STIHL BR800C

[Dustalex1]

Hi all, I’ve been a complete idiot and put Aspen 4 in my (newly bought used but relatively new) BR800C blower. It ran fine for 45 mins. Then a week later I realised how stupid I’d been and that it’s 4-MIX and 2 STROKE! drained tank, replaced with Aspen 2. It ran for 10 mins then died. Now I can’t restart. The irony of all this being that I used aspen to hopefully look after the engine. Have I completely ruined the engine or is there any way back for me to fix my mistake? Thank you so much in advance for any help.

[openspaceman]

52 minutes ago, Dustalex1 said:

Hi all, I’ve been a complete idiot and put Aspen 4 in my (newly bought used but relatively new) BR800C blower. It ran fine for 45 mins. Then a week later I realised how stupid I’d been and that it’s 4-MIX and 2 STROKE! drained tank, replaced with Aspen 2. It ran for 10 mins then died. Now I can’t restart. The irony of all this being that I used aspen to hopefully look after the engine. Have I completely ruined the engine or is there any way back for me to fix my mistake? Thank you so much in advance for any help.

With a bit of luck the bottom end and small end bearings will be fine but I expect the piston will have transferred a bit of aluminium to the bore and the rings will be seized in their lands. Whip the exhaust off and look, maybe post a picture of the rings through the exhaust port.

 

The bore will probably be okay as it is hard but will need the aluminium chemically cleaned off and then "honed" with some wet and dry paper. Probably worth getting an OEM piston if it is that young.

[GarethM]

Could just need a carb rebuild.

 

If you turn it over does it feel okay, splash of fuel on the air filter should get it firing for a minute or two just to see if it sounds okay or a bag of spanners.

[spudulike]

Unfortunately, you won't be able to see the piston through the exhaust port as it is a four-stroke...sorry Openspace......

Also, if it is anything like the BR600 and most other Stihl 4T machines, they have built in decomp systems so the engine will feel pretty lacking of compression on the handle and in my experience, they only feel high on compression when the valve tappets need adjusting as the decomp system lifts the valves slightly on starting so the engine is easy to turn over and excessive tappet clearance messes this up.

You could open up the tappet clearances and see if the compression feels strong or If you have two machines, a compression gauge could be used to measure the compression on both.

Stihl 4T machines are sort of four stroke machines but they use 2 stroke mix to lubricate the moving parts usually lubricated by a wet sump (as in your car) or forced fed lubrication systems with oil coolers like you may find on some race engines.

Running the machine on Aspen 4 may have damaged the main bearings, big end, small end, piston and any other bearing, bearing surface etc. It is almost impossible to say what has happened to this machine but the only positive is that the machine ran OK on Aspen 2 for 10 mins before failing so perhaps it isn't too serious so....all you need to do is check the machine has spark, fuel and compression. If it has and the spark is happening at the right time (ignition timing correct) it should run. 

[pleasant]

Spud is correct. Piston isnt visible....not by removing the exhaust or even the carb.

 

I do have a list somewhere which i made up for new machines we sell of their compression psi. Particularly the 4 mix and the little honda gx25 and 35's etc which have a similar valve arrangement and just as impossible to view the piston. I will did it out and come back to you, although i do have a feeling in the stihl wsm they do give an idea of what is the factory psi, so may be worth a google. I know honda do, and something is telling me they did the same with one of their 4 mix engines of the stihl. If you know someone with a borescope then remove the plug and have a look inside..still wont be able to view the side of the piston by you will be able to see any scoring or surface transfer to the barrel

Edited January 6 by pleasant

[manco]

8 hours ago, Dustalex1 said:

Hi all, I’ve been a complete idiot and put Aspen 4 in my (newly bought used but relatively new) BR800C blower. It ran fine for 45 mins. Then a week later I realised how stupid I’d been and that it’s 4-MIX and 2 STROKE! drained tank, replaced with Aspen 2. It ran for 10 mins then died. Now I can’t restart. The irony of all this being that I used aspen to hopefully look after the engine. Have I completely ruined the engine or is there any way back for me to fix my mistake? Thank you so much in advance for any help.

well i cant help but youre officially a dick.

[Joe Newton]

23 minutes ago, manco said:

well i cant help but youre officially a dick.

Why? He made a mistake.

 

You sound like an angry little man.

[pleasant]

Here you go: Compression pressure should be between 7.5 and 8.5 bar.

 

Here's the page from the WSM:

 

 

[Stihl123]

How old is it? 

 

My br800 wouldn't restart once warm, did some research and people said its the side start recoil 

So got a standard br800 recoil, not side start and that's sorted the issue!! 

 

When u said wouldn't restart that's why my thinking was 

 

I have the stihl part number if u need 

[manco]

15 hours ago, Joe Newton said:

Why? He made a mistake.

 

You sound like an angry little man.

no not angry, a bit harsh maybe. 

not sure why anyone would think any blower or hand tools wasnt 2 stroke.

plus i did say it wasnt helpful