Stihl BR800x loses power and bogs after 30-45 minutes of operation

[eltut]

I haven't been able to figure this one out. Runs fine until 30 - 45 minutes in when it starts losing power, gets boggy, and won't rev up to WOT. I have cleaned and then just removed the spark arrestor, new air filter, new fuel filter in the tank, new spark plug, and fine tuned the carb. Any ideas?

 

[slomo]

Get an inline spark tester. See if she loses juice after 30 mins. Make sure the ignition coil has a good ground. Parts heat up and lose connections......

 

[eltut]

Thanks slomo. Someone else mentioned the ignition coil as well and also checking the gap, (which I will have to look up) does that sound correct? I have not cleaned it as you described but I will make sure I do that!

 

[ILENGINE]

Get an inline spark tester. See if she loses juice after 30 mins. Make sure the ignition coil has a good ground. Parts heat up and lose connections......

But also need to keep in mind that the new spark advance with built in rev limiter ignition modules may not loose spark and still be faulty.

 

[Tiger Small Engine]

I haven't been able to figure this one out. Runs fine until 30 - 45 minutes in when it starts losing power, gets boggy, and won't rev up to WOT. I have cleaned and then just removed the spark arrestor, new air filter, new fuel filter in the tank, new spark plug, and fine tuned the carb. Any ideas?

Check the fuel tank breather. These can get clogged up and cause fuel starvation.