FS400 Brush Cutter... Carb or seals.. Vaccum test.

[champagnecharly]

Well i took the cap of the L and the H.. however I couldn't see any screw under the H. in fact it seemed to be just Al

Adjusting the L I managed to get it running. Actually running quite well although a little lean under throttle.. that was well until I moved it and revs dropped. I also noticed that under certain adjustment, when I let go of the throttle revs would drop but take time to drop completely. I thought that whether or not the carb is not 100% the slowness in dropping down in revs and the variation in revs on simply moving the thing must be to do with something else.. I had some oil seals hanging around that came with a gasket kit.. so i thought I would install.. but ohh.. thought it would be easier to pull them out.. how wrong could I be.. Without the stihl tool, how can I get these out? Any tips would be apreciated.

[wisecobandit]

The revs "hanging" and slowly returning to idle is due to it running a lean condition. The reverse if its running rich it would drop quick almost to below tickover and perk back up to tickover speed.

Getting seals out is usually easiest drilling 2 small pilot holes in the seals screwing a self tapping screw in each hole and then a couple of pairs of pliers and a quick yank while holding the engine firmly.

Sounds more to me more like fine tuning is required on the carb tho not seals. On rare occasions some can be pigs to set up.

Why in the initial fitting did you tune it without no air filter?

[champagnecharly]

Thanks..

 

Why in the initial fitting did you tune it without no air filter?

Lazyness. And also thinking it wouldnt make a diff.

[wisecobandit]

Thanks..

 

 

Lazyness. And also thinking it wouldnt make a diff.

 

It will make a big difference and it would be to rich even maybe to start and run once the filter is fitted. Theres a strong chance the engine could well have flooded after the first few pulls especially with choke on which is why it wouldn't start?

[mikerecike]

Did you use any elements of the 'gasket kit' that the oil seals came with?Sounds a little odd?

[champagnecharly]

It will make a big difference and it would be to rich even maybe to start and run once the filter is fitted. Theres a strong chance the engine could well have flooded after the first few pulls especially with choke on which is why it wouldn't start?

 

I don't think so. the problem is the lack of consistency in running also the requirement of constant carb adjustment.

[champagnecharly]

Did you use any elements of the 'gasket kit' that the oil seals came with?Sounds a little odd?

 

I'd ordered the wrong part number when wanting the gasket between carb and body. I used that but also in it was head gasket and oil seals.. nothing odd there..

[spudulike]

I'd ordered the wrong part number when wanting the gasket between carb and body. I used that but also in it was head gasket and oil seals.. nothing odd there..

 

You will not that there are two small holes in the carb gasket, these MUST allign with the small impulse hole in the carb body and the cylinder. If it doesn't, the engine will not start.

 

If the engine won't go, check for compression, spark and make sure the spark plug gets wet after a few pulls on choke.

 

If the carb has been apart, make sure the gaskets are the right way round and correct, make sure the stud in the middle of the diaphragm is the correct length, make sure the choke mechanism is closing fully, make sure the fast idle system for cold start is opening the throttle.

 

Take the spark plug out and turn the engine upside down and pull it over to make sure the engine isn't flooded. Check the coil to flywheel gap is the thickness of the average business card and make sure the flywheel is alligned with the key correctly.

 

That should do it!

[champagnecharly]

Thanks Spud