Dolmar 420 problems

[Luckyeleven]

My faithful 420 is now a non starter, for a while it would start and idle but stall unless given an age to warm up.
No it doesnt start at all, Ive taken the carb apart and cleaned everything, changed the plug, and tank filter. It will cough and run for a second when fuel is supplied directly.
Therefore Im thinking to change the carb, however everywhere that sells the OEM part is either out of stock or eye wateringly expensive, are there any generic models that will fit?
Walbro WTE-6B or ZAMA DM23B. The carb has 3 hose attachements.

[Stere]

Cheapest carb is £38 I have the same saw but it doesn't run when hot

[Stubby]

10 hours ago, Luckyeleven said:

My faithful 420 is now a non starter, for a while it would start and idle but stall unless given an age to warm up.
No it doesnt start at all, Ive taken the carb apart and cleaned everything, changed the plug, and tank filter. It will cough and run for a second when fuel is supplied directly.
Therefore Im thinking to change the carb, however everywhere that sells the OEM part is either out of stock or eye wateringly expensive, are there any generic models that will fit?
Walbro WTE-6B or ZAMA DM23B. The carb has 3 hose attachements.

Have you cleaned out the little round gauze filter on the carb ?

[Luckyeleven]

12 minutes ago, Stubby said:

Have you cleaned out the little round gauze filter on the carb ?

Hi, yep and tried running it without, no difference.

[spudulike]

You may have a split fuel line....if you plug the end the fuel filter goes in and blow down the other end with the line submerged in fuel, you shouldn't get bubbles......I would use a Mityvac to test for leakage but assuming you haven't got one.

The other thing to do is after you have tried to start it on choke etc. remove the carb and see if you have fuel in the pump section (plastic diaphragm cavity) and then check the metering section...the bit with the diaphragm with the round metal disk on it and the metering arm underneath it.

From this, you can tell what the carb isn't doing....pumping fuel up from the tank or passing it through to the metering part. Just make sure the carb is held upright when the cover is taken off so you can see how much fuel is present. The cavities should be full.

Report back with the findings or just work it out for yourself.

I am assuming it is fuel if the saw fires with fuel injected down the carb.

[spudulike]

Worth checking the tank breather as well...not massively likely but possible.

[shavey]

I’ve had two or three that have needed a new carb 

as it’s been said there Zama DM23B part number 161371-1

price at the moment is around £55 2 weeks order 

[Luckyeleven]

After new carb, plug, filters.......and much swearing, it turns out it was the coil. Triggers broom at this point.