Last night I was putting a new alternator belt on, and when I cranked the bolt to tighten the alternator back on, the rear nut twisted which was connected to a bracket of some sort. Anyway, this bracket moved and snapped off a clear plastic tube that looks like it is coming from the carburetor. What exactly is this?

 

was this tube running down to the from passenger side of the engine?

 

No, it leads from the driver side of the carburetor to down to the bottom of the engine compartment.

 

Sound like a line to the oil metering pump.

 

oh, ok so it... wait, what? any chance of a picture, cuz I'm nor sure based on that.
And what ^he said

 

Sounds like an oil injection line

 

Sorry, I can't get a good picture of it. If it is a line to the oil metering pump, where can I get a replacement?

 

There are two lines, a long one and a short one. Mazdatrix carries the short one, the long one is NLA.

If you are lucky then you broke the short one, if not there are several threads here about how to fabricate a replacement.

 

How do I find out which one I broke? They both look the same...

 

yes, those are your oil metering pump feed lines. they are bent slightly differently as one is longer than the other. replace both just to be safe. they are available through the dealer or through mazdatrix.

 

The two white plastic lines going from the driver's side of the carburetor, over the water pump housing, down the front/side of the engine, ends up at the Metering Oil Pump (which some people call the Oil Metering Pump or just the OMP).

This is a little pump that takes oil from the front cover and sends it up those lines into the carb to mix with the gas and lubricate the apex seals.

These lines are VERY IMPORTANT. Very, very important. If your apex seals do not get proper lubrication, you'll break an apex seal and have to rebuild the engine.

The lines are no longer available from Mazda. I recommend you put a Want To Buy thread in the classifieds. In the meantime, you can protect your engine by mixing some two-stroke oil into your tank. Yes, that's the same two-stroke oil that goes in your snowmobile, dirtbike or boat. Put 100mL per Litre (others on here can tell you what that is in imperial, I think they say an ounce per gallon? I'm not sure).

As long as you're running two-stroke, you don't need those lines. But it's a pain in the *** to do that every fill up (though some people do it) so you should get those lines fixed.

Jon

 

IMHO pre-mix is pretty damn easy. I havent had a working MOP for years now, all my engines get fed a good ~100:1 premix ratio...its already second nature to measure/dump oil in my tank prior to filling up on fuel

 

use 1/8 inch id rubber hose?

No this isn't the purist OEM Pebble Beach Concours d'Elegance solution, but the apex seals will get the lubrication

good time to check the oil metering pump flow rate.

 

With a broken line, even if you pre-mix you're gonna get oil all over the place. Either the line needs to be fixed or the OMP needs to be removed and replaced with a blocking plate.

If the line just broke in one place, find some rubber tubing that tightly fits over the tube diameter. Cut a piece of it a couple or three inches long, push both the broken ends or the plastic tube into the rubber tube, and then seal the edges with an oil-proof silicone.

You could maybe even get by with using heat-shrink tubing, but I'm not sure how durable that would be over time. It's not really made for oil-proof use.

 

I'm looking at getting this: 79-85 12A Rx7 Oil Metering Line Kit (ARE99)...

Does anyone know if this company is reliable? Also, how do I go about replacing the lines once I get them? It seems to me like the oil metering pump is hidden.

 

I've yet to buy from atkins but, they get good reviews on here. If you need a temp fix do what DD said it works great.

 

Atkins has been around for a long time. It'd be hard to mess up something as simple as tubing.

 

+1 for Atkins. Dan has helped me out of some tough spots over the years. They're good people and have been around for ages. Go for it.

Jon

 

How do I check this?

 

chilton's/clymer's manual has the procedure......basically you run the engine at 2000 rpm for 5 minutes and check for 2 cc's of oil from the oil lines that go to the carb.

I use a paper towel, if there is about a 1/4 inch spot on the paper towel, then that's about 2 cc's. Before everyone slams me, I will have you know that my rotary has 220k (before the rebuild) and then 25k on the rebuild.

Or you can shorten the adjustment rod until you get carbon on the plugs, then you will know that you are at the upper limit of oil metering flow rate.

 

Sorry, man, but you just sent my engineer brain into overdrive.

Geometry:
2CC = 2 cubic centimeters, a volume 1x1x2 centimeters in measurement.
Converted to cubic inches, that's 0.122 CI's
Area of a 1/4" circle = 0.05 sq inches.

In order to have 2cc of volume contained in a 1/4" diameter 'puddle,' the puddle would have to be 2.48 inches deep.

That's a pretty amazing paper towel.

I'm thinking that your paper-towel test is using a different value for either time, or RPM.

If you're only getting a 1/4" puddle on a paper towel out of your OMP over 5 mins at 2000 RPM, it's running way below spec.

Not slamming you - just keeping it real.

 

Go to home depot or lowes and pick up chainsaw/trimmer gas line. Its about the right diameter,
will slide over the existing broken tubing and is gas/oil proof. I've been using it for a few years
when I replaced the rubber lines going from the lines to the carb barbs.

Did I mention its cheap and you can get it TODAY!

 

Divi, so how would you measure it?

 

The way I do it is to use epoxy mixing cups, they are graduated in cc's and are easy to come by. Disconnect the omp lines at the carburetor, run the engine at 2000 rpms for 6 minutes and collect the discharge in the cups. Should be 2-2.4 ccs. Be aware that the engine will need lubrication during this period. I just watch the dropes comming out of the tubes and drip the approximate same amount into the primary throats of the carburator.