[AT] 420 - the rest of the story

Cecil Bearden crbearden at copper.net
Sat Sep 6 16:59:25 PDT 2008


Paul:
What type of gasoline are you running.   Regular Unleaded or premium 
unleaded.  I have had many small ONAN engines that run fire pumps.  The 
pumps need to pass a test of 125 PSI pumping 25 gpm.  I can only get 95 
psi from regular unleaded and a very rich carburetor.  With premium 
unleaded I get 130 psi and do not have to richen the carb setting.

I also would think that the float level was low, or you had some kind of 
restriction between the needle and seat and the fuel tank.

  Just my $0.02

Cecil in OKla

Paul Waugh wrote:
> Some of you may know, my 420 quit while bush hogging some low ground of my sons.  I drug it back up to the top of the hill under a shade tree and did some of my things with the carb (it would start and barely run). No luck, not being a carb person that did not surprise me.  I sent it off to Bob Dillner in PA.  The man knows his stuff, and is very easy to communicate with about your problem.  He rebuilt it and put it on a test engine, all was well.  I put it on and I had the same problem!!  Now I have never met Bob Dillner, but I talked to him, and I knew it was NOT the carb.  Bob sent a list of things that are often wrong with a tractor not running. Spark was at the top of the list, so I checked. Now, I am 1/2 blind, but it looked like they were only about 1/2 of a matchbook cover in gap. I opened them up and bang she took off, rough but running.  I tinkered with gap and very small carb adjustments, better but not right.  And even though it had 1/3 tank of gas it would not
 g!
>  o forward up the 'hill' (about 40 degree angle), it would back up but not forward.  
> 
> I took off the gas tank, and for being 52 years old, it was pretty darn clean. I Kwik Poly it and back on, no change.  So I decided the change plugs, points, condenser and rotor.  Today, after putting it back together, no spark at all. I get out my test meter and start checking.  While doing that, a 'crimp on' end came off a wire in my hand.  Fixed that and had spark. Not only that but it ran with out any pauses, roughness of any kind. I put another 3 gal of gas in and was able to drive it up a pretty good slope.
> 
> The only thing is, I still have to run 1/2 choke compared to 3/4 choke before. I have sprayed carb cleaner all over the intake, carb, and areas connected to it, nothing changes. I can live with a 1/2 choke, as smooth as it is running.
> 
> And that is the rest of the story. Thanks Bob Dillner.
> 
> Paul Waugh - IN
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