Stihl 084 starter kick back

[rwkbiker]

Still a work in progress. Received valve jet 1124-121-5403 as replacement for 1124-121-5400. The 5403 did not have the hole (top to bottom) through the valve like the 5400 had. Stihl is working with Tillotson to determine if 5403 will work.
Just in case I can’t revive this obsolete Tillotson carb, I started searching for options. It appears a Walbro WG-12-1, used on MS880, will work on 084. These are are available for about $100 new. I'll keep you posted.

 

[rwkbiker]

Just wandering - if Walbro wg12 does work as a replacement for Tillotson HT2A, why is that info not promoted?

 

[Robin Wood]

Does that carb fit in the right orientation or will that go upside down ?

 

[rwkbiker]

Hey Robin, upon seeing a WG-12-1 advertised for a Stihl 084, I contacted a Stihl HQ tech rep and asked about the fit - bolt up, linkage to master control and choke, fuel lines, access to adjustment screws, etc. He said all should fit. He noted the WG had a slightly larger jet that might skew the normal one turn out base setting, but should not impact tuning.

 

[Robin Wood]

Cool, let us know how it goes when you put it together

 

[rwkbiker]

Appears, no response from Tillotson to Stihl rep, but rep suggested trying replacement valve jet (5403) - without 1+mm hole. First, I disassembled original valve jet (5400?), attempt to restore function. Afterwards, vacuum/presure readings improved - somewhat similar to the new 5403. However, I reinstalled 5400 - saw performed poorly - similar to before. So, I installed new 5403 - appeares, performance at idle and mid-range rpm has been restored.

Unsure of impact of new valve jet, without the hole, on fuel mixture and performance at wot and top rpm - So, reluctant to run wot until I tune it with tachometer and 2ft or larger log. I'll let you know.

 

[rwkbiker]

I tuned and tested the 084 today, in 30+ inch poplar. Saw performed well - stronger than I remembered. Failing coil may have reduced engine power over time. Not sure of impact of new valve jet.
But, appears saw is back in business. Thanks for the input ... Wayne

 

[Robin Wood]

Good for you, if it cuts good who cares what problems it had

 

[rwkbiker]

Thanks for all the support - this was a great learning experience for me. Hope the shared information will help others.