Date: Sun, 22 Dec 1996 20:49:17 -0800
From: Mike West <mwest@cdsnet.net>
Subject: Air Leaks n' stuff

I was out surfing on the net, looking for some data on carb jet sizes
and found myself reading some trouble shooting guides on small
engines.

 As in water sports and the like. 8500 rpm, I think.

The thing about such engines, is they suffer the same problems as we
do only because of their size or rpm, it's more acute.

This one in particular was on air leaks.

An air leak to them means lean burning and possible piston seize
at hi rpm. Runs and acts fine at low rpm.

So they have to do pressure tests on the whole case. 6-9 psi.

Alright we don't have such an acute symptom. Then again, we have
problems the V8 boys don't.

It's all kind of relative to your size.

Still, let's look a little deeper into some of our own type problems.

We know that any leak of air can affect the air fuel mixture.

Found that out in the smog test stuff.

Not just the intake and exhaust manifold.

That means the leaking valve or stem, or rings, or even a push-rod
tube leak, can mean an air leak to the fuel mix.

There's also the loose heads that haven't been properly torqued.

Where I'm going with this is that a guy buys a '69 and it backfires
a lot. Oil dripping from every pore.

He seals the intake and exhaust and sets the timing and fiddles with
the carb and it still does it. He's dissed.

There are at least a dozen things that can cause the engine to back
fire and he's maybe fixed two.

There is no help for this guy till he completely goes thru the engine
and makes it all right.

Those same problems will make an engine overheat.

Richening the carb will not help.

Thickening the oil might for a time but that engine is on it's way
out. Poor thing, mean ol' owner.

 west