Stihl 4-Mix - FS110 Carboned Up?

[HarleyT]

Oddly, this hasn't devolved into an oil/additive thread...

MMO rules!!!!!

 

[SteveSr]

Anybody have a recommended valve adjustment interval for these machines? The Service Manual says nothing. The Owners Manual says "as required"... DOH! Anyone have a realistic interval number?

There is also a note in the owner's manual to have the valves adjusted by a dealer at the 139 hour mark with the implied "as required" thereafter.

 

[Lee192233]

I would guess I had about 40 to 50 hours on mine and the valves needed adjustment. The dealer told me every 2 years. I wish they had hour meters built in.

 

[SteveSr]

I would guess I had about 40 to 50 hours on mine and the valves needed adjustment. The dealer told me every 2 years. I wish they had hour meters built in.

The new "xx1" series have the m-tronic data logging in them. Trouble is that you need the MDG interface, computer, software to access the numbers.

 

[Chevboy0167]

A friend at work has a Stihl 4 choke trimmer. Might be same model, I don't recall. 3 weeks old/used and needed dealer trip for valve adjustment.

 

[CentaurG2]

I was an early adopter of the 4-Mix. I think I have one of the first FS-130 made. This was before Stihl introduced Ultra synthetic 2 stroke mix. I have beat the snot out of that trimmer. It will start first pull every time. I have never adjusted the valves.

 

[Lee192233]

I was an early adopter of the 4-Mix. I think I have one of the first FS-130 made. This was before Stihl introduced Ultra synthetic 2 stroke mix. I have beat the snot out of that trimmer. It will start first pull every time. I have never adjusted the valves.

Love my KM110R! I till with it, leaf blow, run a pole pruner, weed eat, cut brush, trim hedges and run a bed redefiner.

 

[Canyon Angler]

I know someone that said the water worked in a 5.7 vortec. I’ve never tried it.

I've poured SeaFoam down the intake manifold of my marine GM 350 (Vortec) while it was running...makes a mountain of smoke but supposedly helps decarbon it...

 

[HarleyT]

I've poured SeaFoam down the intake manifold of my marine GM 350 (Vortec) while it was running

That's what I am talking about!! I am a WD40 man myself!!!

 

[HarleyT]

When I was 14, all I needed was a can of WD40. and one of my sister's Glamour magazines, and I was a happy camper!!

 

[Chevboy0167]

Maybe something in the BG line of products to de-carbonize???

https://www.bgprod.com/catalog/engine/

 

[Chevboy0167]

Yikes!... Pricey

https://www.ebay.com/itm/362620107542?epid=1722143297&hash=item546dd7bb16:g:~XQAAOSwpMZcsXZ0

 

[67L36Driver]

I know someone that said the water worked in a 5.7 vortec. I’ve never tried it.

Mid 70’s, it was a bimonthly requirement to prevent pinging and run on.

16 oz of water from a pop bottle down each carb throat at a 1500 ish idle speed.

Don’t park anything important behind the car as it will be covered in wet exhaust crap.

 

[SteveSr]

Picked the weedeater up on Thursday from an associate. Line is .105" square and difficult to cut even with a pair of side cutters. Anybody see anything wrong in these photos?

 

[HarleyT]

Picked the weedeater up on Thursday from an associate. Line is .105" square and difficult to cut even with a pair of side cutters. Anybody see anything wrong in these photos?

View attachment 919047View attachment 919048

No cutter.

 

[SteveSr]

No cutter.

Correct. What does Stihl say about using 0.140" edge-edge line? powerhead overload? Now wondering if this was the root cause or just a contributing factor.

 

[HarleyT]

Could be a factor. Personally I run my trimmers with no shield, so I can get my heavy line a large swath, but officially the line is to keep the shields intact, etc., or the warranty is void.

 

[Jason Pitcher]

I was an early adopter of the 4-Mix. I think I have one of the first FS-130 made. This was before Stihl introduced Ultra synthetic 2 stroke mix. I have beat the snot out of that trimmer. It will start first pull every time. I have never adjusted the valves.

I was an early adopter of the 4-Mix. I think I have one of the first FS-130 made. This was before Stihl introduced Ultra synthetic 2 stroke mix. I have beat the snot out of that trimmer. It will start first pull every time. I have never adjusted the valves.

Same here. Just new plugs and fuel filter.

 

[SteveSr]

I finally got some cooler weather and mostly time to tear into this engine. The main issue found was that the exhaust valve was crusted with hard carbon and leaking like a sieve. The exhaust passages behind the valve and to the muffler were also caked in fairly soft carbon. The inside of the engine was also covered in plenty of mix oil. I suspect that this accumulated due to poor running after the exhaust valve started to leak. The inside of the engine and valve train was covered in soft black carbon and oil that will wash away with fuel mix. Other than this the engine looks almost brand new inside.

Unfortunately, the root cause is still unknown. At this point I am speculating that the engine and cam gear got hot and caused the decomp cam to get stuck and allow carbon from the poor combustion to get hammered into the valve seat. Anyone else have any better ideas?

 

[LoneOak]

Rev limited coils do fail, have you replaced the coil yet?