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Re: more tuning problems

To: Matt Gaetke <mgaetke@MIT.EDU>
Subject: Re: more tuning problems
From: Paul Hunt <paul.hunt1@virgin.net>
Date: Tue, 22 Sep 1998 20:12:18 +0000
Matt Gaetke wrote:
> 
>         First off, when I adjust the distributer to the point where the
> timing marks align properly, the engine all but dies (actually it usually
> gives up on me).  It runs best when the timing is well advanced (that's
> anti-clockwise, right?  say, 25 deg BTDC instead of 12 deg BTDC) of that
> point.  The other problem is that I can't run the engine at the 600 rpm
> recommended in Haynes (at least that's the rpm listed with the 12 degrees),
> see below.

The distributor runs anti-clockwise, so to turning it clockwise advances
the timing.  If the timing is over-advanced but idling at the correct
speed, then when you correct the timing the engine will likely stall,
just screw in the idle screws a little by little as you go.

>         I know the carbs are not balanced/not adjusted properly, and the
> engine sounds like it's running rich.  Further evidence of this is a
> considerable amount of dry, black carbon on the plugs (it doesn't look at
> all oily).  It also misses occasionally (timing?).  Of course there is a
> contradiction: the only way I seem to be able to keep the engine running at
> low (<1800 rpm) is with about 1/2" of choke.  I thought it could just be
> that the idle screws were out too far and it wasn't getting enough gas
> without the fast-idle cams ingaged, but with the choke in (even giving it
> more gas) it kills every time.  Nothing I've tried yet lets me run it below
> 1000 rpm.
>
>         I don't know how to call this one.  I've got a new condensor and new
> points on order.  The only part of the HT side that's not new is the coil.
> Maybe I just need to start over from scratch.  If so, how do I do this (step
> by step to the smallest minutia :) )?  How do I get the engine running at
> 600 rpm to adjust the timing with the carbs messed up?  I'd like to think
> I'm not in over my head, but I could really use some advice.  Anyone want to
> take an aspiring mechanic under their wing?  Thanks, guys.

Do the static adjustments on the valves, the ignition and the carbs
first (if you think the latter are way out) then the dynamic timing
adjustments then the dynamic carb adjustments.  It still sounds like
your idle screws are way out, the choke is just compensating for them,
maybe worsening the mixture along the way.  You should be able to
compensate for huge amounts of wrong mixture with the idle screws.

Cheers,
PaulH.



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