poor gas mileage 1200cc

[Damian Gomez]

Okay so I have a 1200cc, stock granny, I did the math three times and my mpg was 14, 17 then 16, and ideas what's wrong? New points, just changed oil, cleaned filter, correct timing, could it be my valves or condensor? The engine runs strong but is a little hard to start

[KTPhil]

What do you know about this engine's history? Done a compression test lately? How old are the spark plugs?
Check for gas leaks, too.

[itskyle]

[Damian Gomez]

never done a compression test, I don't even know how to lol and the plugs, wires and cap are new also. and the fuel sender gaseket is their I just installed it, how would I know if their leaking?

[itskyle]

[my59]

What's the driving style? Fast off the lights, lots of stop and go? It can make a huge difference.
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[drscope]

This may sound silly but one of the first things to check is your tire pressure. If the tires are low you may not see it, but the engine has to work a lot harder to make the car go.

You didn't give us any information on the history of the car or your history with the car so we don;t know if this is a new situation to you or not.

That being said, you may want to get out a tape measure and also check the wheel alignment to make sure it's not way off. If it is the tires will be scrubbing and that also puts a bigger load on the engine.

It could be something simple like this as you don't have a lot of power to begin with, so little things can have a big effect on fuel milage and performance.

You may also want to check your choke adjustment.
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Mother Nature is a Mean Evil Bitch!

[andk5591]

Would also suggest STRONGLY checking your fuel pressue. What carb and distributor are you running.

And whoever said about driving style - jackrabbit starts with a stock 1200? You are kidding, right?

But seriously - how are you measuring you mileage - Best to run at least down to 1/2 tank or a lower - check mileage and repeat at least 3 times and then average. What type of road are you driving and is there a lot of stop and go? If you are running at close to 70 on a freeway, then I can see it being bad since you have it floored the entire time. But not as bad as you are stating.
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D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
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[Aussiebug]

Lots of useful stuff above, so here's a summary.

Easy stuff.
1. Tyre pressures - for stock tyres 18 front and 27 rear will work fine.
2. Brakes binding - or does the car roll easily when in neutral?
3. Leaking fuel - around the tank or from the rubber fuel lines - usually 4 sections of that - under the tank, over the gearbox, and either side of the pump. Anything wet or ends starting to crack needs replacing.
4. Leaking carb - is it wet around the outside? Check fuel level in float bowl - should be about 1/2 inch below the lip (float still in). If it's high, try replacing the needle valve.
5. Fuel pump leaking - check level of oil - if it's rising and smells of fuel, the pump is leaking fuel into the sump.
6. Tight valves - not shutting properly so they leak. If the exhaust valves continue to get tight after normal checks every 3000 miles, they are stretching and need replacing (they usually stretch before breaking!)
7. Choke sticking on. With engine warmed up, take top off carb and the choke butterfly should be upright, or almost so.
8. Timing - most 1200s use 10BTDC, but this might vary depending on the distributor used - non vacuum distributors (the 009) must be set at 30BTDC at 3000+rpm and let the idle fall where it may (usually between 5 and 10BTDC). 30BTDC is 46.5mm to the right of TDC around the pulley rim. Using a 009 usually results in higher fuel use, but not a lot.
9. Driving style. heavy throttle followed by heavy braking uses a lot of fuel. Revving the engine hard in lower gears uses extra fuel. The 1200 engine does not have a lot of power so drivers needs to think SLOW and EASY when driving them.
10. Resting other foot in brake pedal. Sounds silly in a manual gearbox car, but if you tend to do that in the auto Camry (like left-foot braking), the habit can stick.

Harder stuff

1. Compression test - you need a tester - the screw-in style works best. A 1200 engine should give around 120+psi on all cylinders. This pressure drops slowly as the engine ages, once any one cylinder has dropped to under 100psi, it's time to start planning a rebuild - the engine will still usually run OK but with increasing oil burning and poor fuel consumption. If a low cylinder is found, try squirting about 20cc engine loil down the plug hole and retest - if the pressure rises just a little, the rings are probably tast(the oil acts as a temporary seal) but if there is no change, the valve are suspect.

2. Can't think of one.

The 1200 engine should give you close to 30mpg (US gallons). Hal;f that means there is something definitely amiss and you do need to find it.
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Rob and Dave's aircooled VW pages
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[shano63]

What everyone else already wrote and....how are you checking your mileage, from the speedo? Are you sure it reads right? Check it with a gps next time, see if it jives. Doubt its off by that much, but every bit helps.
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Chris

Take it as it comes-- Morrison

[Damian Gomez]

I checked it by finding the miles I drove since I last filled up, then dividing it by how many gallons of gas I put in. and I found out my carb is leaking. their is fuel all around the base gasket where the carb meets the manifold, will this be a simple unbolt and replace the gasket and bolt the carb back on without having to adjust anything? and the second leak is where the fuel hose connects to the carb. someone mentioned to me to lightly tap it with a hammer to push the fitting snug into the carb again.

[andk5591]

If you are leaking as much gas as you are burning, your car have burst into flames by now.

As far as fuel inlet - would suggest pulling the brass tube out - a little JB weld and then tap it back in. AND use a safety wire from your hose clamp to the one of the screws on top of the carb to prevent it from falling back out.

Your carb gasket leaking will do 2 things - it will let gas out, but will also let air in - both are bad things. Fix it. BUT you have been given a bunch of things to check and the first thing you NEED to do it verify your fuel pressure. A buddy just rebuilt a stock fuel pump and the car was not happy because his fuel pressure was real high - will push fuel past the needle valve and dump raw gas into the intake. You need it to be around 3 lbs.
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[Damian Gomez]

okay, just thought of this, when vw rated the average fuel mileage what was it compared to our gas? I use the cheapest, (unleaded I think)

[drscope]

Just for grins and giggles have you pulled the dip stick and checked the oil level lately? If the diaphrame in the fuel pump gets a leak it dumps raw fuel into the oil. You will see the level raise and the oil usually smells of fuel.

And you still didn't give us any information on the history of the car or your history with the car so we don't know if this is a new situation to you or not.

How long have you had the car and how long has it been since you noticed this problem?
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Mother Nature is a Mean Evil Bitch!

[Damian Gomez]

I have checkeed, it does not smell like fuel, I know the car was owned by an older man then he gave it to his teenage granddaughter then sold to the person I bought it from, he said he used it to drive to the mountains for work, I sometimes drive with a heavy foot, but most of the time I think about it and try to have my foot about halfway down so I can tell im accelerating, I drive It in the city so stoplights stop signs, sometimes traffic, and I have had the car almost a year but only started to try to calculate the gas mileage about a month or two ago.

[Helfen]

Most all suggestions are great, but one thing left out is...... did someone put a FWY flyer ring and pinion for this poor 1200 to overcome?

[2nd67]

I don't think a stock vw is capable of 14 mpg without a trail of fuel leaking behind it, or people pulling alongside giving you the #1 based on eye watering exhaust smell. fuel leak, pump diaphragm leak, screwed up carb jetting/choke. figure it out and get back to 25+.

[Damian Gomez]

what does the ring and pinion do??

[andk5591]

What they are talking about is changing the rear end gear ratio. Older VWs have "shorter" gearing because the lower horsepower of the engines needed it to get to and maintain speed. BUT the engine RPMs were higher.

As later bugs got more power and a higher top speed was desired, "taller" gears were used. Its very common to put taller gears in an earlier tranny if the engine has been upgraded. We did this in her 61 bug and the 63 based dune buggy. BUT my 65 (with a 1200) has the stock gearing.

Simplistically, think of it like this - on an earlier bug your fourth gear is bewteen 3rd and 4th of a later bug.

Now - what that would mean to you is is a "taller" gearing was used, you would have your foot in it all the time just getting up to speed and to maintain it. Having things wrong either way will hurt your milage. I kind of doubt that is what you have going on though.
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[andk5591]

Just saw this on another post and can't believe that I didnt think of it - Pop the air cleaner off and start the car. The choke should be closed initially an then slowly open - will take a couple minutes. Should be straight up and down once its warmed up.
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...