Marquette Combustion Analyzer

Has anyone here ever seen one of these? It was a strange impulse buy for me today and I was hoping it would be something I could use in the shop but can't find information on it anywhere online. Tag on the back says model 42-108

 

Does it work? You got the probe with it. The top gauge is the exhaust gas analysis, connecting to the probe. The bottom appears to be only a vacuum/pressure gauge, connected to the nipple on the front. I'd guess that's what the fittings are for. What's inside the case? It may need some new capacitors if it has a power supply inside.

I would look online for instruments that claim the same function, like this Heathkit:



Possible you can find instructions or other documents that will help to understand what you've got.

 

Search for Marquette Instruments. I found two other Marquette analyzers on eBay - Vintage MARQUETTE Model 41 211 Combustion Analyzer | eBay

 

Looking at it, assuming the meter is powered up with fresh batteries or whatever:
With the probe in free air, you have two adjustments. "Adjust" first to the green arrow (zero). Switch to "Balance" and adjust to the red arrow (O2 in air). Put the probe in the exhaust pipe and look at the meter. Of course, this will not work if the car has a catalytic convertor.

 

It uses D cell batteries for a power supply. I haven't been able to find any user manuals for this model online anywhere. It might be a week before I get a chance to try it out but hopefully it works.

 

Not sure you need a manual. For the O2 meter, if it works, you read the gauge. The vacuum gauge is like any other vacuum gauge.

 

Have you looked inside? Stuff like this can be ruined when someone leaves the batteries in them and they leak.

 

I have one, or I think I still do. I was never able to get any really satisfactory results out of it. Now, welding a bung in the exhaust below the manifolds and installing a wide-band O2 sensor, that works great!
Oh, it's still on the shelf. Wants 3 "D" batteries. Just turn it on and let it warm up for a good 3-5 minutes before switching to adjust, then use the adjust knob to set the needle to the balance line.
The basic technology isn't awful, run the gas between a light source and photodetector and use a narrow-band filter to just detect the oxygen absorption line.
I think the challenges with this very first-order system are the lack of a pump, so you rely on the exhaust pushing gas through the system, and the lack of a particle or moisture filter which allows too much dirt and water droplet residue to mess up the results. Use a big aquarium pump and a in-line fuel filter and your results would improve greatly.