trouble with the running of my W115.

[merc owner]

Hi all, i am having trouble with the running of my 220 w115 mercedes, after being in storage for nearly a year i tried to start it, but the battery was flat, so after charging the battery, the car started but will only run if i keep the gas pedal to the floor and even then the car judders badly, i was wondering if anybody could help me find out whats wrong, many thanks CW.

[joshhol]

Where o where to start. . .

You have more to do than charge the battery. For starters, gas gets old quickly and turns to a varnish. Get fresh gas in it, change the plugs and probably the points, change the oil for sure and try again.

The old gas probably is your biggest problem if the car was running fine when you shut it down. Seals will dry out, so you probably have problems that weren't there before.

Good luck.

[300SDog]

I'd say that's pretty good - the fact it started and ran at all with one year old gasoline that's probably now rated at 57 octane or less.

(edit: or if it's the diesel 220 then replace the fuel filters and add some additive cetane booster to your fuel tank.

[merc owner]

Well the car has some new petrol in (just over a gallon), and it runs a bit better, but it still judders, and the engine will only run if i keep my foot on the gas pedal (not to the floor though), as soon as i take my foot off the gas it stops, any ideas what it could be (had new plugs, points, dizzy cap, rotor arm).

[gmask]

This is a carbureted engine right? Did you sump the old gas out first before adding more gas? Try spraying some carb cleaner into your carbs.. coudl be that the idle jets are clogged. Hopefully you will not need to have the carbs rebuilt to get the sludge out of them.

Try backing the car out into the open air (don't want you to die from carbon monoxide) and run the engine with the gas peddle down for awhile.. if possible have somebody assist you are put a brick on the gas peddle. Observe the engine see if there are any leaks. Check your timing .. try to do a tuneup if possible. Is your muffler rotten? After I rebuilt my engine I had a helluva a time getting it going again until I put a new muffler on.

[300SDog]

Yep, sounds like old fuel varnishing and blocking jets inside carbs. If it was me I'd try to drain em and spray alot of carb cleaner into carb innards, letting it marinate overnight in between treatments.

Have you cracked the carb cases to have a look inside and poured some carb cleaner into the bowls that seeps into passages? It generally evaporates fast if you just spray it on surfaces.

Dunno if tune-up, points, plugs, valve clearance, etc will do any good at all..... assuming the MB was in tune when it was parked.

And another idea is to store these cars bone dry, driving em into reserve (as far as you dare) and then letting them idle until carbs run completely out of fuel - preventive measure against gasoline fouling at long term storage.

[Tomguy]

One theory completely opposes another on how to best store cars.

Some say, better off keeping it full (or nearly full) to prevent rust in the tank and lines. Of course, then comes the issue of probably draining the entire tank, and then filling it with fresh stuff when you go to revive it.

Others say to run it dry, preventing gas from turning into gum in the system as it sits.

Which is the lesser of two evils?

At any rate, 1 gallon of gas will NOT help, You need to fill that tank up! The gas probably left a nice "Jello"-like substance in the lines and in the bottom of the tank, which your fresh gas removed like laquer thinner on gummy varnish. Now you're burning that crap with the fresh gas! I'd pop off a fuel line at the engine, let the pump drain the tank and lines dry into a (gas) container. Then put about half a gallon in, let it sit for 5 mins, then drain that stuff out. Then put fresh 93 in the tank - 10 gallons - with an entire bottle of fuel system cleaner (Fuel injector cleaner, even on a carb engine, will work wonders at cleaning clogged jets).

[300SDog]

Yeah but it sounds like he has no intention of putting the Benz on the road at all - probably just wants to keep it operative.

Here's another idea: Disconnect and plug the fuel line before the fuel pump. Then run a section of feed line from gallon bucket of fresh high octane juice to the fuel pump - skipping the fuel tank completely.

That way you can run the bucket dry if you want and keep the fuel tank filled with old garbage gasoline to prevent rust.

[merc owner]

I am going to run the MB on a regular basis, as i have to drive 380 miles on the monday, drive around london during the week, and then drive the 380 miles back home. Sadly funds are getting low, and i cant fully repair/restore the MB.