it's impossible

[Terry Martin]

swagaero wrote:
> 
> Terry Martin wrote:
> >
> > Terry Martin wrote:
> > >
> > > Tuck wrote:
> > > >
> > > > I'm tired of screwing around with the car trying to make it run right, let
> > > > me solicit your opinions.
> > > >
> > > > I have hesitation at random rpm spots when the engine is under heavy load....
> > >
> > > Check your dewpoint at the time of hesitation. It sounds a lot like carb
> > > icing, (I know, it's not carbed), ...yada yada yada
> >
> > I neglected the obvious, don't check anything, just port a heat riser
> > onto the intake and see if the problem goes away. BTW, me and carb icing
> > don't like each other. 
> 
> Carb heat neat thing with a carb usless with MPFI Flying is more fun
> then walking
> 
> Steve

OOOh I beggeth to differ. I can see by your signature file, (& the fact
you still liveth), that you probably know a more than a little about
wing icing. There is no difference between accelerated air flow in
manifold or over a wing. It is the same basic venturi principle. In a
manifold relative air pressure drops, dropping the temperature
accordingly. Pressure drop plus temp. drop equals water drop. ;-) (Ain't
I clever) Anyhow you can and do get condensation, if not actual icing
inside any manifold, if the conditions are right. The condition of full
throttle is probably the most relevant. RPM matters, but hesitation at
random RPM probably has less to do with RPM than any other factor.
Anyhow if you suck water droplets into a marginal spark it probably gets
worse than marginal. 

I'm not suggesting carb heat as a fix, just a diagnostic. It's about the
cheapest and easiest thing I can think of, particularly if the problem
goes away. A properly running engine will eat any induced condensation
for breakfast stone cold.

One other simple thing, rotate your spark plugs 1/4 turn if you can
without buggering anything. 

Terry