What's up with my blower

[daveindales]

Ok, I've got a bg85 blower. Had it years now. It will only run properly with the petrol cap unscrewed. I've changed the tank vent, checked the fuel lines to the carb. These are all clear. Replaced the fuel filter, and replaced the carb, and it's still got the problem. Any one any suggestions?

[Stubby]

Ok, I've got a bg85 blower. Had it years now. It will only run properly with the petrol cap unscrewed. I've changed the tank vent, checked the fuel lines to the carb. These are all clear. Replaced the fuel filter, and replaced the carb, and it's still got the problem. Any one any suggestions?

 

Replace the fuel cap or clean/clear the vent in it .

[daveindales]

I took a look at the fuel cap but could not find a vent in it. Is there one in a bg85?

[Stubby]

I took a look at the fuel cap but could not find a vent in it. Is there one in a bg85?

 

Maybe , maybe not but it seems to be the only link since you have changed / checked everything else . Worth a try for the price of a cap . Maybe try one of another that you know works ?

[Sawchip]

Ok, I've got a bg85 blower. Had it years now. It will only run properly with the petrol cap unscrewed. I've changed the tank vent, checked the fuel lines to the carb. These are all clear. Replaced the fuel filter, and replaced the carb, and it's still got the problem. Any one any suggestions?

Odd one this as with all the parts you have fitted things would have been taken off so disturbing bad gaskets/lines and so on. New carb ? not carb kit ?

Is it a build up to poor running with the cap on of fairly instant.

Would take a bit to vacuum lock the tank..less if its full .

[daveindales]

There is no vent in the cap. I've put a new carb on with new gaskets. Put a new fuel filter and new tank vent on. I've checked the fuel likes and they are clean, with no leaks.

 

The blower will rev up from cold, then the revs just slowly die off. If I open the fuel cap, then the thing runs ok. I'm wondering if the new fuel vent is faulty. Am I missing something else.

[Sawchip]

There is no vent in the cap. I've put a new carb on with new gaskets. Put a new fuel filter and new tank vent on. I've checked the fuel likes and they are clean, with no leaks.

 

The blower will rev up from cold, then the revs just slowly die off. If I open the fuel cap, then the thing runs ok. I'm wondering if the new fuel vent is faulty. Am I missing something else.

 

As long as there isn't anything up with the parts you have fitted then it seems to still point to a fuel starvation issue. The vent will allow you to get some air through it if you take it out and suck on the inside tank side …OR..take it out all together if pos and run the blower up with the fuel cap on. At least that should show some result as to the vents worth.

All points to fuel starvation though from what you say.

[daveindales]

One thing I have noticed, is when I remove the fuel cap and Rev the blower, there are lots of bubbles coming through the fuel inside the tank, and it splashes out of the open top. Not sure if this is normal.

[Sawchip]

One thing I have noticed, is when I remove the fuel cap and Rev the blower, there are lots of bubbles coming through the fuel inside the tank, and it splashes out of the open top. Not sure if this is normal.

Things churn about inside a tank on a saw ,blower,brush cutter ,ect a fair bit as normal. Don't think thats out of the ordinary from your description ,but with regard to "bubbles" Not sure on that one. Difficult to comment on that exact point without eye on observation.

[spudulike]

By request.......I have one of these blowers, one thing to check is that the manifold has been put on back to front as it has a hole for the impulse and you can easily put it on the wrong way round - make sure the hole in the inlet manifold lines up with the hole on the cylinder and the carb.

 

Mine had this issue and is probably the one to go for!

 

Other than that - the bubbling suggests the needle valve may be leaking so worth pressure testing the carb and also check the fuel line is not split.

 

If all the above fails - make sure all the gaskets on the carb are in the correct place - it is easy to get the pumping diaphragm one in the wrong place!