Leak down test

Thanks very much, very helpful

Cobba if you are near Brisbane you can have my aircraft leak tester to use. All aircraft engines get a leak-down test every 100 hours.

As someone says just put it in gear - in aircraft they have to get someone to hold the prop.

Listen in the oil filler - hissing means ring leak.

Listen in the exhaust - hissing means valve leak.

Bubbles in radiator - head gasket or crack.

They all will leak down within a minute or so as nothing is perfectly sealed so the held compression is the true test of condition.

She talks like a threshing machine but all good stuff.

  www.youtube.com/shorts/Lxkzxz8vnWk


Here is a simple kit made up
 

Why stuff around? Here is a proper aircraft style leak tester for $35 free postage from a South Australian seller.

 

Thank you Lang for your kind offer but I'm a little bit further south near Taree . 
I will make an adaptor to fit the 18mm plug hole n use my vacuum pump to check k it out. 
In the mean time I've been busy making a mower look pretty again. It the bright yellow Villiers Torquemaster that got covered in dust. Have to wash it up to take to the rally on Saturday. Been busy with another special project for Dee n I to admire. It will be hung on the lounge room wall once complete. I borrowed an idea I saw while on our last travels when in Inverell viewing a rather large mower collection.
More to come soon.

I have the second tester Lang posted.

Works well and simple enough that I can use it.

Well today I had a look at David. Found some surprises right from the start. The screw on cap on a spark plug had unwound some how n stripped the thread n was stuck inside the ht lead. Removed all plugs cleaned n gapped them. Cold compression test came in at 75 psi on 3 pots n 74 on another. For a TVO engine this is good. Previous test shows 2 pots were at 70 psi in the past so they are now pretty close. All ht lead past continuity easily. Then another shocker, the points. The gap was tight but the contacts were filthy. Maybe tight because of the dirty surfaces. Took them out n touched them up with my nice new diamond points file, it doesn't mess about getting them clean. Then dressed them smooth on an oil stone. Fitted them back to 0.012" as per spec. Checked all leads were throwing a nice spark then fitted the plugs n fired him up. Sounds good again but I think a road test is in order to double check. 



youtube.com/@cobbadog2070?si=tFHizChY3PLLohoX

Did a quick road test stopping at times for a mixture adjustment n a photo shoot. Still had a bit of a flat spot under load but decided to head home n do more adjustments. Now sounding a bit better I did another short 2k run around the block. Got part of the way n stopped for a bit more finer tuning. Did this a couple of times then he just stopped. Found that now both fuel tanks were blocking up. I've carried a plastic tube to blow back up the fuel lines n that works for a while but now only for about 600 mtrs. PLUS now the rocker cover has decided to leak oil out in bulk, why not? So ive parked him up n drained both fuel tanks n looks lije cutting the arse out of the tanks is the only way forward.

I just had this situation with the rider mower. Drained the tank fully, let it dry then blew it out with compressed air. I was surprised how much crap came flying out. Seems fixed now.

Jarrod. 

The gap was tight but the contacts were filthy. Maybe tight because of the dirty surfaces.

Cobba, if the capacitor or condenser is faulty, it will cause the points to burn very quickly. 

Also, it the rubbing block is dry, it will wear down quickly. Thus closing the points but also changing the dwell angle and ignition timing.

Then once you blow it out get a bit of hose and fit it into Dee’s vacuum cleaner and suck up anything you can get the hose to
You might have to suck up to Dee get the vacuum cleaner but I’m sure she’ll know it’s for a good cause

Bluey