Your Little Pump That Can’t Suck

In farm country things tend to get used forever as long as they still “kinda” work. Oh, people will trade tractors and combines off just to drive something new much like city folk do with cars. When it comes to things like chemical pumps and hay elevators as long as you can nurse them along you nurse them. Well, that is until the oldest child who gets stuck nursing it along decides enough is enough.

During planting season this year enough became enough. We have had this Red Lion Model 5RLGF8 Type A agrichemical pump for a lot of years. Memory fails me as to when we got this thing. Possibly when I was in High School. Yes, the Briggs & Stratton 900 Series motor on it is a classic Briggs, incredibly noisy, but it still starts with the first pull and surprisingly the muffler hasn’t yet rotted off.

Those of you who did not grow up on a family farm during the 60s and 70s will be unaware just how much “junk in a box” chemical pumps used to be. If you got two crop seasons out of them you were lucky. The mufflers seemed to rot off the first season and it was a betting game to see if the pump housing would wear through before the piston disconnected itself from the crank shaft (always an exciting and inconvenient moment!) Somewhere along the way Red Lion figured out how to make a good one.

Given most of you grew up in the city I need to explain a bit about what goes through these pumps. Early in the season you have liquid fertilizer with either 32 or 28% nitrogen content. Sometimes this is called “starter” fertilizer. It has a rather strong ammonia smell to it and if spilled/splashed on a pair of work boots can ruin them before the season is over. Sounds nasty doesn’t it? Well, be that as it may, it is still safer than anhydrous ammonia.

Next you have your post emergence weed spraying. While this is put on with either 10 or 20 gallon per acre of water it is a mix of other nasty chemicals and some crystal/power like products blended in a mixing tank and pulled through the pump before the solids are completely dissolved. (Agitation in the sprayer tank completes the blending.) You will also have a round of side dressing, knifing into the ground between the planted rows of corn which is another pass of liquid fertilizer.

Not to bore you too much with numbers, but on a 3000 acre farm the post emergence spraying at a 20 gallon rate is 60,000 gallons required for spraying. These types of pumps are on the nurse or trailer tanks used to transfer from source to the implement in the field so they get to pump it twice. Once into the trailer tank and again into the implement. In short, these pumps are at the front of the line when it comes to abuse.

So, assuming your pump engine is fine, your first indication that these self priming pumps are a fighter on the ropes is when they start having trouble self priming. You won’t notice this during regular transfers. Be it water or liquid fertilizer your source tank will have thousands of gallons in it pushing through the pump before you start the engine. Likewise, your trailer tank will have roughly a thousand gallons in it pushing through the pump before you begin transfer to the implement. You won’t notice this until you are at the clean out stage. When cleaning a sprayer or fertilizer implement you will only have about 100 gallon of water in the trailer. Then you get to play the game of holding the 2″ suction hose above the pump and pouring water into the pump so it starts full to get primed.

Why does your self priming pump lose its prime?

0530161306 The impeller at the top is the one which came out of the pump. The one at the bottom is the new one I installed. Yes, the old one started out looking just like this one. It didn’t wear just at the face, but wore at the edge as well, shrinking it in diameter.


Above is a close up of some of the discoloration from the first picture. Nasty kind of hurt isn’t it? You might be surprised to learn that, having done this kind of work all of my life, it wasn’t until I hit this “north of 50” age bracket I had never replaced an impeller in a pump. Until we got this pump none of them lasted long enough.

Didn’t you just put a new engine on your pumps when the piston disconnected from the shaft? No. The dirty little secret with transfer pumps is they tend to have custom shafts on the motors. Try as you might you can never seem to find a replacement engine with the same length, taper and key way size as the one which just wiped out. Pump manufacturers tend to get custom runs from engine manufacturers.

Didn’t you try rebuilding one of those engines? No. When the piston disconnects from the crank shaft in a small engine it does all kinds of internal damage, especially to the crank shaft. Since it was a custom crank shaft, you could never get a replacement.

In high school I took a small engine repair class. Before I found computers I actually thought of making a career out of that. Each winter the local farm supply company would bring in all of their transfer pumps for the class to work on. They brought the dead ones in to be organ donors for the fixable ones. We would swap carbs out, replace seals and if an engine was simply ceased we would knock the piston out hone and ring, but, we were always told if it was disconnected from the shaft not to bother. After we opened one such engine we found out why. Aluminum blocks do not tolerate stuff flying around free inside of them at high speed. Those we would strip down separating out the parts, especially the blocks. When there was a big enough pile for the back of a pickup truck the supply place would turn them in to a recycling center.

Did I mention that they had a lot of transfer pumps? The class was a win-win. They got all of those things tuned up and we got a bit of education. The quality of the pump ends was so bad back then none of us ever replaced an impeller. Last week I finally did. I wonder if my old high school still has that class? If they do I bet that class is replacing impellers. Pumps have finally gotten good enough.

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