YS 140DZ fault?

[chadnortheast at shaw.ca]

I had an issue with my pump last year.  The problem started after about 5 gallons of fuel through the engine.  

What happened was the pushrod coming out of the top of the pump started to oval the pump housing (aluminum).  This allowed fuel to leak past the pushrod and get into the valve cover causing an incurable rich condition.  The motor would not throttle up, would quit during snaps, was impossible to start etc etc.

A new pump solved the problem, and I have not had an issue since replacing it (some 300 flights later).

Apparently they fixed this by increasing the contact area between the pushrod and pump housing.

Its easy to see if you have this problem, remove the valve cover and remove the tappet so you can clearly see the pushrod and housing.  If the pushrod has any play in that housing you should get a new one.

>From what Dave told me, there were only a few of us who experienced this and it was a pretty simple fix.

----- Original Message -----
From: Dave Smith <dfs at navnet.net>
Date: Tuesday, April 22, 2003 10:07 am
Subject: Re: YS 140DZ fault?

> MessagePeter:  A friend had similar problems yesterday.  See my 
> query to Dave Shadel at RC Universe,under the YS Engines section.  
> Maybe his answer will address your problem?
> 
> Dave
>  ----- Original Message ----- 
>  From: Peter Pennisi 
>  To: discussion at nsrca.org 
>  Sent: Tuesday, April 22, 2003 10:58 AM
>  Subject: YS 140DZ fault?
> 
> 
>  Hi All,
> 
>  I tried running my YS140 DZ for the first time on the bench (I 
> am glad that I did now) without much success.
> 
>  Main needle was set to 2 turns initially and regulator untouched 
> from factory setting. Rest is usual with 16 x 12 APC.
> 
>  Engine started OK and idled briefly however when I started to 
> open up the throttle slowly it would start to run hard lean from 
> half throttle and then stop abruptly (detonated). Then I opened 
> the needle another 1/2 a turn and same result. I then wound the 
> main needle in to 1 1/2 turns and same result. During this period 
> I started to hear a rattle noise from around the mechanical pump 
> assembly so I stopped my testing.
> 
> 
>  I spoke to the Australian agent and he mentioned that some 
> engines were getting around with some suspect pumps. He has 
> offered to supply a spare pump or otherwise send the motor to him 
> and have it repaired. (Yes, not replaced)
> 
>  My question to everybody is how many people have had a pump 
> related problem? and secondly is there any truth that the pump may 
> require some lapping in as he believes the tolerances are probably 
> a little tight.
> 
>    
>  Regards,
> 
>  Peter
> 
> 

=====================================
# To be removed from this list, send a message to 
# discussion-request at nsrca.org
# and put leave discussion on the first line of the body.
#