Tuning up a 1275

[jehuie]

My Morris Minor has a 1275 in it. It's runs pretty good but smells fairly strongly of gasoline when it's running. I'm a relative novice and thought I'd just ask here about where to start.

I'm thinking the obvious is to check the spark plugs and then to find online directions for tuning up the carbs. Is it likely that something is broken with the carbs though? Like maybe the float not working causing fuel to overflow? I don't see evidence of leaking but that smell....

 

[Boink]

As you state, sometimes such fuel smell is due to carb float-bowl overflow (due to the floats, level adjustment or needle-valves).

 

[DrEntropy]

Check at the undersides of the carbs for wet gas. If there's no evident dripping, I'd start looking at the fuel lines. Any of the connections where steel lines meet rubber/flex lines. Clamps etc. for weeping. Also the top fo the fuel tank for rust-through, pinholes or connections there.

 

[NutmegCT]

Figuring you haven't owned the MM for long, first thing I'd check would be drips of gas below the carbs and bowls.
Tom M.

 

[jehuie]

Ha ha. You would think so but I've had this sucker for over 20 years! But I don't put many miles on it and haven't driven much over the last couple years. I used to have a couple friends (and a father) who would help me out with it as needed but most of them (including my father) have since passed on or are otherwise not available. In any case, I've never been great mechanically. I don't have a garage or a lot of tools. But I do enjoy tinkering on it and just retired so I finally have time to do so.

But I haven't messed with the carbs in easily over 10 years....

 

[drooartz]

Is the fuel smell coming from the engine bay, or something you're smelling when you're driving? I ask because I had a fuel smell in my Minor and it went away when I replaced the fuel sender gasket and filler hose at the gas tank. They were perished enough to let vapors into the cabin.

 

[jehuie]

Is the fuel smell coming from the engine bay, or something you're smelling when you're driving? I ask because I had a fuel smell in my Minor and it went away when I replaced the fuel sender gasket and filler hose at the gas tank. They were perished enough to let vapors into the cabin.

People around the car could smell it mostly. I checked all the locations that people mentioned and could find no evidence of fuel leaking at all. But then, I'm also not smelling it the last couple times I ran it either which is strange. The only thing that I changed is that I removed the air filters while I'm waiting for some new ones to be delivered. I did notice that the old air filters smell strongly of gasoline though. Which does not seem like it should be the case...

 

[jehuie]

And on a related note…all my plugs look good except for this one. It’s the second from the front of the engine and has strong carbon build-up covering everything including the white porcelain.

What is this spark plug telling me is wrong? Not getting good combustion to burn it off I imagine. But what would need to be done to figure out why?

 

[Boink]

Have valves been recently adjusted? How's compression in all cylinders?

 

[jehuie]

Have valves been recently adjusted? How's compression in all cylinders?

Is 15+ years ago recently? I haven't checked compression yet. I don't have the tools to do so yet.

 

[Boink]

With one fouled plug, short of a poor electrical connection to it, I'd suspect a valve first.

 

[jehuie]

With one fouled plug, short of a poor electrical connection to it, I'd suspect a valve first.

I just watched a video on how to do the valve adjustment and it looks really straight forward. I'll give that a shot.

Here's the video I found:

 

[Boink]

Yep... that's basically it.

 

[jehuie]

Well that made a nice difference. And not nearly as difficult or complicated as I always thought it would be.

Maybe I won’t wait 15 years to adjust them again next time!

 

[NutmegCT]

Next step - clean that dirty plug, then drive for a couple hours. Check the plug again and see if it's still getting the carbon buildup.

 

[jehuie]

Next step - clean that dirty plug, then drive for a couple hours. Check the plug again and see if it's still getting the carbon buildup.

I replaced all the plugs earlier. But I can certainly pull that one later and take a look. Thanks!

 

[Boink]

If still a problem, then you may have a sticky valve.

 

[Pat MM]

On my sprite that gets started once or twice a year for over 15 years I had a fuel smell at one time, also intermittent. It was a flex rubber fuel line that was weeping, but not dripping. Simple fix, but took a while to find...