W114 wont idle and backfires
 

Hi all.

Have a w114 250.

Been sitting for a few years but cleaned out the tank and carbs.

Set the timing and dwell. Firing order is correct

Cranks but wont start unless I put my hands over both barrels on both carbs.

Once it does start she'll sputter and die and backfire through the carbs.

Any ideas would be greatly appreciated.

Pull the carburetors apart and clean them, you have a lean condition.

Agree, sounds like dirty carburetors causing a lean condition. If you aren't experienced with carburetors those are difficult carbs to start learning on. Don't try to run it a lot until the carbs are cleaned to prevent burning a valve.

Those engines are also sensitive to having good fresh spark plugs. A fresh set at the the time of carb cleanup is suggested.

Good luck!!!