Makita saws flooding

[Conner]

I know it has been discussed before but I can’t find the thread. I have two Makita saws an Ea5000 and a EA 7300. The 7300 has just had the bearing journal machined. 
if I leave either saw unused for a week or so they sometimes flood and the plug needs to be removed to get the excess fuel out. Once started they are no bother either hot or cold. The 5000 has done this since new. Any ideas?

[Stubby]

Metering arm set too high ?

[spudulike]

Common reasons for flooding are pulling the saw over too many times with the choke on without it starting or issues with the metering part of the carb that could be metering arm set to high, needle worn, metering spring weak, metering diaphragm deformed and the old favourite - filling the tank right up to the top and leaving the saw in a roasting van in the middle of summer.

[Paul in the woods]

This might be the thread you're thinking of (down the bottom of page 1):

 

[Conner]

I did have the 5000 back to the dealer the first time it happened. Nothing was found and the guy I bought it off ran a lot of Makita saws. I think spud may be right with the heat expanding in the tank as I have more problems in the summer. Just remembered reading something about it in the past will see how it goes. Il check metering arm height. But as it has done this from new don’t think anything is worn.

[bmp01]

You are saying the saws flood by them selves and before you even pull the start cord ?

 

I 'd wager you are at the stage the dealer didn't know what to look for. As above the metering valve and the metering arm must be the culprit, t'is the only control on fuel delivery to the engine. 

Spuds comment about leaving in a hot car  relates to the pressure rise in the fuel tank - what is important here is that the metering valve can be over powered if inlet pressure is high enough, somewhere in the region of 2 bar (30ish Psi) will do it.

If you have the pressure test kit, apply pressure to the carb fuel inlet and look for a leak at low pressures 7 psi and secondly increase pressure to see when the metering valve is lifted off its seat. Treat it with care though if you get to 2 bar / 30 psi that's good enough. 

 

Worth noting: just increasing the spring rate or lowering the metering arm could fix your problem but it might result in poor engine response from low speed. And that might give a clue about how Makita set up their saws. ..

[Conner]

Yea I have pulled the plug after a week on the shelf it’s wet. So looks like fuel leaking when stood. As I say the 5000 has always done this and I have learnt to live with it. It’s sometimes ok the longer I leave it the worse it is. I’ve just got the 7300 and had the rebuild it and this dose the same so wondered if it was a common problem hence my question. Il check the metering arm at the weekend.

[spudulike]

Just fit a new needle and metering spring to sort it. If you had a pressure gauge/pop off gauge, you can test the carb but fitting these new components should sort it. Make sure the metering diaphragm isn't hard or out of shape - replace if necessary. 

The Makita carb is no different than any other saw, just get to know the symptoms and fix.

[Dan Maynard]

Do you store it either brim full, or completely run empty? It says in various manuals to do this, a smaller volume of air in the tank is better to reduce water absorption but we also had a thread once about how topping the chain oil after use reduces leakage. My theory heat whilst running warms and pressurises the tank, topping up releases the pressure and you add cold fuel.

Saying that I don't think any of my saws would actually be flooded if I didn't top them up, that includes a Makita and two Dolmars.

[Stubby]

33 minutes ago, Dan Maynard said:

Do you store it either brim full, or completely run empty? It says in various manuals to do this, a smaller volume of air in the tank is better to reduce water absorption but we also had a thread once about how topping the chain oil after use reduces leakage. My theory heat whilst running warms and pressurises the tank, topping up releases the pressure and you add cold fuel.

Saying that I don't think any of my saws would actually be flooded if I didn't top them up, that includes a Makita and two Dolmars.

A working tank vent should take care of all the above .