom of the pushrod compartment would remain un-clogged over the long haul, but your guess as to how it works sounds plausible right now. I haven't seen one of those engines so I can't look for alternative explanations. Overall, I suppose the proof of the pudding is in the eating: either the valve gear gets oiled, or it eventually shows signs of lack of lubrication.