W114 wont idle and backfires

[ggenovez]

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.

[97 SL320]

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

[Sugar Bear]

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!!!