Re: [Fwd: Passed emissions]

[rhughes@domain.elided]

John, Harvesters,
>>If I'm not mistaken, the power valve on the model 2210C can not "blow
out"
>>per se.  It has no rubber diaphragm (as on other Holley models).  It's
>>possible it could leak... because it is a valve after all.  If it leaked,
>>this would effectively enrichen your mixture off idle.

You're right, there is no rubber.  It is a spring-loaded valve.  I use the
term "blow", because that's what people seem to usually say when referring
to power valves.  Whether it actually was faulty, I can't be sure, but the
spring in the old one seemed to have more play than the new one...  *And*
the change to a new valve did correspond (along with the jetting change) to
reduced CO.
>>Have you bothered to check other things on your engine... vacuum leaks,
the
>>EGR system, PCV system, etc.?  Small problems can add up cumulatively and
>>be difficult to track down.  Your carb changes might be covering up
>>something else.

My vacuum hoses are good, but it's possible my EGR or PCV went bad sometime
in the last several months.  Frankly, I never really considered these as
possible culprits, as my problem was a rich mixture.  A vacuum leak or
stuck EGR would *lean* the mixture, wouldn't it?
>When I get my AutoMeter vacuum gauge installed, I'll be able to watch for
>the power valve engagement, which should be interesting.
>>The vacuum gauge moves around a lot depending on so many
>>factors... mainly engine load and throttle position.

Bummer.  I thought it would be clear, given a certain vacuum reading and
"seat of the pants" feel, when the valve opened.  Also, aren't the valves
stamped with the in. of Hg at which they open?
>Anyway, this guy seemed pretty confident
>that something is wrong with the carb if I have to jet that small.  He may
>be right, as this is an old, tired carb.
>>Nope... I think they don't know what they're talking about!  That jet is
>>not far from stock.  I'll try and remember to look up the stock jetting
in
>>the IH shop manual tonight and e-mail you what I find.

I've got the shop manual, but I've never seen the jetting discussed.
Several times I've queried the digest as to what jets people run in the
2210C, and gotten no response.

>>The carb probably could stand to be completely disassembled, soaked
>>overnight in carb cleaner and carefully reassembled.  You'd be surprised
at
>>the accumulated varnish and crud this removes.

I did a complete rebuild last year (in order to pass emissions).  That's
why this year's problems were so frustrating.  My suspicion last year, and
what I still wonder about, is whether the air bleeds are clogged beyond
help...
>Holley makes jets down to about .40, but they are kind of hard to find.
>Lots of parts stores could order them for me, but no one had anything
>smaller than .50 in stock.  This lends credence to what the speed shop guy
>said, I think.
>>I don't see what that has to do with anything.

Well, just that I would expect the jetting to be somewhere towards the
middle of bell curve of sizes.  If I've got the smallest ones that are
readily available, that puts me in the lower tail of the distribution.
Obviously, that may indeed be the correct jetting, but if it is not
correct, there really is nowhere to go but up.
>You'll get *much* better information for your IH vehicle here on this list
>than just about anyplace else.

That's for sure.  But I don't always have time to wait for an answer, etc.

Thanks,

rob h