Stihl Km85 kombi starting like a pig and cutting out - HELP

[wildflowerbill]

Hi all,

 

replaced fuel filter, fuel line, plug, cleaned filter. Fuel is fine and right mix obviously. Been acting up and cant seem to cure it. When it starts it runs fine for about 5 minutes and then cuts out as if short on fuel. It's a pig to restart.

 

Any ideas? It's driving me mad

 

cheers

[GardenKit]

You need to take tha carb apart, clean it an rebuild with new diaprsgms. Make sure you clean the internal gauze. While the carb is off replace the tank vent, dont mess about trying to clean it, just replace it.

 

Also, check and adjust the valve clearnces whilst you are doing the service.

[harrythecat178]

Ignition pack is prone to failure on those, could be weak spark. Borrow another and swap round

[C.J]

You need to take tha carb apart, clean it an rebuild with new diaprsgms. Make sure you clean the internal gauze. While the carb is off replace the tank vent, dont mess about trying to clean it, just replace it.

 

Also, check and adjust the valve clearnces whilst you are doing the service.

 

And I thaught barry knew it all

 

KM85 is not 4mix

[GardenKit]

woops! must learn to read the post fully

[spudulike]

You need to take tha carb apart, clean it an rebuild with new diaprsgms. Make sure you clean the internal gauze. While the carb is off replace the tank vent, dont mess about trying to clean it, just replace it.

 

Also, check and adjust the valve clearnces whilst you are doing the service.

 

I think the KM85 is two stroke - I guess the OP may spend all Christmas searching for the valves:blushing:

 

Back to the issue - try pulling off the top cover and muffler to make sure the piston is in good shape! If there are any deep vertical scores in the piston, it has been seized - you can also use a compression gauge if you have one - anything over 145psi is OK.

 

If this is OK, check the gauze filter like Barrie said, often worth pulling out the H and L screws and getting some carb cleaner down them plus check the metering arm height is correct - usually it should be level with the carb body when a flat edge is put across it!

 

If that doesn't do it, check the coil to flywheel gap with a business card - the coils can be a bit iffy!

 

Other than that, the lack of starting may be a

[WeFixIt]

These kind of starting problems can be very frustrating and some what patience testing!

But the simple things should be checked first before pull everything apart...

If it runs for 5 minutes then dies and herd to restart its not likely to be half of the things listed above!.

Even with the differences between a small engine when cold and hot there are two many reasons

1 fuel

2 electrical

If it runs for 5 mins or more dies and hard to restart sound more likely to be coil or plug to me

If however if it's cutting out after 2 minutes running from cold then fuel is more likely.

 

But that's my opinion and everyone has a different one and a different way of doing things!..

[GardenKit]

Thats a spot on reply WeFixIt, and due to the early hour its probably one not clouded by cider, as most of my late replies can be.

[WeFixIt]

Cider, Beer. Wine

Well it is that time of year! 😉

[Johny Walker]

mine was the same ,took the breather pipe of the bk ,prob soerted been ok since ,bar a new plug